WO2016088393A1 - 画像処理装置及び方法、並びにプログラム及び記録媒体 - Google Patents
画像処理装置及び方法、並びにプログラム及び記録媒体 Download PDFInfo
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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
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
- H04N1/6002—Corrections within particular colour systems
- H04N1/6005—Corrections within particular colour systems with luminance or chrominance signals, e.g. LC1C2, HSL or YUV
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T1/00—General purpose image data processing
- G06T1/20—Processor architectures; Processor configuration, e.g. pipelining
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T5/00—Image enhancement or restoration
- G06T5/40—Image enhancement or restoration using histogram techniques
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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
- H04N1/46—Colour picture communication systems
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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
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
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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
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
- H04N1/6027—Correction or control of colour gradation or colour contrast
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- H—ELECTRICITY
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- H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
- H04N1/46—Colour picture communication systems
- H04N1/56—Processing of colour picture signals
- H04N1/60—Colour correction or control
- H04N1/6058—Reduction of colour to a range of reproducible colours, e.g. to ink- reproducible colour gamut
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- H—ELECTRICITY
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- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/67—Circuits for processing colour signals for matrixing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
- H04N9/00—Details of colour television systems
- H04N9/64—Circuits for processing colour signals
- H04N9/68—Circuits for processing colour signals for controlling the amplitude of colour signals, e.g. automatic chroma control circuits
Definitions
- the present invention relates to an image processing apparatus and method.
- the present invention also relates to a program for causing a computer to execute processing in the above-described image processing apparatus or method, and a computer-readable recording medium on which the program is recorded.
- a vivid image display may be preferred, and in order to respond to this, there is a method or apparatus aimed at improving natural saturation for an image including a low saturation portion. Proposed.
- Patent Literature 1 discloses a method for extracting the average saturation value of the input video from the color signal of the input video, determining a saturation improvement function based on the average saturation value, and improving the saturation. Yes.
- the conventional video display device has a narrow color reproduction range, and the above-described saturation improvement has been made in order to perform a more colorful display within a reproducible color gamut.
- the color reproduction range of video display devices has been widened, and thus the refinement of color gradation expression has become more important.
- the video consisting of the low saturation portion and the high saturation portion is not distinguished from the video consisting only of the middle saturation portion, and the saturation is appropriately improved. It may not be possible.
- saturation enhancement processing is often performed. For this reason, even in a video display device having a relatively narrow color reproduction range, in the case of an input video composed of a low saturation portion and a medium saturation portion, the above saturation enhancement processing is performed with a video display device with a relatively narrow color reproduction range. The difference with the case of doing is reduced. For example, when the input video includes a high saturation portion, if the saturation is improved, color collapse (originally different colors are made the same color and a subtle color difference becomes difficult for the viewer to recognize) occurs. In order to avoid this, when processing that does not improve the saturation in the high saturation part, it is not possible to obtain a higher color gradation expression, and it is possible to fully utilize the advantages of a video display device with a wide color reproduction range. Can not.
- the image processing apparatus includes: A color feature amount calculation unit that calculates saturation, hue, and brightness for each pixel from the input video signal; A saturation histogram generator for generating a saturation histogram from the saturation; A saturation conversion function generation unit that generates a saturation conversion function from the saturation histogram generated by the saturation histogram generation unit; A saturation conversion unit that converts the saturation of each pixel by the saturation conversion function generated by the saturation conversion function generation unit and outputs the converted saturation; Color component value calculation unit for calculating red, green, and blue color component values from the converted saturation output from the saturation conversion unit and the hue and brightness calculated by the color feature amount calculation unit It is characterized by providing.
- the image processing apparatus includes: A saturation calculation unit that calculates saturation for each pixel from the input video signal; A saturation histogram generator for generating a saturation histogram from the saturation; A saturation conversion multiplier determination function generation unit that generates a saturation conversion multiplier determination function from the saturation histogram generated by the saturation histogram generation unit; A saturation conversion multiplier determining unit that determines a saturation conversion multiplier for the pixel based on the saturation conversion multiplier determination function and the saturation of each pixel represented by the input video signal; And a multiplier that multiplies the saturation conversion multiplier for each pixel determined by the saturation conversion multiplier determination unit by the color difference of the same pixel represented by the input video signal.
- the saturation can be appropriately improved regardless of the saturation distribution of the input video, and at the same time, a high color gradation expression can be obtained.
