WO2011021345A1 - Image processing device and camera system - Google Patents

Image processing device and camera system Download PDF

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Publication number
WO2011021345A1
WO2011021345A1 PCT/JP2010/004559 JP2010004559W WO2011021345A1 WO 2011021345 A1 WO2011021345 A1 WO 2011021345A1 JP 2010004559 W JP2010004559 W JP 2010004559W WO 2011021345 A1 WO2011021345 A1 WO 2011021345A1
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compression
image
processing circuit
determination
scene
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PCT/JP2010/004559
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French (fr)
Japanese (ja)
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方城正博
北村臣二
小川雅裕
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パナソニック株式会社
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Publication of WO2011021345A1 publication Critical patent/WO2011021345A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/41—Bandwidth or redundancy reduction
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N23/00—Cameras or camera modules comprising electronic image sensors; Control thereof
    • H04N23/60—Control of cameras or camera modules
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/102—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or selection affected or controlled by the adaptive coding
    • H04N19/124—Quantisation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/136—Incoming video signal characteristics or properties
    • H04N19/137—Motion inside a coding unit, e.g. average field, frame or block difference
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/136—Incoming video signal characteristics or properties
    • H04N19/14—Coding unit complexity, e.g. amount of activity or edge presence estimation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/142—Detection of scene cut or scene change
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/134—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the element, parameter or criterion affecting or controlling the adaptive coding
    • H04N19/146—Data rate or code amount at the encoder output
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/169—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding
    • H04N19/17—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object
    • H04N19/172—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the coding unit, i.e. the structural portion or semantic portion of the video signal being the object or the subject of the adaptive coding the unit being an image region, e.g. an object the region being a picture, frame or field
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N19/00—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals
    • H04N19/60—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding
    • H04N19/61—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using transform coding in combination with predictive coding

Definitions

  • the present invention relates to an image processing apparatus and a camera system including the image processing apparatus, and more particularly to a camera system having a function of correcting a quantization parameter at the time of image compression.
  • Digital video cameras that mainly capture moving images and digital still cameras that primarily capture still images are widely used. Some of these are capable of capturing both moving images and still images.
  • so-called camera-equipped mobile phone terminals equipped with a digital camera function, camera-equipped portable electronic notebooks, and the like have been widely used.
  • moving image data and still image data obtained by imaging are recorded on a recording medium (storage medium) with a large amount of data and a limited recording capacity. If it is recorded as it is, the recording capacity of the recording medium will be full immediately. For this reason, when imaging and recording image data on a storage medium, data compression processing is performed by various methods to reduce the amount of data and then recording on the storage medium. For example, when the image data to be recorded is moving image data, a data compression method such as the MPEG (Moving Picture Experts Group) method is used. When the image data to be recorded is still image data, JPEG ( Data compression methods such as the Joint Photographic Experts Group method are used.
  • MPEG Motion Picture Experts Group
  • a conventional image compression apparatus compresses an image to a predetermined data size in a stepwise manner in a conventional apparatus that compresses still image data using, for example, the JPEG method (see, for example, Patent Document 1).
  • the compression process is performed a plurality of times (since the retry of the compression process is repeated), the time required for the compression process becomes long. For this reason, in the case of a camera system using a conventional image compression apparatus, since it takes time to compress image data to be captured and recorded, there is a problem that the imaging interval cannot be set short. Further, when the compression process is repeated several times, a large-capacity memory that holds all data of the original image is required. On the other hand, in order to keep the compression rate to a predetermined data size by a single compression process, it is necessary to set the compression rate higher. If the compression rate is increased more than necessary, the data size falls within the predetermined size.
  • an object of the present invention is to provide an image processing apparatus and a camera system that can avoid the occurrence of code amount over even in a scene where code amount over has occurred conventionally.
  • an image processing apparatus acquires an image from an image sensor and generates luminance data and color difference data of the acquired image, and the image processing circuit generates the image processing circuit.
  • a compression processing circuit that obtains the luminance data and color difference data as an input image, sets a compression rate, and performs encoding including quantization on the input image according to the set compression rate, and the compression processing circuit
  • At least one of the compression processing information that is information related to the encoding and the image information that is information related to the encoded image generated by the previous encoding in the above is acquired from the compression processing circuit, and the acquired compression processing Whether at least one of the information and the image information is a compression state determination that is a determination regarding the compression state in the encoding, whether a scene change has occurred in the input image
  • the quantization parameter is set to an appropriate value in advance, and the problem that the code amount increases can be prevented.
  • the quantization parameter is a parameter corresponding to the quantization step, and takes a larger value as the quantization step is larger.
  • the image processing apparatus uses the compression processing information acquired from the compression processing circuit as a compression rate relative to the first invention, and compares the acquired compression rate with a predetermined threshold value. By doing so, the compressed state determination is performed.
  • the image processing apparatus provides the code obtained by using the compression processing information acquired from the compression processing circuit as a code amount in encoding by the compression processing circuit, as compared to the first invention.
  • the compression state determination is performed by comparing the amount with a predetermined threshold value.
  • the image processing apparatus provides the bit rate of the code generated by the encoding in the compression processing circuit as the compression processing information acquired from the compression processing circuit in the first invention.
  • the image processing apparatus is characterized in that the compression state determination is performed by comparing the acquired bit rate with a predetermined threshold value.
  • the image processing apparatus acquires the complexity of the image as the image information acquired from the compression processing circuit, and previously sets the complexity of the acquired image to the first to fourth aspects of the invention.
  • the image processing apparatus is characterized in that the scene complexity determination is performed by comparing with a predetermined threshold value.
  • the image processing apparatus obtains the amount of motion of the image as the image information obtained from the compression processing circuit in the first to fourth aspects of the invention, and sets the amount of motion of the obtained image in advance.
  • the image processing apparatus is characterized in that the scene change determination is performed by comparing with a predetermined threshold value.
  • the image processing apparatus is an image processing apparatus characterized in that the quantization parameter of the next frame is set in units of frames as compared with the first aspect of the invention.
  • the image processing apparatus is an image processing apparatus characterized in that the quantization parameter of the next GOP is set in GOP (Group of Picture) units as compared with the first aspect of the invention.
  • the image processing apparatus in contrast to the first, seventh or eighth aspect, adds a constant value to the quantization parameter when there is a scene determination and the low compression state continues.
  • the image processing apparatus in contrast to the first, seventh, or eighth aspect, performs a quantum subtraction by subtracting a constant value from the quantization parameter when there is no scene determination or when a high compression state continues.
  • the image processing apparatus has a scene determination and counts a low compression state with respect to the first, seventh or eighth invention, and the count value exceeds a certain threshold value.
  • the image processing apparatus counts no scene determination or a high compression state with respect to the first, seventh or eighth invention, and the count value exceeds a predetermined threshold value.
  • the camera system according to the thirteenth aspect of the invention is a solid-state imaging device that converts light received through a lens into an electrical signal and outputs it as an imaging signal;
  • a camera system including a digital conversion circuit and the image processing apparatus that performs image processing by inputting an image from the analog / digital conversion circuit.
  • the quantization parameter is set to an appropriate value in advance, and the problem that the code amount increases can be prevented.
  • An image processing apparatus and a camera system using the image processing apparatus at the time of next compression using at least one of a compression rate, a code amount, a bit rate, an image complexity, and an image motion amount acquired from the compression processing circuit.
  • FIG. 1 is an overall configuration diagram of a camera system according to the present invention.
  • FIG. 2 is a flowchart for acquiring the complexity of the image and determining the scene complexity.
  • FIG. 3 is a flowchart for acquiring a motion amount of an image and determining a scene change.
  • FIG. 4 is a flowchart for acquiring the compression rate and determining the compression state.
  • FIG. 5 is a flowchart for acquiring the code amount and determining the compression state.
  • FIG. 6 is a flowchart for acquiring the bit rate and determining the compression state.
  • FIG. 7 is a flowchart for setting the quantization parameter.
  • FIG. 8 is another flowchart for setting the quantization parameter.
  • 9A and 9B are external views of the camera system according to the present invention.
  • the present invention relates to a camera system using a compression processing circuit, in particular, using at least one of the compression rate, code amount, bit rate, image complexity, and image motion amount of the compression processing circuit, A method for calculating the optimum quantization parameter will be described.
  • FIG. 1 is a block diagram of the camera system of the present invention.
  • a camera system 109 includes a sensor (solid-state imaging device) 101 for inputting an image, an AFE (Analog Front End) 102 for converting an analog signal into a digital signal, an image processing device 110, an LCD 108, and a memory 104.
  • a sensor solid-state imaging device
  • AFE Analog Front End
  • the sensor 101 is a solid-state imaging device such as a CCD or CMOS sensor that converts light received through a lens into an electrical signal and outputs the signal as an analog imaging signal.
  • a solid-state imaging device such as a CCD or CMOS sensor that converts light received through a lens into an electrical signal and outputs the signal as an analog imaging signal.
  • the AFE 102 is an A / D converter that converts an analog signal output from the sensor 101 into a digital signal.
  • the memory 104 is a memory for holding images before and after compression, and is, for example, a detachable nonvolatile memory.
  • An LCD (Liquid Crystal Display) 108 is a liquid crystal display that displays a menu for interacting with an operator of the camera system 109 and a captured image.
  • the image processing apparatus 110 compresses the image obtained by the sensor 101 and stores the compressed image in the memory 104, reads the image from the memory 104 and displays the image on the LCD 108, or interacts with the operator via the LCD 108. LSI or the like.
  • the image processing apparatus 110 includes an image processing circuit 103, a compression processing circuit 105, a control processing circuit 106, and an LCD I / F (interface) 107.
  • the image processing circuit 103 is a circuit that acquires an image obtained by the sensor 101 via the AFE 102, generates luminance data and color difference data from the acquired image, and stores them in the memory 104.
  • the compression processing circuit 105 acquires luminance data and color difference data generated by the image processing circuit and stored in the memory 104 as an input image, sets a compression rate, and performs the acquired input image according to the set compression rate.
  • This is a circuit that performs encoding (compression processing) including DCT conversion and quantization according to the MPEG standard.
  • the control processing circuit 106 is compression processing information (compression rate, code amount, bit rate, etc.) that is information related to the encoding in the previous encoding in the compression processing circuit 105, and an image that is information related to the encoded image. At least one of information (complexity of image, amount of motion, etc.) is acquired from the compression processing circuit 105, and at least one of the acquired compression processing information and image information is related to a compression state in encoding by the compression processing circuit 105. The determination is performed by at least one of a compression state determination that is a determination, a scene change determination that is a determination regarding whether or not a scene change has occurred in the input image, and a scene complexity determination that is a determination regarding the complexity of the input image.
  • the compression processing circuit 105 sets a quantization parameter for the next encoding.
  • the control processing circuit 106 has a function of performing all of the compression state determination, the scene change determination, and the scene complexity determination.
  • a scene change determination unit that performs a scene change determination.
  • a scene complexity determination unit 114 that performs scene complexity determination
  • a compression state determination unit 112 that performs compression state determination
  • a quantization that sets a quantization parameter from the results of scene change determination, scene complexity determination, and compression state determination
  • a parameter setting unit 113 is included.
  • the LCD I / F 107 is an interface that outputs signals for displaying the above-described menus and images to the LCD 108 under the control of the control processing circuit 106.
  • FIG. 2 is a flowchart showing a control procedure for acquiring the complexity of the image and determining the scene complexity.
  • FIG. 3 is a flowchart showing a control procedure for acquiring the amount of motion of an image and performing scene change determination.
  • FIG. 4 is a flowchart showing a control procedure for acquiring the compression rate and determining the compression state.
  • FIG. 5 is a flowchart illustrating a control procedure for acquiring the code amount and determining the compression state.
  • FIG. 6 is a flowchart showing a control procedure for acquiring the bit rate and determining the compression state.
  • FIG. 7 is a flowchart showing a control procedure for setting the quantization parameter.
  • FIG. 8 is another flowchart showing a control procedure for setting the quantization parameter.
  • the first quantization parameter setting method will be described.
  • the compression rate is used as the determination of the compression state.
  • the scene complexity determination unit 114 sets the image complexity (for example, the image encoded immediately before or the target of encoding in S201 of FIG. 2 as the image information in the immediately previous encoding. (The result of adding the absolute value of the difference between the average pixel value of each image and the pixel value of each pixel for all pixels) from the compression processing circuit 105, and the first threshold value with which the complexity of the acquired image is predetermined If it is greater than (for example, 100) (YES in S202), the scene is determined to be complex (S203). On the other hand, if the degree of complexity of the acquired image is equal to or less than a first threshold value (NO in S202), the scene is It is determined as monotonous (S204).
  • the image complexity for example, the image encoded immediately before or the target of encoding in S201 of FIG. 2 as the image information in the immediately previous encoding.
  • the scene change determination unit 111 uses the image motion amount (for example, the absolute value of the difference between the pixel values at the same position in the previous image and the current image) in S301 in FIG. Is obtained from the compression processing circuit 105, and if the amount of motion of the acquired image is greater than a predetermined second threshold (eg, 100) (YES in S302), it is determined that there is a scene change. (S303) When the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), it is determined that there is no scene change (S304).
  • a predetermined second threshold eg, 100
  • the compression state determination unit 112 compresses the compression rate (ratio of the bit amount of the image before encoding to the bit amount of the image after encoding) as the compression processing information in the previous encoding in S401 of FIG. If the acquired compression rate is greater than a predetermined third threshold (for example, 30) (YES in S402), it is determined that the compression state is high (S403), while the acquired compression rate is determined in advance. If it is equal to or less than the set third threshold (NO in S402), it is determined that the compression state is low (S404).
  • a predetermined third threshold for example, 30
  • the quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression state in S701, S702, and S703 of FIG. Confirming the result of the determination of the compression state by the determination unit 112, if it is determined that there is a scene change, the scene is complex, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased.
  • a predetermined first value for example, 2 is added to the quantization parameter for the next compression (S704), and the quantization parameter after the addition is set in the compression processing circuit 105. As a result, the amount of code after compression is reduced and code amount over is not caused.
  • the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
  • the quantization parameter at the next compression is calculated using the compression rate, the image complexity, and the image motion amount acquired from the compression processing circuit 105.
  • the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
  • the second quantization parameter setting method will be described.
  • the code amount is used as the determination of the compression state.
  • the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
  • a predetermined first threshold value for example, 100
  • the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303), and if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), the scene changes It is determined that there is none (S304).
  • two thresholds for example, 100
  • NO in S302 a predetermined second threshold
  • the compression state determination unit 112 acquires the code amount (bit amount of the image after encoding) from the compression processing circuit 105 in S501 of FIG. 5 as the compression processing information in the immediately preceding encoding, and acquires the acquired code amount. Is smaller than a predetermined third threshold (for example, 30 KBytes) (YES in S502), it is determined that the compression state is high (S503). On the other hand, if the obtained code amount is equal to or larger than a predetermined third threshold (in S502) NO), a low compression state is determined (S504).
  • a predetermined third threshold for example, 30 KBytes
  • the quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression in S701, S702, and S703 of FIG. The result of the compression state determination by the state determination unit 112 is confirmed, and when it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased.
  • a predetermined first value for example, 2 is added to the quantization parameter for the next compression (S704), and the added quantization parameter is set in the compression processing circuit 105. By doing so, the code amount after compression is reduced, and the code amount over is not generated.
  • the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
  • the quantization parameter at the next compression is calculated using the code amount, the image complexity, and the image motion amount acquired from the compression processing circuit 105.
  • the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
  • the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
  • a predetermined first threshold value for example, 100
  • the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303). On the other hand, if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), It is determined that there is no scene change (S304).
  • two thresholds for example, 100
  • NO in S302 a predetermined second threshold
  • the compression state determination unit 112 compresses the bit rate (transfer bit amount per unit time when the encoded image is output serially) in S601 of FIG. 6 as the compression processing information in the immediately preceding encoding. If the acquired bit rate is smaller than a predetermined fifth threshold (for example, 12 Mbps) (YES in S602), it is determined that the compression state is high (S603), while the acquired bit rate is determined in advance. If it is equal to or greater than the set fifth threshold (NO in S602), it is determined that the compression state is low (S604).
  • a predetermined fifth threshold for example, 12 Mbps
  • the quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression in S701, S702, and S703 of FIG. The result of the compression state determination by the state determination unit 112 is confirmed, and when it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased.
  • a predetermined first value for example, 2 is added to the quantization parameter for the next compression (S704), and the added quantization parameter is set in the compression processing circuit 105. By doing so, the code amount after compression is reduced, and the code amount over is not generated.
  • the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
  • the quantization parameter at the next compression is calculated using the bit rate, the complexity of the image, and the amount of motion of the image acquired from the compression processing circuit 105.
  • the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
  • the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
  • a predetermined first threshold value for example, 100
  • the scene change determination unit 111 acquires the image motion amount described above in step S301 in FIG. 3 from the compression processing circuit 105 in units of frames as image information in the immediately preceding encoding.
  • a predetermined second threshold for example, 100
  • the amount of motion of the acquired image is equal to or smaller than a predetermined second threshold (in S302). NO)
  • the compression state determination unit 112 acquires the bit rate described above in step S601 of FIG. 6 from the compression processing circuit 105 as the compression processing information in the immediately preceding encoding, and the acquired bit rate is a fifth threshold ( For example, when it is smaller than 12 Mbps (YES in S602), it is determined that the compression state is high (S603). On the other hand, when the acquired bit rate is equal to or higher than a predetermined fifth threshold (NO in S602), it is determined that the compression state is low. (S604).
  • the quantization parameter setting unit 113 performs the scene change by the scene change determination unit 111, the scene complexity by the scene complexity determination unit 114, and the compression state in S801, S802, and S803 in FIG.
  • the result of the determination of the compression state by the determination unit 112 is confirmed. If it is determined that there is a scene change, the scene is complicated, and the compression state is low, the code amount is determined to increase, and 1 is added to the addition counter.
  • a predetermined first predetermined value for example, a quantization parameter for the next compression
  • the post-compression code amount is reduced by setting the quantization parameter after the addition in the compression processing circuit 105. -Do not generate. Note that the processing in steps S804, S806, and S808 counts the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
  • the quantization parameter setting unit 113 determines that the code amount is decreased, and subtracts 1 from the subtraction counter (S805). Only when the counter becomes larger than a predetermined seventh threshold (for example, 10) (YES in S807), a predetermined second predetermined value (for example, 1) is subtracted from the quantization parameter for the next compression. (S809) By setting the post-subtraction quantization parameter in the compression processing circuit 105, the amount of code after compression is increased and image quality deterioration is suppressed.
  • a predetermined seventh threshold for example, 10
  • a predetermined second predetermined value for example, 1
  • steps S805, S807, and S809 count the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
  • the bit rate, the complexity of the image, and the amount of motion of the image acquired from the compression processing circuit 105 are used for the next compression in units of frames.
  • the conversion parameter it is possible to avoid occurrence of code amount over even in a scene where code amount over has occurred in the past.
  • the quantization parameter of the next GOP is set in units of GOP (Group of Pictures).
  • the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
  • a predetermined first threshold value for example, 100
  • the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303). On the other hand, if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), It is determined that there is no scene change (S304).
  • two thresholds for example, 100
  • NO in S302 a predetermined second threshold
  • the compression state determination unit 112 acquires the bit rate described above in step S601 of FIG. 6 from the compression processing circuit 105 as the compression processing information in the immediately preceding encoding, and the acquired bit rate is a fifth threshold ( For example, when it is smaller than 12 Mbps (YES in S602), it is determined that the compression state is high (S603). On the other hand, when the acquired bit rate is equal to or higher than a predetermined fifth threshold (NO in S602), it is determined that the compression state is low. (S604).
  • the quantization parameter setting unit 113 performs the scene change by the scene change determination unit 111, the scene complexity by the scene complexity determination unit 114, and the compression state in S801, S802, and S803 in FIG.
  • the determination result of the compression state by the determination unit 112 is confirmed. If it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount is increased, and 1 is added to the addition counter ( S804) Only when the addition counter becomes larger than a predetermined sixth threshold value (for example, 5) (YES in S806), a predetermined first predetermined value (for example, 2 for the quantization parameter for the next compression).
  • a predetermined sixth threshold value for example, 5
  • a predetermined first predetermined value for example, 2 for the quantization parameter for the next compression.
  • steps S804, S806, and S808 counts the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
  • the quantization parameter setting unit 113 determines that the code amount is decreased, and subtracts 1 from the subtraction counter (S805), Only when the subtraction counter becomes larger than a predetermined seventh threshold value (for example, 10) (YES in S807), a predetermined second predetermined value (for example, 1) is subtracted from the quantization parameter for the next compression.
  • a predetermined seventh threshold value for example, 10
  • a predetermined second predetermined value for example, 1 is subtracted from the quantization parameter for the next compression.
  • the post-subtraction quantization parameter is set in the compression processing circuit 105, thereby increasing the amount of code after compression and suppressing image quality deterioration.
  • steps S805, S807, and S809 count the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
  • the quantum for the next compression is calculated in GOP units.
  • the conversion parameter it is possible to avoid occurrence of code amount over even in a scene where code amount over has occurred in the past.
  • the image processing apparatus and the camera system according to the present invention have an effect that it is possible to prevent the code amount from being excessive when the image is compressed without increasing the cost, and the still camera shown in FIG. This is useful as a video camera or the like shown in FIG.
  • the image processing apparatus and the camera system according to the present invention have been described based on the embodiment.
  • the present invention is not limited to this embodiment.
  • a form obtained by subjecting the present embodiment to various modifications conceived by those skilled in the art, and a part of the first to fifth quantization parameter setting methods in the present embodiment A quantization parameter setting method realized by arbitrarily combining these procedures is also included in the present invention.
  • the control processing circuit 106 has determined all of the compression state determination, the scene change determination, and the scene complexity determination.
  • the present invention is not limited to at least one of these three determinations (or Any combination). Even in the case of at least one determination, since the quantization parameter at the time of the next encoding is set depending on the compression processing information or the image information in the previous encoding in the compression processing circuit 105, in the conventional case, the code This is because the occurrence of the code amount over can be avoided even in a scene where the amount over has occurred.
  • the image processing apparatus and the camera system according to the present invention have an effect that it is possible to prevent the code amount from being excessive when the image is compressed without increasing the cost, such as a camera system such as a still camera or a video camera. Useful as.
  • Solid-state imaging device 102 ... AFE 103 ... Image processing circuit 104 ... Memory 105 ... Compression processing circuit 106 ... Control processing circuit 107 ... LCD I / F 108 ... LCD DESCRIPTION OF SYMBOLS 109 ... Camera system 110 ... Image processing apparatus 111 ... Scene change determination part 112 ... Compression state determination part 113 ... Quantization parameter setting part 114 ... Scene complexity determination part

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Abstract

Disclosed is an image processing device capable of avoiding excess of the amount of code even in a case where excess of the amount of code would have occurred. Specifically disclosed is an image processing device (110) which comprises an image processing circuit (103) that generates brightness data and color difference data of images; a compression processing circuit (105) that acquires the generated brightness data and the color difference data as input images, sets an compression ratio, and performs encoding including quantization on the input images in accordance with the set compression ratio; and a control processing circuit (106) that acquires at least one of compression process information and image information generated at the compression processing circuit (105) during the last encoding from the compression processing circuit (105), performs at least one of compression state determination regarding the compression state during encoding, scene change determination regarding whether or not a scene change occurs in the input images, and scene complexity determination regarding the complexity of the input images, and sets quantization parameters for the next encoding at the compression processing circuit (105) on the basis of the determination result.