- FIG. 1 is a block diagram showing a configuration of an image processing apparatus according to Embodiment 1 of the present invention. It is a block diagram which shows an example of the image display apparatus comprised by the image processing apparatus and display part of FIG. (A)-(d) is a figure which shows the example of saturation distribution. (A)-(d) is a figure which shows the example of the saturation conversion function by this invention. (A)-(d) is a figure which shows the example of the saturation conversion function by a prior art example. It is a block diagram which shows the structure of the image processing apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the example of saturation distribution, and a saturation conversion multiplier determination function.
- FIG. It is a block diagram which shows the structure of the image processing apparatus which concerns on Embodiment 3 of this invention. It is a block diagram which shows an image processing apparatus comprised with an example of the computer for implement
- FIG. 1 is a block diagram showing a configuration of an image processing apparatus 10 according to the first embodiment of the present invention.
- the illustrated image processing apparatus 10 includes input terminals 11r, 11g, and 11b, a color feature amount calculation unit 12, a saturation histogram generation unit 13, a saturation conversion function generation unit 14, a saturation conversion unit 15, and a saturation conversion unit 15.
- a degree signal delay unit 16 a hue signal delay unit 17, a brightness signal delay unit 18, a color component value calculation unit 19, and output terminals 20r, 20g, and 20b.
- FIG. 2 shows the image processing apparatus 10 shown in FIG.
- the display unit 40 can be configured by what is generally called a display. As shown in FIG. 2, the image processing apparatus 10 can be connected to the display unit 40, and color signals ROUT, GOUT, and BOUT output from the output terminals 20r, 20g, and 20b are supplied to the display unit 40 as described later.
- the display unit 40 displays an image based on the color signals ROUT, GOUT, and BOUT.
- the image processing apparatus 10 and the display unit 40 constitute a video display apparatus.
- the input terminals 11r, 11g, and 11b are supplied with standard video signals that can be supported by image display devices such as televisions and computers.
- the video signal is assumed to be composed of, for example, red, green, and blue color signals RIN, GIN, and BIN.
- the color feature amount calculation unit 12 calculates the saturation SAa, the hue HUa, and the lightness VAa from the color signals RIN, GIN, and BIN input to the input terminals 11r, 11g, and 11b.
- the color feature amount calculation unit 12 supplies a signal (saturation signal) representing the calculated saturation SAa to the saturation histogram generation unit 13 and also supplies it to the saturation conversion unit 15 via the saturation signal delay unit 16.
- the color feature amount calculation unit 12 calculates a color component value of a signal representing the calculated hue HUa (hue signal) and a signal representing the lightness VAa (lightness signal) via the hue signal delay unit 17 and the lightness signal delay unit 18, respectively. Supplied to the unit 19.
- the saturation signal representing the saturation SAa is indicated by the same sign SAa as the saturation
- the hue signal representing the hue HUa is indicated by the same sign HUa as the hue
- the lightness signal representing the brightness VAa is the lightness and It is indicated with the same reference VAa.
- the saturation histogram generation unit 13 generates a saturation histogram HSTa representing the distribution of the saturation SAa and supplies the saturation histogram HSTa to the saturation conversion function generation unit 14.
- the saturation conversion function generation unit 14 generates a saturation conversion function Fa from the saturation histogram HSTa input from the saturation histogram generation unit 13 and supplies the generated saturation conversion function Fa to the saturation conversion unit 15.
- the saturation conversion unit 15 converts the saturation SAa input from the color feature amount calculation unit 12 via the saturation signal delay unit 16 using the saturation conversion function Fa, and converts the converted saturation SAb to a color component. The value is output to the value calculation unit 19.
- the color component value calculation unit 19 is supplied from the saturation conversion unit 15 and is supplied from the color feature amount calculation unit 12 via the hue signal delay unit 17 and the lightness signal delay unit 18.
- the color component values ROUT, GOUT, and BOUT of red, green, and blue are calculated from the hue HUa and the lightness VAa, and the color signals ROUT, GOUT, and BOUT indicating the calculated color component values ROUT, GOUT, and BOUT are output to the output terminal 20r. , 20g, and 20b.
- the saturation signal delay unit 16 inputs the saturation signal SAa output from the color feature amount calculation unit 12 to the saturation conversion unit 15, and outputs the saturation from the saturation conversion function generation unit 14 to the saturation conversion unit 15. It is provided to synchronize with the input of the conversion function Fa.
- the hue signal delay unit 17 and the lightness signal delay unit 18 input the hue signal HUa and the lightness signal VAa output from the color feature amount calculation unit 12 to the color component value calculation unit 19 and the color component value calculation unit 19 from the color conversion unit 15. This is provided to synchronize with the input of the saturation signal SAb to the value calculation unit 19.