Description

画像処理装置及びカメラシステムImage processing apparatus and camera system
　本発明は、画像処理装置及びその画像処理装置を備えたカメラシステムに係り、特に、画像圧縮時の量子化パラメータを補正する機能を有したカメラシステムに関するものである。 The present invention relates to an image processing apparatus and a camera system including the image processing apparatus, and more particularly to a camera system having a function of correcting a quantization parameter at the time of image compression.
　主に動画を撮像するデジタルビデオカメラや主に静止画を撮像するデジタルスチルカメラが広く用いられている。これらの中には、動画と静止画の両方の撮像が可能なものも提供されている。また、デジタルカメラ機能を備えたいわゆるカメラ付き携帯電話端末やカメラ付き携帯電子手帳なども広く利用されるようになってきている。 Digital video cameras that mainly capture moving images and digital still cameras that primarily capture still images are widely used. Some of these are capable of capturing both moving images and still images. In addition, so-called camera-equipped mobile phone terminals equipped with a digital camera function, camera-equipped portable electronic notebooks, and the like have been widely used.
　これらデジタルカメラやカメラ付き携帯電話端末などの撮像機能を備えた機器においては、撮像して得た動画データや静止画データはデータ量が多く、記録容量が有限である記録メディア（記憶媒体）にそのまま記録したのでは、すぐに記録メディアの記録容量がいっぱいになってしまう。このため、撮像して画像データを記憶媒体に記録する場合には種々の方式でデータ圧縮処理してデータ量を減らすようにしてから、記憶媒体に記録するようにしている。例えば、記録対象の画像データが動画データである場合には、ＭＰＥＧ（Ｍｏｖｉｎｇ　Ｐｉｃｔｕｒｅ　Ｅｘｐｅｒｔｓ　Ｇｒｏｕｐ）方式などのデータ圧縮方式が用いられ、記録対象の画像データが静止画データである場合には、ＪＰＥＧ（Ｊｏｉｎｔ　Ｐｈｏｔｏｇｒａｐｈｉｃ　Ｅｘｐｅｒｔｓ　Ｇｒｏｕｐ）方式などのデータ圧縮方式が用いられている。 In devices equipped with an imaging function, such as these digital cameras and camera-equipped mobile phone terminals, moving image data and still image data obtained by imaging are recorded on a recording medium (storage medium) with a large amount of data and a limited recording capacity. If it is recorded as it is, the recording capacity of the recording medium will be full immediately. For this reason, when imaging and recording image data on a storage medium, data compression processing is performed by various methods to reduce the amount of data and then recording on the storage medium. For example, when the image data to be recorded is moving image data, a data compression method such as the MPEG (Moving Picture Experts Group) method is used. When the image data to be recorded is still image data, JPEG ( Data compression methods such as the Joint Photographic Experts Group method are used.
　従来の画像圧縮装置は、静止画データを例えばＪＰＥＧ方式でデータ圧縮する従来の装置において、段階的に所定のデータサイズにまで画像を圧縮するようにしている（例えば、特許文献１参照）。 A conventional image compression apparatus compresses an image to a predetermined data size in a stepwise manner in a conventional apparatus that compresses still image data using, for example, the JPEG method (see, for example, Patent Document 1).
特開２００３－１７９９２６号公報JP 2003-179926 A
　しかしながら、適切な圧縮率を得るためには、複数回の圧縮処理を行うようにしているので（圧縮処理の再試行を繰り返すようにしているので）、圧縮処理にかかる時間が長くなる。このため、従来の画像圧縮装置を用いたカメラシステムの場合には、撮像して記録する画像データの圧縮処理に時間がかかるために、撮像間隔を短く設定できないという問題がある。また、圧縮処理を数回繰り返す際には、元画像の全データを保持しておく大容量のメモリが必要となる。一方、ただ１度の圧縮処理によって所定のデータサイズに抑えるためには、圧縮率を高めに設定する必要があり、必要以上に圧縮率を高めるとデータサイズは所定のサイズ内に収まるが、その反面、いわゆるブロックノイズやモスキートノイズの要因となり、再生画像の質を低下させてしまうことにもなりかねない。またシーンチェンジ等により、前回圧縮した画像と現在圧縮する画像とで相関が無くなってしまった場合、圧縮後の符号量が増大し、規格上限の符号量を超えてしまうと、そのフレームを破棄しなければならない。 However, in order to obtain an appropriate compression rate, the compression process is performed a plurality of times (since the retry of the compression process is repeated), the time required for the compression process becomes long. For this reason, in the case of a camera system using a conventional image compression apparatus, since it takes time to compress image data to be captured and recorded, there is a problem that the imaging interval cannot be set short. Further, when the compression process is repeated several times, a large-capacity memory that holds all data of the original image is required. On the other hand, in order to keep the compression rate to a predetermined data size by a single compression process, it is necessary to set the compression rate higher. If the compression rate is increased more than necessary, the data size falls within the predetermined size. On the other hand, it may cause so-called block noise and mosquito noise, which may reduce the quality of the reproduced image. Also, if there is no correlation between the previously compressed image and the currently compressed image due to a scene change, etc., the code amount after compression increases, and if the code amount exceeds the upper limit of the standard, the frame is discarded. There must be.
　つまり、前記従来の画像処理装置では、シーンチェンジ等により前回圧縮した画像との相関が無くなった場合、圧縮後の符号量が増大してしまうため、符号量オーバーとなりそのフレームを破棄しなければならず、動画像が一時的に停止してしまう問題も起きてしまうという課題がある。 That is, in the conventional image processing apparatus, when there is no correlation with the previously compressed image due to a scene change or the like, the code amount after compression increases, so the code amount is over and the frame must be discarded. However, there is a problem that the moving image temporarily stops.
　そこで、本発明は、従来であれば符号量オーバーが発生していたシーンであっても、符号量オーバーの発生を回避できる画像処理装置及びカメラシステムを提供することを目的とする。 Therefore, an object of the present invention is to provide an image processing apparatus and a camera system that can avoid the occurrence of code amount over even in a scene where code amount over has occurred conventionally.
　上記目的を達成するために、第一の発明に係る画像処理装置は、撮像素子から画像を取得し、取得した画像の輝度データ及び色差データを生成する画像処理回路と、前記画像処理回路で生成された輝度データ及び色差データを入力画像として取得し、圧縮率を設定し、設定した圧縮率に従って、前記入力画像に対して、量子化を含む符号化をする圧縮処理回路と、前記圧縮処理回路における直前の符号化で生成された、当該符号化に関する情報である圧縮処理情報及び符号化された画像に関する情報である画像情報の少なくとも一つを前記圧縮処理回路から取得し、取得した前記圧縮処理情報及び画像情報の少なくとも一つから、前記符号化における圧縮状態に関する判定である圧縮状態判定、前記入力画像においてシーン変化が生じたか否かに関する判定であるシーン変化判定、及び、前記入力画像の複雑度に関する判定であるシーン複雑度判定の少なくとも一つの判定を行い、その判定結果より、前記圧縮処理回路における次回の符号化時の量子化パラメータを設定する制御処理回路とを備えた画像処理装置である。 In order to achieve the above object, an image processing apparatus according to a first aspect of the present invention acquires an image from an image sensor and generates luminance data and color difference data of the acquired image, and the image processing circuit generates the image processing circuit. A compression processing circuit that obtains the luminance data and color difference data as an input image, sets a compression rate, and performs encoding including quantization on the input image according to the set compression rate, and the compression processing circuit At least one of the compression processing information that is information related to the encoding and the image information that is information related to the encoded image generated by the previous encoding in the above is acquired from the compression processing circuit, and the acquired compression processing Whether at least one of the information and the image information is a compression state determination that is a determination regarding the compression state in the encoding, whether a scene change has occurred in the input image At least one of a scene change determination that is a determination related to the above and a scene complexity determination that is a determination related to the complexity of the input image, and a quantum at the time of the next encoding in the compression processing circuit is determined based on the determination result. And an image processing apparatus including a control processing circuit for setting a conversion parameter.
　かかる構成により、前回圧縮した画像との相関が無くなった場合でも、事前に量子化パラメータを適切な値に設定することになり、符号量が増大してしまう問題を防ぐことができる。 With this configuration, even when there is no correlation with the previously compressed image, the quantization parameter is set to an appropriate value in advance, and the problem that the code amount increases can be prevented.
　なお、量子化パラメータとは、量子化ステップに対応したパラメータであり、量子化ステップが大きい程大きな値をとる。 It should be noted that the quantization parameter is a parameter corresponding to the quantization step, and takes a larger value as the quantization step is larger.
　また、本第二の発明の画像処理装置は、第一の発明に対して、前記圧縮処理回路から取得する前記圧縮処理情報を圧縮率とし、取得した前記圧縮率を予め定められた閾値と比較することで前記圧縮状態判定を行うことを特徴とした画像処理装置である。 The image processing apparatus according to the second aspect of the present invention uses the compression processing information acquired from the compression processing circuit as a compression rate relative to the first invention, and compares the acquired compression rate with a predetermined threshold value. By doing so, the compressed state determination is performed.
　かかる構成により、圧縮率より圧縮状態を判定し、量子化パラメータを変更することができる。 With this configuration, it is possible to determine the compression state from the compression rate and change the quantization parameter.
　また、本第三の発明の画像処理装置は、第一の発明に対して、前記圧縮処理回路から取得する前記圧縮処理情報を前記圧縮処理回路での符号化における符号量とし、取得した前記符号量を予め定められた閾値と比較することで前記圧縮状態判定を行うことを特徴とした画像処理装置である。 The image processing apparatus according to the third aspect of the invention provides the code obtained by using the compression processing information acquired from the compression processing circuit as a code amount in encoding by the compression processing circuit, as compared to the first invention. In the image processing apparatus, the compression state determination is performed by comparing the amount with a predetermined threshold value.
　かかる構成により、符号量より圧縮状態を判定し、量子化パラメータを変更することができる。 With this configuration, it is possible to determine the compression state from the code amount and change the quantization parameter.
　また、本第四の発明の画像処理装置は、第一の発明に対して、前記圧縮処理回路から取得する前記圧縮処理情報を前記圧縮処理回路での符号化によって生成された符号のビットレートとし、取得した前記ビットレートを予め定められた閾値と比較することで前記圧縮状態判定を行うことを特徴とした画像処理装置である。 Further, the image processing apparatus according to the fourth aspect of the invention provides the bit rate of the code generated by the encoding in the compression processing circuit as the compression processing information acquired from the compression processing circuit in the first invention. The image processing apparatus is characterized in that the compression state determination is performed by comparing the acquired bit rate with a predetermined threshold value.
　かかる構成により、ビットレートより圧縮状態を判定し、量子化パラメータを変更することができる。 With this configuration, it is possible to determine the compression state from the bit rate and change the quantization parameter.
　また、本第五の発明の画像処理装置は、第一～四の発明に対して、前記圧縮処理回路から取得する前記画像情報として画像の複雑度を取得し、取得した画像の複雑度を予め定められた閾値と比較することで、前記シーン複雑度判定を行うことを特徴とした画像処理装置である。 The image processing apparatus according to the fifth aspect of the present invention acquires the complexity of the image as the image information acquired from the compression processing circuit, and previously sets the complexity of the acquired image to the first to fourth aspects of the invention. The image processing apparatus is characterized in that the scene complexity determination is performed by comparing with a predetermined threshold value.
　かかる構成により、画像の複雑度よりシーンを判定し、量子化パラメータを変更することができる。 With this configuration, it is possible to determine a scene from the complexity of the image and change the quantization parameter.
　また、本第六の発明の画像処理装置は、第一～四の発明に対して、前記圧縮処理回路から取得する前記画像情報として画像の動き量を取得し、取得した画像の動き量を予め定められた閾値と比較することで、前記シーン変化判定を行うことを特徴とした画像処理装置である。 The image processing apparatus according to the sixth aspect of the invention obtains the amount of motion of the image as the image information obtained from the compression processing circuit in the first to fourth aspects of the invention, and sets the amount of motion of the obtained image in advance. The image processing apparatus is characterized in that the scene change determination is performed by comparing with a predetermined threshold value.
　かかる構成により、画像の動き量よりシーンを判定し、量子化パラメータを変更することができる。 With this configuration, it is possible to determine the scene from the amount of motion of the image and change the quantization parameter.
　また、本第七の発明の画像処理装置は、第一の発明に対して、フレーム単位で次フレームの量子化パラメータを設定することを特徴とした画像処理装置である。 The image processing apparatus according to the seventh aspect of the invention is an image processing apparatus characterized in that the quantization parameter of the next frame is set in units of frames as compared with the first aspect of the invention.
　かかる構成により、圧縮率状態判定、シーン判定の結果よりシーンを判定し、フレーム単位で量子化パラメータを変更することができる。 With this configuration, it is possible to determine a scene from the result of compression rate state determination and scene determination, and change the quantization parameter in units of frames.
　また、本第八の発明の画像処理装置は、第一の発明に対して、ＧＯＰ（Ｇｒｏｕｐ　ｏｆ　Ｐｉｃｔｕｒｅ）単位で次ＧＯＰの量子化パラメータを設定することを特徴とした画像処理装置である。 The image processing apparatus according to the eighth aspect of the invention is an image processing apparatus characterized in that the quantization parameter of the next GOP is set in GOP (Group of Picture) units as compared with the first aspect of the invention.
　かかる構成により、圧縮率状態判定、シーン判定の結果よりシーンを判定し、ＧＯＰ単位で量子化パラメータを変更することができる。 With this configuration, it is possible to determine a scene from the result of compression rate state determination and scene determination, and change the quantization parameter in GOP units.
　また、本第九の発明の画像処理装置は、第一、七または八の発明に対して、シーン判定有り、かつ、低圧縮状態が連続したときに量子化パラメータを一定値加算することで量子化ステップを増加させることを特徴とした画像処理装置である。 The image processing apparatus according to the ninth aspect of the present invention, in contrast to the first, seventh or eighth aspect, adds a constant value to the quantization parameter when there is a scene determination and the low compression state continues. An image processing apparatus characterized in that the number of steps is increased.
　かかる構成により、複雑な画像が連続したときに量子化パラメータを一定値加算することで量子化ステップを大きくし、発生符号量を抑制することができる。 With this configuration, it is possible to increase the quantization step by adding a constant value to the quantization parameter when complex images are continuous, and to suppress the generated code amount.
　また、本第十の発明の画像処理装置は、第一、七または八の発明に対して、シーン判定無し、または、高圧縮状態が連続したときに量子化パラメータを一定値減算することで量子化ステップを減少させることを特徴とした画像処理装置である。 The image processing apparatus according to the tenth aspect of the present invention, in contrast to the first, seventh, or eighth aspect, performs a quantum subtraction by subtracting a constant value from the quantization parameter when there is no scene determination or when a high compression state continues. An image processing apparatus characterized in that the number of steps is reduced.
　かかる構成により、単調な画像が連続したときに量子化パラメータを一定値減算することで量子化ステップを小さくし、画質劣化を抑制することができる。 With this configuration, it is possible to reduce the quantization step by subtracting a constant value from the quantization parameter when monotonic images are continuous, and to suppress image quality deterioration.
　また、本第十一の発明の画像処理装置は、第一、七または八の発明に対して、シーン判定有り、かつ、低圧縮状態をカウントし、そのカウント値が一定値の閾値を超えたときに量子化パラメータを一定値加算することで量子化ステップを増加させることを特徴とした画像処理装置である。 In addition, the image processing apparatus according to the eleventh aspect of the present invention has a scene determination and counts a low compression state with respect to the first, seventh or eighth invention, and the count value exceeds a certain threshold value. An image processing apparatus characterized in that the quantization step is sometimes increased by adding a constant value to the quantization parameter.
　かかる構成により、複雑な画像かつ低圧縮状態の回数が一定値の閾値を超えたときに量子化パラメータを一定値加算することで量子化ステップを大きくし、発生符号量を抑制することができる。 With this configuration, it is possible to increase the quantization step by adding a constant quantization parameter when the number of complicated images and the number of low compression states exceeds a certain threshold value, thereby suppressing the amount of generated code.
　また、本第十二の発明の画像処理装置は、第一、七または八の発明に対して、シーン判定無し、または、高圧縮状態をカウントし、そのカウント値が一定値の閾値を超えたときに量子化パラメータを一定値減算することで量子化ステップを減少させることを特徴とした画像処理装置である。 The image processing apparatus according to the twelfth aspect of the invention counts no scene determination or a high compression state with respect to the first, seventh or eighth invention, and the count value exceeds a predetermined threshold value. An image processing apparatus characterized in that a quantization step is sometimes reduced by subtracting a constant value from a quantization parameter.
　かかる構成により、単調な画像または高圧縮状態の回数が一定値の閾値を超えたときに量子化パラメータを一定値減算することで量子化ステップを小さくし、画質劣化を抑制することができる。 With such a configuration, it is possible to reduce the quantization step by subtracting a constant value of the quantization parameter when the number of monotonous images or the number of high compression states exceeds a constant value threshold value, and to suppress image quality deterioration.
　また、本第十三の発明のカメラシステムは、レンズを通して受けた光を電気信号に変換し撮像信号として出力する固体撮像素子と、前記撮像信号をデジタル変換して、デジタル撮像信号を得るアナログ／デジタル変換回路と、前記アナログ／デジタル変換回路から画像を入力し画像処理を行う上記画像処理装置とを具備するカメラシステムである。 The camera system according to the thirteenth aspect of the invention is a solid-state imaging device that converts light received through a lens into an electrical signal and outputs it as an imaging signal; A camera system including a digital conversion circuit and the image processing apparatus that performs image processing by inputting an image from the analog / digital conversion circuit.
　かかる構成により、前回圧縮した画像との相関が無くなった場合でも、事前に量子化パラメータを適切な値に設定することになり、符号量が増大してしまう問題を防ぐことができる。 With this configuration, even when there is no correlation with the previously compressed image, the quantization parameter is set to an appropriate value in advance, and the problem that the code amount increases can be prevented.
　本発明による画像処理装置及びそれを用いたカメラシステムは、前記圧縮処理回路から取得した圧縮率、符号量、ビットレート、画像の複雑度、画像の動き量の少なくとも一つを用いて次回圧縮時の量子化パラメータを算出することで、従来符号量オーバーが発生していたシーンであっても符号量オーバーが発生しない効果を有する。 An image processing apparatus according to the present invention and a camera system using the image processing apparatus at the time of next compression using at least one of a compression rate, a code amount, a bit rate, an image complexity, and an image motion amount acquired from the compression processing circuit. By calculating the quantization parameter, there is an effect that the code amount over does not occur even in a scene where the code amount over has conventionally occurred.
図１は、本発明に係るカメラシステムの全体の構成図である。FIG. 1 is an overall configuration diagram of a camera system according to the present invention. 図２は、画像の複雑度を取得し、シーン複雑度判定を行うフローチャートである。FIG. 2 is a flowchart for acquiring the complexity of the image and determining the scene complexity. 図３は、画像の動き量を取得し、シーン変化判定を行うフローチャートである。FIG. 3 is a flowchart for acquiring a motion amount of an image and determining a scene change. 図４は、圧縮率を取得し、圧縮状態判定を行うフローチャートである。FIG. 4 is a flowchart for acquiring the compression rate and determining the compression state. 図５は、符号量を取得し、圧縮状態判定を行うフローチャートである。FIG. 5 is a flowchart for acquiring the code amount and determining the compression state. 図６は、ビットレートを取得し、圧縮状態判定を行うフローチャートである。FIG. 6 is a flowchart for acquiring the bit rate and determining the compression state. 図７は、量子化パラメータを設定するフローチャートである。FIG. 7 is a flowchart for setting the quantization parameter. 図８は、量子化パラメータを設定する別のフローチャートである。FIG. 8 is another flowchart for setting the quantization parameter. 図９（ａ）及び（ｂ）は、本発明に係るカメラシステムの外観図である。9A and 9B are external views of the camera system according to the present invention.
　以下、本発明に係る画像処理装置及びそれを備えるカメラシステムの実施の形態、より具体的には、符号量増加を抑止する量子化パラメータ設定方法の実施形態について図面を参照して説明する。なお、実施の形態において同じ符号を付した構成要素は同様の動作を行うので、再度の説明を省略する場合がある。 Hereinafter, an embodiment of an image processing apparatus and a camera system including the image processing apparatus according to the present invention, more specifically, an embodiment of a quantization parameter setting method for suppressing an increase in code amount will be described with reference to the drawings. In addition, since the component which attached | subjected the same code | symbol in embodiment performs the same operation | movement, description may be abbreviate | omitted again.
　本実施の形態においては、圧縮処理回路を用いたカメラシステムに係り、特に、圧縮処理回路の圧縮率、符号量、ビットレート、画像の複雑度及び画像の動き量の少なくとも一つを用いて、最適な量子化パラメータを算出する方法について説明する。 In the present embodiment, the present invention relates to a camera system using a compression processing circuit, in particular, using at least one of the compression rate, code amount, bit rate, image complexity, and image motion amount of the compression processing circuit, A method for calculating the optimum quantization parameter will be described.
　図１は本発明のカメラシステムの構成図である。図１においてカメラシステム１０９は、画像を入力するセンサー（固体撮像素子）１０１、アナログ信号をデジタル信号に変換するＡＦＥ（Ａｎａｌｏｇ　Ｆｒｏｎｔ　Ｅｎｄ）１０２、画像処理装置１１０、ＬＣＤ１０８、メモリ１０４を具備する。 FIG. 1 is a block diagram of the camera system of the present invention. In FIG. 1, a camera system 109 includes a sensor (solid-state imaging device) 101 for inputting an image, an AFE (Analog Front End) 102 for converting an analog signal into a digital signal, an image processing device 110, an LCD 108, and a memory 104.
　センサー１０１は、レンズを通して受けた光を電気信号に変換し、アナログの撮像信号として出力するＣＣＤあるいはＣＭＯＳセンサー等の固体撮像素子である。 The sensor 101 is a solid-state imaging device such as a CCD or CMOS sensor that converts light received through a lens into an electrical signal and outputs the signal as an analog imaging signal.
　ＡＦＥ１０２は、センサー１０１から出力されるアナログ信号をデジタル信号に変換するＡ／Ｄ変換器等である。 The AFE 102 is an A / D converter that converts an analog signal output from the sensor 101 into a digital signal.
　メモリ１０４は、圧縮前、及び、圧縮後の画像を保持するためのメモリであり、例えば、着脱可能な不揮発性のメモリである。 The memory 104 is a memory for holding images before and after compression, and is, for example, a detachable nonvolatile memory.
　ＬＣＤ（Ｌｉｑｕｉｄ　Ｃｒｙｓｔａｌ　Ｄｉｓｐｌａｙ）１０８は、このカメラシステム１０９の操作者と対話するためのメニューや撮像された画像を表示する液晶ディスプレイである。 An LCD (Liquid Crystal Display) 108 is a liquid crystal display that displays a menu for interacting with an operator of the camera system 109 and a captured image.
　画像処理装置１１０は、センサー１０１で得られた画像を圧縮してメモリ１０４に格納したり、メモリ１０４から画像を読み出してＬＣＤ１０８に表示したり、ＬＣＤ１０８を介して操作者と対話したりする１チップのＬＳＩ等である。この画像処理装置１１０は、画像処理回路１０３、圧縮処理回路１０５、制御処理回路１０６及びＬＣＤ　Ｉ／Ｆ（インタフェース）１０７を備える。 The image processing apparatus 110 compresses the image obtained by the sensor 101 and stores the compressed image in the memory 104, reads the image from the memory 104 and displays the image on the LCD 108, or interacts with the operator via the LCD 108. LSI or the like. The image processing apparatus 110 includes an image processing circuit 103, a compression processing circuit 105, a control processing circuit 106, and an LCD I / F (interface) 107.
　画像処理回路１０３は、センサー１０１で得られた画像を、ＡＦＥ１０２を介して取得し、取得した画像から輝度データ及び色差データを生成し、メモリ１０４に格納する回路である。 The image processing circuit 103 is a circuit that acquires an image obtained by the sensor 101 via the AFE 102, generates luminance data and color difference data from the acquired image, and stores them in the memory 104.
　圧縮処理回路１０５は、画像処理回路で生成されメモリ１０４に格納された輝度データ及び色差データを入力画像として取得し、圧縮率を設定し、設定した圧縮率に従って、取得した入力画像に対して、ＭＰＥＧ規格に従ったＤＣＴ変換及び量子化を含む符号化(圧縮処理)をする回路である。 The compression processing circuit 105 acquires luminance data and color difference data generated by the image processing circuit and stored in the memory 104 as an input image, sets a compression rate, and performs the acquired input image according to the set compression rate. This is a circuit that performs encoding (compression processing) including DCT conversion and quantization according to the MPEG standard.
　制御処理回路１０６は、圧縮処理回路１０５での直前の符号化における、当該符号化に関する情報である圧縮処理情報（圧縮率、符号量、ビットレート等）及び符号化された画像に関する情報である画像情報（画像の複雑度、動き量等）の少なくとも一つを圧縮処理回路１０５から取得し、取得した圧縮処理情報及び画像情報の少なくとも一つから、圧縮処理回路１０５での符号化における圧縮状態に関する判定である圧縮状態判定、入力画像においてシーン変化が生じたか否かに関する判定であるシーン変化判定、及び、入力画像の複雑度に関する判定であるシーン複雑度判定の少なくとも一つの判定を行い、その判定結果より、圧縮処理回路１０５における次回の符号化時の量子化パラメータを設定する回路である。なお、本実施の形態では、この制御処理回路１０６は、圧縮状態判定、シーン変化判定、及び、シーン複雑度判定のすべてを行う機能を有し、そのために、シーン変化判定を行うシーン変化判定部１１１、シーン複雑度判定を行うシーン複雑度判定部１１４、圧縮状態判定を行う圧縮状態判定部１１２、それらシーン変化判定、シーン複雑度判定及び圧縮状態判定の結果から量子化パラメータを設定する量子化パラメータ設定部１１３を有する。 The control processing circuit 106 is compression processing information (compression rate, code amount, bit rate, etc.) that is information related to the encoding in the previous encoding in the compression processing circuit 105, and an image that is information related to the encoded image. At least one of information (complexity of image, amount of motion, etc.) is acquired from the compression processing circuit 105, and at least one of the acquired compression processing information and image information is related to a compression state in encoding by the compression processing circuit 105. The determination is performed by at least one of a compression state determination that is a determination, a scene change determination that is a determination regarding whether or not a scene change has occurred in the input image, and a scene complexity determination that is a determination regarding the complexity of the input image. Based on the result, the compression processing circuit 105 sets a quantization parameter for the next encoding. In the present embodiment, the control processing circuit 106 has a function of performing all of the compression state determination, the scene change determination, and the scene complexity determination. For this purpose, a scene change determination unit that performs a scene change determination. 111, a scene complexity determination unit 114 that performs scene complexity determination, a compression state determination unit 112 that performs compression state determination, and a quantization that sets a quantization parameter from the results of scene change determination, scene complexity determination, and compression state determination A parameter setting unit 113 is included.
　ＬＣＤ　Ｉ／Ｆ１０７は、制御処理回路１０６による制御の下で、ＬＣＤ１０８に対して、上述したメニューや画像を表示するための信号を出力するインタフェースである。 The LCD I / F 107 is an interface that outputs signals for displaying the above-described menus and images to the LCD 108 under the control of the control processing circuit 106.
　次に、以上にように構成された本実施の形態におけるカメラシステム１０９における量子化パラメータの設定方法について、フローチャートを用いて説明する。 Next, a method for setting a quantization parameter in the camera system 109 according to the present embodiment configured as described above will be described with reference to a flowchart.
　図２は、画像の複雑度を取得し、シーン複雑度判定を行う制御手順を示すフローチャートである。図３は、画像の動き量を取得し、シーン変化判定を行う制御手順を示すフローチャートである。図４は、圧縮率を取得し、圧縮状態判定を行う制御手順を示すフローチャートである。図５は、符号量を取得し、圧縮状態判定を行う制御手順を示すフローチャートである。図６は、ビットレートを取得し、圧縮状態判定を行う制御手順を示すフローチャートである。図７は、量子化パラメータを設定する制御手順を示すフローチャートである。図８は、量子化パラメータを設定する制御手順を示す別のフローチャートである。 FIG. 2 is a flowchart showing a control procedure for acquiring the complexity of the image and determining the scene complexity. FIG. 3 is a flowchart showing a control procedure for acquiring the amount of motion of an image and performing scene change determination. FIG. 4 is a flowchart showing a control procedure for acquiring the compression rate and determining the compression state. FIG. 5 is a flowchart illustrating a control procedure for acquiring the code amount and determining the compression state. FIG. 6 is a flowchart showing a control procedure for acquiring the bit rate and determining the compression state. FIG. 7 is a flowchart showing a control procedure for setting the quantization parameter. FIG. 8 is another flowchart showing a control procedure for setting the quantization parameter.
　まず、第１の量子化パラメータ設定方法について説明する。ここでは、圧縮状態の判定として、圧縮率を用いる点に特徴がある。 First, the first quantization parameter setting method will be described. Here, there is a feature in that the compression rate is used as the determination of the compression state.
　制御処理回路１０６では、シーン複雑度判定部１１４は、直前の符号化における画像情報として、図２のＳ２０１にて画像の複雑度（例えば、直前に符号化された画像又は符号化の対象となっている画像の画素値の平均と各画素の画素値との差分の絶対値を全画素について加算した結果）を圧縮処理回路１０５から取得し、取得した画像の複雑度が予め定めた第１閾値（例えば、１００）より大きい場合(Ｓ２０２でＹＥＳ)、シーンが複雑と判定し(Ｓ２０３)、一方、取得した画像の複雑度が予め定めた第１閾値以下の場合(Ｓ２０２でＮＯ)、シーンが単調と判定する(Ｓ２０４)。 In the control processing circuit 106, the scene complexity determination unit 114 sets the image complexity (for example, the image encoded immediately before or the target of encoding in S201 of FIG. 2 as the image information in the immediately previous encoding. (The result of adding the absolute value of the difference between the average pixel value of each image and the pixel value of each pixel for all pixels) from the compression processing circuit 105, and the first threshold value with which the complexity of the acquired image is predetermined If it is greater than (for example, 100) (YES in S202), the scene is determined to be complex (S203). On the other hand, if the degree of complexity of the acquired image is equal to or less than a first threshold value (NO in S202), the scene is It is determined as monotonous (S204).
　また、シーン変化判定部１１１は、直前の符号化における画像情報として、図３のＳ３０１にて画像の動き量（例えば、前の画像と現在の画像における同一位置での画素値の差分の絶対値を全画素について加算した結果）を圧縮処理回路１０５から取得し、取得した画像の動き量が予め定めた第２閾値（例えば、１００）より大きい場合(Ｓ３０２でＹＥＳ)、シーン変化有りと判定し(Ｓ３０３)、取得した画像の動き量が予め定めた第２閾値以下の場合(Ｓ３０２でＮＯ)、シーン変化無しと判定する(Ｓ３０４)。 In addition, the scene change determination unit 111 uses the image motion amount (for example, the absolute value of the difference between the pixel values at the same position in the previous image and the current image) in S301 in FIG. Is obtained from the compression processing circuit 105, and if the amount of motion of the acquired image is greater than a predetermined second threshold (eg, 100) (YES in S302), it is determined that there is a scene change. (S303) When the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), it is determined that there is no scene change (S304).
　また、圧縮状態判定部１１２は、直前の符号化における圧縮処理情報として、図４のＳ４０１にて圧縮率（符号化後の画像のビット量に対する符号化前の画像のビット量の比）を圧縮処理回路１０５から取得し、取得した圧縮率が予め定めた第３閾値（例えば、３０）より大きい場合（Ｓ４０２でＹＥＳ）、高圧縮状態と判定し（Ｓ４０３）、一方、取得した圧縮率が予め定めた第３閾値以下の場合（Ｓ４０２でＮＯ）、低圧縮状態と判定する(Ｓ４０４)。 Further, the compression state determination unit 112 compresses the compression rate (ratio of the bit amount of the image before encoding to the bit amount of the image after encoding) as the compression processing information in the previous encoding in S401 of FIG. If the acquired compression rate is greater than a predetermined third threshold (for example, 30) (YES in S402), it is determined that the compression state is high (S403), while the acquired compression rate is determined in advance. If it is equal to or less than the set third threshold (NO in S402), it is determined that the compression state is low (S404).
　そして、量子化パラメータ設定部１１３は、図７のＳ７０１、Ｓ７０２、Ｓ７０３にて、それぞれ、シーン変化判定部１１１によるシーン変化の判定、シーン複雑度判定部１１４によるシーン複雑度の判定及び、圧縮状態判定部１１２による圧縮状態の判定の結果を確認し、シーン変化有り、かつ、シーンが複雑、かつ、低圧縮状態と判定された場合、符号量が増加すると判断し、量子化ステップを大きくして符号量を削減するために、次回圧縮させるときの量子化パラメータに予め定めた第１所定値（例えば、２）を加算し（Ｓ７０４）、加算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を削減させ、符号量オーバーを発生させないようにする。 Then, the quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression state in S701, S702, and S703 of FIG. Confirming the result of the determination of the compression state by the determination unit 112, if it is determined that there is a scene change, the scene is complex, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased. In order to reduce the code amount, a predetermined first value (for example, 2) is added to the quantization parameter for the next compression (S704), and the quantization parameter after the addition is set in the compression processing circuit 105. As a result, the amount of code after compression is reduced and code amount over is not caused.
　一方、シーン変化無し、または、シーン単調、または、高圧縮状態と判定された場合、量子化パラメータ設定部１１３は、符号量が減少すると判断し、量子化ステップを小さくして符号量を増加させるために、次回圧縮させるときの量子化パラメータに予め定めた第２所定値（例えば、１）を減算し（Ｓ７０５）、減算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を増加させ、画質劣化を抑制させる。 On the other hand, if it is determined that there is no scene change, scene monotony, or a high compression state, the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
　以上のように、本第１の量子化パラメータ設定方法によれば、圧縮処理回路１０５から取得した圧縮率、画像の複雑度、画像の動き量を用いて次回圧縮時の量子化パラメータを算出することで、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生を回避できる。 As described above, according to the first quantization parameter setting method, the quantization parameter at the next compression is calculated using the compression rate, the image complexity, and the image motion amount acquired from the compression processing circuit 105. Thus, the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
　次に、第２の量子化パラメータ設定方法について説明する。ここでは、圧縮状態の判定として、符号量を用いる点に特徴がある。 Next, the second quantization parameter setting method will be described. Here, there is a feature in that the code amount is used as the determination of the compression state.
　制御処理回路１０６では、シーン複雑度判定部１１４は、直前の符号化における画像情報として、図２のＳ２０１にて上述した画像の複雑度を圧縮処理回路１０５から取得し、取得した画像の複雑度が予め定めた第１閾値（例えば、１００）より大きい場合(Ｓ２０２でＹＥＳ)、シーンが複雑と判定し(Ｓ２０３)、一方、取得した画像の複雑度が予め定めた第１閾値以下の場合(Ｓ２０２でＮＯ)、シーンが単調と判定する(Ｓ２０４)。 In the control processing circuit 106, the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
　また、シーン変化判定部１１１は、直前の符号化における画像情報として、図３のＳ３０１にて上述した画像の動き量を圧縮処理回路１０５から取得し、取得した画像の動き量が予め定めた第２閾値（例えば、１００）より大きい場合(Ｓ３０２でＹＥＳ)、シーン変化有りと判定し(Ｓ３０３)、取得した画像の動き量が予め定めた第２閾値以下の場合(Ｓ３０２でＮＯ)、シーン変化無しと判定する(Ｓ３０４)。 In addition, the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303), and if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), the scene changes It is determined that there is none (S304).
　また、圧縮状態判定部１１２は、直前の符号化における圧縮処理情報として、図５のＳ５０１にて符号量（符号化後の画像のビット量）を圧縮処理回路１０５から取得し、取得した符号量が予め定めた第３閾値（例えば、３０ＫＢｙｔｅ）より小さい場合（Ｓ５０２でＹＥＳ）、高圧縮状態と判定し（Ｓ５０３）、一方、取得した符号量が予め定めた第３閾値以上の場合(Ｓ５０２でＮＯ)、低圧縮状態と判定する（Ｓ５０４）。 Further, the compression state determination unit 112 acquires the code amount (bit amount of the image after encoding) from the compression processing circuit 105 in S501 of FIG. 5 as the compression processing information in the immediately preceding encoding, and acquires the acquired code amount. Is smaller than a predetermined third threshold (for example, 30 KBytes) (YES in S502), it is determined that the compression state is high (S503). On the other hand, if the obtained code amount is equal to or larger than a predetermined third threshold (in S502) NO), a low compression state is determined (S504).
　そして、量子化パラメータ設定部１１３は、図７のＳ７０１、Ｓ７０２、Ｓ７０３にて、それぞれ、シーン変化判定部１１１によるシーン変化の判定、シーン複雑度判定部１１４によるシーン複雑度の判定、及び、圧縮状態判定部１１２による圧縮状態の判定の結果を確認し、シーン変化有り、かつ、シーンが複雑、かつ、低圧縮状態と判定された場合、符号量が増加すると判断し、量子化ステップを大きくして符号量を削減するために、次回圧縮させるときの量子化パラメータに予め定めた第１所定値（例えば、２）を加算し（Ｓ７０４）、加算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を削減させ、符号量オーバーを発生させないようにする。 The quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression in S701, S702, and S703 of FIG. The result of the compression state determination by the state determination unit 112 is confirmed, and when it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased. In order to reduce the amount of code, a predetermined first value (for example, 2) is added to the quantization parameter for the next compression (S704), and the added quantization parameter is set in the compression processing circuit 105. By doing so, the code amount after compression is reduced, and the code amount over is not generated.
　一方、シーン変化無し、または、シーン単調、または、高圧縮状態と判定された場合、量子化パラメータ設定部１１３は、符号量が減少すると判断し、量子化ステップを小さくして符号量が増加させるために、次回圧縮させるときの量子化パラメータに予め定めた第２所定値（例えば、１）を減算し(Ｓ７０５)、減算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を増加させ、画質劣化を抑制させる。 On the other hand, if it is determined that there is no scene change, scene monotony, or a high compression state, the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
　以上のように、本第２の量子化パラメータ設定方法によれば、圧縮処理回路１０５から取得した符号量、画像の複雑度、画像の動き量を用いて次回圧縮時の量子化パラメータを算出することで、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生を回避できる。 As described above, according to the second quantization parameter setting method, the quantization parameter at the next compression is calculated using the code amount, the image complexity, and the image motion amount acquired from the compression processing circuit 105. Thus, the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
　次に、第３の量子化パラメータ設定方法について説明する。ここでは、圧縮状態の判定として、ビットレートを用いる点に特徴がある。 Next, a third quantization parameter setting method will be described. Here, there is a feature in that the bit rate is used as the determination of the compression state.
　制御処理回路１０６では、シーン複雑度判定部１１４は、直前の符号化における画像情報として、図２のＳ２０１にて上述した画像の複雑度を圧縮処理回路１０５から取得し、取得した画像の複雑度が予め定めた第１閾値（例えば、１００）より大きい場合(Ｓ２０２でＹＥＳ)、シーンが複雑と判定し(Ｓ２０３)、一方、取得した画像の複雑度が予め定めた第１閾値以下の場合(Ｓ２０２でＮＯ)、シーンが単調と判定する(Ｓ２０４)。 In the control processing circuit 106, the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
　また、シーン変化判定部１１１は、直前の符号化における画像情報として、図３のＳ３０１にて上述した画像の動き量を圧縮処理回路１０５から取得し、取得した画像の動き量が予め定めた第２閾値（例えば、１００）より大きい場合(Ｓ３０２でＹＥＳ)、シーン変化有りと判定し(Ｓ３０３)、一方、取得した画像の動き量が予め定めた第２閾値以下の場合(Ｓ３０２でＮＯ)、シーン変化無しと判定する(Ｓ３０４)。 In addition, the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303). On the other hand, if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), It is determined that there is no scene change (S304).
　また、圧縮状態判定部１１２は、直前の符号化における圧縮処理情報として、図６のＳ６０１にてビットレート（符号化された画像をシリアルに出力する場合の単位時間当たりの転送ビット量）を圧縮処理回路１０５から取得し、取得したビットレートが予め定めた第５閾値（例えば、１２Ｍｂｐｓ）より小さい場合（Ｓ６０２でＹＥＳ）、高圧縮状態と判定し（Ｓ６０３）、一方、取得したビットレートが予め定めた第５閾値以上の場合（Ｓ６０２でＮＯ）、低圧縮状態と判定する(Ｓ６０４)。 In addition, the compression state determination unit 112 compresses the bit rate (transfer bit amount per unit time when the encoded image is output serially) in S601 of FIG. 6 as the compression processing information in the immediately preceding encoding. If the acquired bit rate is smaller than a predetermined fifth threshold (for example, 12 Mbps) (YES in S602), it is determined that the compression state is high (S603), while the acquired bit rate is determined in advance. If it is equal to or greater than the set fifth threshold (NO in S602), it is determined that the compression state is low (S604).
　そして、量子化パラメータ設定部１１３は、図７のＳ７０１、Ｓ７０２、Ｓ７０３にて、それぞれ、シーン変化判定部１１１によるシーン変化の判定、シーン複雑度判定部１１４によるシーン複雑度の判定、及び、圧縮状態判定部１１２による圧縮状態の判定の結果を確認し、シーン変化有り、かつ、シーンが複雑、かつ、低圧縮状態と判定された場合、符号量が増加すると判断し、量子化ステップを大きくして符号量を削減するために、次回圧縮させるときの量子化パラメータに予め定めた第１所定値（例えば、２）を加算し（Ｓ７０４）、加算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を削減させ、符号量オーバーを発生させないようにする。 The quantization parameter setting unit 113 determines the scene change by the scene change determination unit 111, the scene complexity determination by the scene complexity determination unit 114, and the compression in S701, S702, and S703 of FIG. The result of the compression state determination by the state determination unit 112 is confirmed, and when it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount increases, and the quantization step is increased. In order to reduce the amount of code, a predetermined first value (for example, 2) is added to the quantization parameter for the next compression (S704), and the added quantization parameter is set in the compression processing circuit 105. By doing so, the code amount after compression is reduced, and the code amount over is not generated.
　一方、シーン変化無し、または、シーン単調、または、高圧縮状態と判定された場合、量子化パラメータ設定部１１３は、符号量が減少すると判断し、量子化ステップを小さくして符号量を増加させるために、次回圧縮させるときの量子化パラメータに予め定めた第２所定値（例えば、１）を減算し(Ｓ７０５)、減算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を増加させ、画質劣化を抑制させる。 On the other hand, if it is determined that there is no scene change, scene monotony, or a high compression state, the quantization parameter setting unit 113 determines that the code amount is decreased, and decreases the quantization step to increase the code amount. Therefore, a second predetermined value (for example, 1) set in advance is subtracted from the quantization parameter for the next compression (S 705), and the quantization parameter after the subtraction is set in the compression processing circuit 105. The code amount is increased and image quality deterioration is suppressed.
　以上のように、本第３の量子化パラメータ設定方法によれば、圧縮処理回路１０５から取得したビットレート、画像の複雑度、画像の動き量を用いて次回圧縮時の量子化パラメータを算出することで、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生を回避できる。 As described above, according to the third quantization parameter setting method, the quantization parameter at the next compression is calculated using the bit rate, the complexity of the image, and the amount of motion of the image acquired from the compression processing circuit 105. Thus, the occurrence of code amount over can be avoided even in a scene where code amount over has occurred conventionally.
　次に、第４の量子化パラメータ設定方法について説明する。ここでは、フレーム単位で次フレームの量子化パラメータを設定する点に特徴がある。 Next, a fourth quantization parameter setting method will be described. This is characterized in that the quantization parameter of the next frame is set in units of frames.
　制御処理回路１０６では、シーン複雑度判定部１１４は、直前の符号化における画像情報として、図２のＳ２０１にて上述した画像の複雑度を圧縮処理回路１０５から取得し、取得した画像の複雑度が予め定めた第１閾値（例えば、１００）より大きい場合(Ｓ２０２でＹＥＳ)、シーンが複雑と判定し(Ｓ２０３)、一方、取得した画像の複雑度が予め定めた第１閾値以下の場合(Ｓ２０２でＮＯ)、シーンが単調と判定する(Ｓ２０４)。 In the control processing circuit 106, the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
　また、シーン変化判定部１１１は、直前の符号化における画像情報として、フレーム単位で図３のＳ３０１にて上述した画像の動き量を圧縮処理回路１０５から取得し、取得した画像の動き量が予め定めた第２閾値（例えば、１００）より大きい場合(Ｓ３０２でＹＥＳ)、シーン変化有りと判定し(Ｓ３０３)、一方、取得した画像の動き量が予め定めた第２閾値以下の場合(Ｓ３０２でＮＯ)、シーン変化無しと判定する(Ｓ３０４)。 In addition, the scene change determination unit 111 acquires the image motion amount described above in step S301 in FIG. 3 from the compression processing circuit 105 in units of frames as image information in the immediately preceding encoding. When it is larger than a predetermined second threshold (for example, 100) (YES in S302), it is determined that there is a scene change (S303). On the other hand, when the amount of motion of the acquired image is equal to or smaller than a predetermined second threshold (in S302). NO), it is determined that there is no scene change (S304).
　また、圧縮状態判定部１１２は、直前の符号化における圧縮処理情報として、図６のＳ６０１にて上述したビットレートを圧縮処理回路１０５から取得し、取得したビットレートが予め定めた第５閾値（例えば、１２Ｍｂｐｓ）より小さい場合（Ｓ６０２でＹＥＳ）、高圧縮状態と判定し（Ｓ６０３）、一方、取得したビットレートが予め定めた第５閾値以上の場合(Ｓ６０２でＮＯ)、低圧縮状態と判定する(Ｓ６０４)。 In addition, the compression state determination unit 112 acquires the bit rate described above in step S601 of FIG. 6 from the compression processing circuit 105 as the compression processing information in the immediately preceding encoding, and the acquired bit rate is a fifth threshold ( For example, when it is smaller than 12 Mbps (YES in S602), it is determined that the compression state is high (S603). On the other hand, when the acquired bit rate is equal to or higher than a predetermined fifth threshold (NO in S602), it is determined that the compression state is low. (S604).
　そして、量子化パラメータ設定部１１３は、フレーム単位で図８のＳ８０１、Ｓ８０２、Ｓ８０３にて、それぞれ、シーン変化判定部１１１によるシーン変化、シーン複雑度判定部１１４によるシーン複雑度、及び、圧縮状態判定部１１２による圧縮状態の判定の結果を確認し、シーン変化有り、かつ、シーンが複雑、かつ、低圧縮状態と判定された場合、符号量が増加すると判断し、加算カウンタに１を加算し(Ｓ８０４)、加算カウンタが予め定めた第６閾値（例えば、５）より大きくなった場合にだけ（Ｓ８０６でＹＥＳ）、次回圧縮させるときの量子化パラメータに予め定めた第１所定値（例えば、２）を加算し(Ｓ８０８)、加算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を削減させ、符号量オーバーを発生させないようにする。なお、ステップＳ８０４、Ｓ８０６及びＳ８０８での処理は、上記３つ（シーン変化、シーン複雑度及び圧縮状態）の条件を満たした回数をカウントし、そのカウント値が一定値を超えたこと（一定回数を超える繰り返し）を検出するためである。 Then, the quantization parameter setting unit 113 performs the scene change by the scene change determination unit 111, the scene complexity by the scene complexity determination unit 114, and the compression state in S801, S802, and S803 in FIG. The result of the determination of the compression state by the determination unit 112 is confirmed. If it is determined that there is a scene change, the scene is complicated, and the compression state is low, the code amount is determined to increase, and 1 is added to the addition counter. (S804) Only when the addition counter becomes larger than a predetermined sixth threshold (for example, 5) (YES in S806), a predetermined first predetermined value (for example, a quantization parameter for the next compression) (for example, 2) is added (S808), and the post-compression code amount is reduced by setting the quantization parameter after the addition in the compression processing circuit 105. -Do not generate. Note that the processing in steps S804, S806, and S808 counts the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
　一方、シーン変化無し、または、シーン単調、または、高圧縮状態と判定された場合、量子化パラメータ設定部１１３は、符号量が減少すると判断し、減算カウンタに１を減算し(Ｓ８０５)、減算カウンタが予め定めた第７閾値（例えば、１０）より大きくなった場合にだけ（Ｓ８０７でＹＥＳ）、次回圧縮させるときの量子化パラメータに予め定めた第２所定値（例えば、１）を減算し（Ｓ８０９）、減算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を増加させ、画質劣化を抑制させる。なお、ステップＳ８０５、Ｓ８０７及びＳ８０９での処理は、上記３つ（シーン変化、シーン複雑度及び圧縮状態）の条件を満たした回数をカウントし、そのカウント値が一定値を超えたこと（一定回数を超える繰り返し）を検出するためである。 On the other hand, if it is determined that there is no scene change, scene monotony, or a high compression state, the quantization parameter setting unit 113 determines that the code amount is decreased, and subtracts 1 from the subtraction counter (S805). Only when the counter becomes larger than a predetermined seventh threshold (for example, 10) (YES in S807), a predetermined second predetermined value (for example, 1) is subtracted from the quantization parameter for the next compression. (S809) By setting the post-subtraction quantization parameter in the compression processing circuit 105, the amount of code after compression is increased and image quality deterioration is suppressed. Note that the processes in steps S805, S807, and S809 count the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
　以上のように、本第４の量子化パラメータ設定方法によれば、圧縮処理回路１０５から取得したビットレート、画像の複雑度、画像の動き量を用いて、フレーム単位で、次回圧縮時の量子化パラメータを算出することで、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生を回避できる。 As described above, according to the fourth quantization parameter setting method, the bit rate, the complexity of the image, and the amount of motion of the image acquired from the compression processing circuit 105 are used for the next compression in units of frames. By calculating the conversion parameter, it is possible to avoid occurrence of code amount over even in a scene where code amount over has occurred in the past.
　次に、第５の量子化パラメータ設定方法について説明する。ここでは、ＧＯＰ（Ｇｒｏｕｐ　ｏｆ　Ｐｉｃｔｕｒｅ）単位で次ＧＯＰの量子化パラメータを設定する点に特徴がある。 Next, a fifth quantization parameter setting method will be described. Here, there is a feature in that the quantization parameter of the next GOP is set in units of GOP (Group of Pictures).
　制御処理回路１０６では、シーン複雑度判定部１１４は、直前の符号化における画像情報として、図２のＳ２０１にて上述した画像の複雑度を圧縮処理回路１０５から取得し、取得した画像の複雑度が予め定めた第１閾値（例えば、１００）より大きい場合(Ｓ２０２でＹＥＳ)、シーンが複雑と判定し(Ｓ２０３)、一方、取得した画像の複雑度が予め定めた第１閾値以下の場合(Ｓ２０２でＮＯ)、シーンが単調と判定する(Ｓ２０４)。 In the control processing circuit 106, the scene complexity determination unit 114 acquires the image complexity described above in step S201 of FIG. 2 from the compression processing circuit 105 as image information in the previous encoding, and acquires the image complexity. Is larger than a predetermined first threshold value (for example, 100) (YES in S202), it is determined that the scene is complicated (S203). On the other hand, when the complexity of the acquired image is equal to or lower than the predetermined first threshold value ( If NO in S202, the scene is determined to be monotonous (S204).
　また、シーン変化判定部１１１は、直前の符号化における画像情報として、図３のＳ３０１にて上述した画像の動き量を圧縮処理回路１０５から取得し、取得した画像の動き量が予め定めた第２閾値（例えば、１００）より大きい場合(Ｓ３０２でＹＥＳ)、シーン変化有りと判定し(Ｓ３０３)、一方、取得した画像の動き量が予め定めた第２閾値以下の場合(Ｓ３０２でＮＯ)、シーン変化無しと判定する(Ｓ３０４)。 In addition, the scene change determination unit 111 acquires the image motion amount described above in step S301 of FIG. 3 from the compression processing circuit 105 as image information in the immediately preceding encoding, and the acquired image motion amount is determined in advance. If it is larger than two thresholds (for example, 100) (YES in S302), it is determined that there is a scene change (S303). On the other hand, if the amount of motion of the acquired image is equal to or less than a predetermined second threshold (NO in S302), It is determined that there is no scene change (S304).
　また、圧縮状態判定部１１２は、直前の符号化における圧縮処理情報として、図６のＳ６０１にて上述したビットレートを圧縮処理回路１０５から取得し、取得したビットレートが予め定めた第５閾値（例えば、１２Ｍｂｐｓ）より小さい場合（Ｓ６０２でＹＥＳ）、高圧縮状態と判定し（Ｓ６０３）、一方、取得したビットレートが予め定めた第５閾値以上の場合(Ｓ６０２でＮＯ)、低圧縮状態と判定する(Ｓ６０４)。 In addition, the compression state determination unit 112 acquires the bit rate described above in step S601 of FIG. 6 from the compression processing circuit 105 as the compression processing information in the immediately preceding encoding, and the acquired bit rate is a fifth threshold ( For example, when it is smaller than 12 Mbps (YES in S602), it is determined that the compression state is high (S603). On the other hand, when the acquired bit rate is equal to or higher than a predetermined fifth threshold (NO in S602), it is determined that the compression state is low. (S604).
　そして、量子化パラメータ設定部１１３は、ＧＯＰ単位で図８のＳ８０１、Ｓ８０２、Ｓ８０３にて、それぞれ、シーン変化判定部１１１によるシーン変化、シーン複雑度判定部１１４によるシーン複雑度、及び、圧縮状態判定部１１２による圧縮状態の判定結果を確認し、シーン変化有り、かつ、シーンが複雑、かつ、低圧縮状態と判定された場合、符号量が増加すると判断し、加算カウンタに１を加算し(Ｓ８０４)、加算カウンタが予め定めた第６閾値（例えば、５）より大きくなった場合にだけ（Ｓ８０６でＹＥＳ）、次回圧縮させるときの量子化パラメータに予め定めた第１所定値（例えば、２）を加算し（Ｓ８０８）、加算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を削減させ、符号量オーバーを発生させないようにする。なお、ステップＳ８０４、Ｓ８０６及びＳ８０８での処理は、上記３つ（シーン変化、シーン複雑度及び圧縮状態）の条件を満たした回数をカウントし、そのカウント値が一定値を超えたこと（一定回数を超える繰り返し）を検出するためである。 Then, the quantization parameter setting unit 113 performs the scene change by the scene change determination unit 111, the scene complexity by the scene complexity determination unit 114, and the compression state in S801, S802, and S803 in FIG. The determination result of the compression state by the determination unit 112 is confirmed. If it is determined that there is a scene change, the scene is complicated, and the compression state is low, it is determined that the code amount is increased, and 1 is added to the addition counter ( S804) Only when the addition counter becomes larger than a predetermined sixth threshold value (for example, 5) (YES in S806), a predetermined first predetermined value (for example, 2 for the quantization parameter for the next compression). ) Is added (S808), and the quantization parameter after the addition is set in the compression processing circuit 105, so that the amount of code after compression is reduced and the code amount exceeds The so as not to occur. Note that the processing in steps S804, S806, and S808 counts the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
　一方、シーン変化無し、または、シーンが単調、または、高圧縮状態と判定された場合、量子化パラメータ設定部１１３は、符号量が減少すると判断し、減算カウンタに１を減算し（Ｓ８０５）、減算カウンタが予め定めた第７閾値（例えば、１０）より大きくなった場合にだけ（Ｓ８０７でＹＥＳ）、次回圧縮させるときの量子化パラメータに予め定めた第２所定値（例えば、１）を減算し（Ｓ８０９）、減算後の量子化パラメータを圧縮処理回路１０５に設定することで圧縮後の符号量を増加させ、画質劣化を抑制させる。なお、ステップＳ８０５、Ｓ８０７及びＳ８０９での処理は、上記３つ（シーン変化、シーン複雑度及び圧縮状態）の条件を満たした回数をカウントし、そのカウント値が一定値を超えたこと（一定回数を超える繰り返し）を検出するためである。 On the other hand, if it is determined that there is no scene change, or the scene is monotonous or in a highly compressed state, the quantization parameter setting unit 113 determines that the code amount is decreased, and subtracts 1 from the subtraction counter (S805), Only when the subtraction counter becomes larger than a predetermined seventh threshold value (for example, 10) (YES in S807), a predetermined second predetermined value (for example, 1) is subtracted from the quantization parameter for the next compression. In step S809, the post-subtraction quantization parameter is set in the compression processing circuit 105, thereby increasing the amount of code after compression and suppressing image quality deterioration. Note that the processes in steps S805, S807, and S809 count the number of times that the above three conditions (scene change, scene complexity, and compression state) are satisfied, and the count value exceeds a certain value (a certain number of times). This is to detect (repeat exceeding).
　以上のように、本第５の量子化パラメータ設定方法によれば、圧縮処理回路１０５から取得したビットレート、画像の複雑度、画像の動き量を用いて、ＧＯＰ単位で、次回圧縮時の量子化パラメータを算出することで、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生を回避できる。 As described above, according to the fifth quantization parameter setting method, using the bit rate, the complexity of the image, and the amount of motion of the image acquired from the compression processing circuit 105, the quantum for the next compression is calculated in GOP units. By calculating the conversion parameter, it is possible to avoid occurrence of code amount over even in a scene where code amount over has occurred in the past.
　このように、本発明にかかる画像処理装置及びカメラシステムは、コストを増やすことなく画像圧縮時の符号量オーバーを防ぐことができるという効果を有し、図９（ａ）に示されるスチルカメラや、図９（ｂ）に示されるビデオカメラ等として有用である。 As described above, the image processing apparatus and the camera system according to the present invention have an effect that it is possible to prevent the code amount from being excessive when the image is compressed without increasing the cost, and the still camera shown in FIG. This is useful as a video camera or the like shown in FIG.
　以上、本発明に係る画像処理装置及びカメラシステムについて、実施の形態に基づいて説明したが、本発明は、この実施の形態に限定されるものではない。本発明の趣旨を逸脱しない範囲で、本実施の形態に対して当業者が思いつく各種変形を施して得られる形態や、本実施の形態における第１～第５の量子化パラメータ設定方法における一部の手順を任意に組み合わせることで実現される量子化パラメータ設定方法も、本発明に含まれる。 As described above, the image processing apparatus and the camera system according to the present invention have been described based on the embodiment. However, the present invention is not limited to this embodiment. Without departing from the spirit of the present invention, a form obtained by subjecting the present embodiment to various modifications conceived by those skilled in the art, and a part of the first to fifth quantization parameter setting methods in the present embodiment A quantization parameter setting method realized by arbitrarily combining these procedures is also included in the present invention.
　たとえば、本実施の形態では、制御処理回路１０６は、圧縮状態判定、シーン変化判定、及び、シーン複雑度判定のすべてを判定したが、本発明は、それら３つの判定の少なくとも一つ（あるいは、任意の組み合わせ）でよい。少なくとも一つの判定であっても、圧縮処理回路１０５での直前の符号化における圧縮処理情報又は画像情報に依存して次回の符号化時の量子化パラメータが設定されるので、従来であれば符号量オーバーが発生していたシーンであっても符号量オーバーの発生が回避され得るからである。 For example, in the present embodiment, the control processing circuit 106 has determined all of the compression state determination, the scene change determination, and the scene complexity determination. However, the present invention is not limited to at least one of these three determinations (or Any combination). Even in the case of at least one determination, since the quantization parameter at the time of the next encoding is set depending on the compression processing information or the image information in the previous encoding in the compression processing circuit 105, in the conventional case, the code This is because the occurrence of the code amount over can be avoided even in a scene where the amount over has occurred.
　以上のように、本発明にかかる画像処理装置及びカメラシステムは、コストを増やすことなく画像圧縮時の符号量オーバーを防ぐことができるという効果を有し、スチルカメラやビデオカメラ等のカメラシステム等として有用である。 As described above, the image processing apparatus and the camera system according to the present invention have an effect that it is possible to prevent the code amount from being excessive when the image is compressed without increasing the cost, such as a camera system such as a still camera or a video camera. Useful as.
１０１・・・固体撮像素子
１０２・・・ＡＦＥ
１０３・・・画像処理回路
１０４・・・メモリ
１０５・・・圧縮処理回路
１０６・・・制御処理回路
１０７・・・ＬＣＤ　Ｉ／Ｆ
１０８・・・ＬＣＤ
１０９・・・カメラシステム
１１０・・・画像処理装置
１１１・・・シーン変化判定部
１１２・・・圧縮状態判定部
１１３・・・量子化パラメータ設定部
１１４・・・シーン複雑度判定部 101 ... Solid-state imaging device 102 ... AFE
103 ... Image processing circuit 104 ... Memory 105 ... Compression processing circuit 106 ... Control processing circuit 107 ... LCD I / F
108 ... LCD
DESCRIPTION OF SYMBOLS 109 ... Camera system 110 ... Image processing apparatus 111 ... Scene change determination part 112 ... Compression state determination part 113 ... Quantization parameter setting part 114 ... Scene complexity determination part

Claims (13)

  1. 　撮像素子から画像を取得し、取得した画像の輝度データ及び色差データを生成する画像処理回路と、
    　前記画像処理回路で生成された輝度データ及び色差データを入力画像として取得し、圧縮率を設定し、設定した圧縮率に従って、前記入力画像に対して、量子化を含む符号化をする圧縮処理回路と、
    　前記圧縮処理回路における直前の符号化で生成された、当該符号化に関する情報である圧縮処理情報及び符号化された画像に関する情報である画像情報の少なくとも一つを前記圧縮処理回路から取得し、取得した前記圧縮処理情報及び画像情報の少なくとも一つから、前記符号化における圧縮状態に関する判定である圧縮状態判定、前記入力画像においてシーン変化が生じたか否かに関する判定であるシーン変化判定、及び、前記入力画像の複雑度に関する判定であるシーン複雑度判定の少なくとも一つの判定を行い、その判定結果より、前記圧縮処理回路における次回の符号化時の量子化パラメータを設定する制御処理回路とを備えた画像処理装置。     An image processing circuit that acquires an image from the image sensor and generates luminance data and color difference data of the acquired image;
    A compression processing circuit that acquires luminance data and color difference data generated by the image processing circuit as an input image, sets a compression rate, and performs encoding including quantization on the input image according to the set compression rate When,
    Acquire and obtain from the compression processing circuit at least one of compression processing information, which is information related to the encoding, and image information, which is information related to the encoded image, generated by the previous encoding in the compression processing circuit. From at least one of the compression processing information and the image information, a compression state determination that is a determination regarding a compression state in the encoding, a scene change determination that is a determination regarding whether or not a scene change has occurred in the input image, and A control processing circuit that performs at least one determination of scene complexity determination, which is determination regarding the complexity of the input image, and sets a quantization parameter for the next encoding in the compression processing circuit based on the determination result Image processing device.
  2. 　請求項１記載の画像処理装置であって、
    　前記制御処理回路は、前記圧縮処理回路から取得する前記圧縮処理情報として、前記圧縮率を取得し、取得した前記圧縮率を予め定められた閾値と比較することで、前記圧縮状態判定を行う画像処理装置。     The image processing apparatus according to claim 1,
    The control processing circuit acquires the compression rate as the compression processing information acquired from the compression processing circuit, and compares the acquired compression rate with a predetermined threshold value to perform the compression state determination. Processing equipment.
  3. 　請求項１記載の画像処理装置であって、
    　前記制御処理回路は、前記圧縮処理回路から取得する前記圧縮処理情報として、前記圧縮処理回路での符号化における符号量を取得し、取得した前記符号量を予め定められた閾値と比較することで、前記圧縮状態判定を行う画像処理装置。     The image processing apparatus according to claim 1,
    The control processing circuit acquires a code amount in encoding in the compression processing circuit as the compression processing information acquired from the compression processing circuit, and compares the acquired code amount with a predetermined threshold value. An image processing apparatus that performs the compression state determination.
  4. 　請求項１記載の画像処理装置であって、
    　前記制御処理回路は、前記圧縮処理回路から取得する前記圧縮処理情報として、前記圧縮処理回路での符号化によって生成された符号のビットレートを取得し、取得した前記ビットレートを予め定められた閾値と比較することで、前記圧縮状態判定を行う画像処理装置。     The image processing apparatus according to claim 1,
    The control processing circuit acquires a bit rate of a code generated by encoding in the compression processing circuit as the compression processing information acquired from the compression processing circuit, and sets the acquired bit rate to a predetermined threshold value. An image processing apparatus that performs the compression state determination by comparing with.
  5. 　請求項１～４のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記圧縮処理回路から取得する前記画像情報として、画像の複雑度を取得し、取得した画像の複雑度を予め定められた閾値と比較することで、前記シーン複雑度判定を行う画像処理装置。     The image processing apparatus according to any one of claims 1 to 4,
    The control processing circuit acquires the complexity of the image as the image information acquired from the compression processing circuit, and compares the acquired complexity of the image with a predetermined threshold value, thereby determining the scene complexity. An image processing apparatus to perform.
  6. 　請求項１～４のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記圧縮処理回路から取得する前記画像情報として、画像の動き量を取得し、取得した画像の動き量を予め定められた閾値と比較することで、前記シーン変化判定を行う画像処理装置。     The image processing apparatus according to any one of claims 1 to 4,
    The control processing circuit performs the scene change determination by acquiring an image motion amount as the image information acquired from the compression processing circuit and comparing the acquired image motion amount with a predetermined threshold. Image processing device.
  7. 　請求項１記載の画像処理装置であって、
    　前記制御処理回路は、フレーム単位で次フレームの量子化パラメータを設定する画像処理装置。     The image processing apparatus according to claim 1,
    The control processing circuit is an image processing apparatus that sets a quantization parameter of a next frame in units of frames.
  8. 　請求項１記載の画像処理装置であって、
    　前記制御処理回路は、ＧＯＰ（Ｇｒｏｕｐ　ｏｆ　Ｐｉｃｔｕｒｅ）単位で次ＧＯＰの量子化パラメータを設定する画像処理装置。     The image processing apparatus according to claim 1,
    The control processing circuit is an image processing apparatus that sets a quantization parameter of the next GOP in GOP (Group of Picture) units.
  9. 　請求項１～８のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記シーン複雑度判定、前記シーン変化判定及び前記圧縮状態判定を行い、前記シーン複雑度判定でシーンが複雑と判定し、かつ、前記シーン変化判定でシーン変化有りと判定し、かつ、前記圧縮状態判定で低圧縮状態と判定したときに、前記量子化パラメータを一定値だけ加算することで量子化ステップを増加させる画像処理装置。     The image processing apparatus according to any one of claims 1 to 8,
    The control processing circuit performs the scene complexity determination, the scene change determination, and the compression state determination, determines that the scene is complex by the scene complexity determination, and determines that there is a scene change by the scene change determination. An image processing apparatus that increases a quantization step by adding a predetermined value to the quantization parameter when the compression state is determined to be a low compression state.
  10. 　請求項１～９のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記シーン複雑度判定、前記シーン変化判定及び前記圧縮状態判定を行い、前記シーン複雑度判定でシーンが単調と判定したとき、または、前記シーン変化判定でシーン変化無しと判定したとき、または、前記圧縮状態判定で高圧縮状態と判定したときに、前記量子化パラメータを一定値だけ減算することで量子化ステップを減少させる画像処理装置。     The image processing apparatus according to any one of claims 1 to 9,
    The control processing circuit performs the scene complexity determination, the scene change determination, and the compression state determination. When the scene is determined to be monotonous in the scene complexity determination, or determined that there is no scene change in the scene change determination. An image processing apparatus that reduces a quantization step by subtracting the quantization parameter by a certain value when the compression state is determined to be a high compression state.
  11. 　請求項１～８のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記シーン複雑度判定、前記シーン変化判定及び前記圧縮状態判定を行い、前記シーン複雑度判定でシーンが複雑と判定し、かつ、前記シーン変化判定でシーン変化有りと判定し、かつ、前記圧縮状態判定で低圧縮状態と判定した回数をカウントし、そのカウント値が一定値の閾値を超えたときに、前記量子化パラメータを一定値だけ加算することで量子化ステップを増加させる画像処理装置。     The image processing apparatus according to any one of claims 1 to 8,
    The control processing circuit performs the scene complexity determination, the scene change determination, and the compression state determination, determines that the scene is complex by the scene complexity determination, and determines that there is a scene change by the scene change determination. In addition, the number of times the compression state is determined to be a low compression state is counted, and when the count value exceeds a predetermined threshold value, the quantization parameter is increased by a predetermined value to increase the quantization step. Image processing apparatus
  12. 　請求項１～８、１１のいずれか１項に記載の画像処理装置であって、
    　前記制御処理回路は、前記シーン複雑度判定、前記シーン変化判定及び前記圧縮状態判定を行い、前記シーン複雑度判定でシーンが単調と判定した、または、前記シーン変化判定でシーン変化無しと判定した、または、前記圧縮状態判定で高圧縮状態が連続したと判定した回数をカウントし、そのカウント値が一定値の閾値を超えたときに、前記量子化パラメータを一定値だけ減算することで量子化ステップを減少させる画像処理装置。     The image processing apparatus according to any one of claims 1 to 8, wherein
    The control processing circuit performs the scene complexity determination, the scene change determination, and the compression state determination, and determines that the scene is monotonous in the scene complexity determination or determines that there is no scene change in the scene change determination. Alternatively, the number of times that the high compression state is determined to be continuous in the compression state determination is counted, and when the count value exceeds a certain threshold value, the quantization parameter is subtracted by a certain value to quantize An image processing apparatus that reduces steps.
  13. 　レンズを通して受けた光を電気信号に変換し撮像信号として出力する固体撮像素子と、
    　前記撮像信号をデジタル変換して、デジタル撮像信号を得るアナログ／デジタル変換回路と、
    　前記アナログ／デジタル変換回路から画像を入力し画像処理を行う請求項１～１２のいずれか１項に記載の画像処理装置とを具備するカメラシステム。     A solid-state imaging device that converts light received through the lens into an electrical signal and outputs it as an imaging signal;
    An analog / digital conversion circuit that digitally converts the imaging signal to obtain a digital imaging signal;
    A camera system comprising the image processing apparatus according to any one of claims 1 to 12, wherein an image is input from the analog / digital conversion circuit to perform image processing.
PCT/JP2010/004559 2009-08-21 2010-07-14 Image processing device and camera system WO2011021345A1 (en)

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