- the red, green, and blue color signals ROUT, GOUT, and BOUT output from the color component value calculation unit 19 via the output terminals 20r, 20g, and 20b are supplied to the display unit 40.
- the display unit 40 displays an image based on the red, green, and blue color signals ROUT, GOUT, and BOUT.
- the color signals RIN, GIN, and BIN input to the input terminals 11r, 11g, and 11b represent the red, green, and blue color component values of each pixel.
- the color feature amount calculation unit 12 calculates the saturation SAa, the hue HUa, and the lightness VAa from the color component values RIN, GIN, and BIN represented by the color signals input to the input terminals 11r, 11g, and 11b. This calculation is performed by a commonly performed calculation.
- the saturation histogram generation unit 13 receives the saturation signal SAa from the color feature amount calculation unit 12 and generates a saturation histogram HSTa representing the distribution of the saturation SAa.
- the appearance frequency Da for each class CLa of gradation values representing the saturation SAa is counted over a certain period or range, for example, one frame.
- the appearance frequency of the gradation value means the appearance frequency of the pixel having the gradation value.
- the appearance frequency Da of the gradation value in the class CLa is represented by “Da (CLa)”. The same applies to other values.
- the frequency of appearance of gradation values in the class CLa may be simply referred to as the frequency of the class CLa.
- Each class CLa is composed of one gradation value or a plurality of consecutive gradation values, and does not overlap each other.
- each class is specified by the gradation value of the saturation SAa belonging to the class.
- the appearance frequency of saturation over a plurality of frames may be obtained, and the appearance frequency per frame may be obtained by dividing by the number of frames.
- the saturation conversion function generation unit 14 generates a saturation conversion function Fa from the saturation histogram HSTa input from the saturation histogram generation unit 13 and supplies it to the saturation conversion unit 15.
- the saturation conversion function Fa uses a given saturation (input saturation) SAa as a variable, and gives the value of the converted saturation (output saturation) SAb by the value of the function Fa corresponding to the variable, that is, Represents the relationship between the input saturation SAa and the output saturation SAb.
- the frequency Da (CLa) of each class CLa of the saturation histogram HSTa is cumulatively added in order from the lower class CLa (the lower gradation value belonging to the class), and the cumulative added value up to each class is
- the saturation conversion function Fa is generated by setting a representative value of the class, for example, a function value corresponding to the maximum value of the gradation values belonging to the class.
- the gradation value belonging to each class is the representative value of the class.
- At least one of the maximum value and the minimum value with respect to the slope of the saturation conversion function Fa (the ratio of the increase in the corresponding output saturation SAb to the increase in the input saturation SAa). May be determined in advance. For example, the adjustment may be performed so that the inclination is not more than a predetermined maximum value and not less than a predetermined minimum value.
- the upper limit value and the lower limit value corresponding to the maximum value and the minimum value of the gradient are previously set for the frequency Da (CLa) of each class CLa of the saturation histogram HSTa used for generation of the saturation conversion function Fa. It is determined by redistributing the amount exceeding the upper limit and the amount lower than the lower limit.
- the upper limit value corresponds to the product of the maximum value of the slope, the reciprocal of the number of classes, and the number of pixels used to generate the histogram
- the lower limit value is the minimum value of the slope and the histogram. This corresponds to the product of the number of pixels used for generation.
- the frequency Da (CLa) of each class (attention class) CLa exceeds the above upper limit value
- the excess is transferred to one or more other classes, whereby the attention class
- the frequency of CLa is decreased to coincide with the above upper limit value, and the frequency of other classes is increased.
- the portion exceeding the upper limit is divided, and each divided portion is assigned to another class.
- the frequency of the class is increased by the allocated amount.
- the frequency of the attention class CLa is reduced by the total of the assignments of the other classes.
- the frequency Da (CLa) of each class (attention class) CLa is less than the above lower limit value (when it falls below the lower limit value)
- the amount that is insufficient is 1 or 2 or more. It is inherited from another class, thereby increasing the frequency of the class of interest to coincide with the above lower limit and decreasing the frequency of the other class.
- the missing part is divided, and each divided part is assigned to another class.
- the frequency of the class is reduced by the assigned part. Increase the frequency by the allocated amount.
- the attention class CLa increases the frequency by the sum of the other classes allocated. It can be said that such transfer is a process of transferring a negative value corresponding to the shortage to another class.
- the maximum value and the minimum value of the slope of the saturation conversion function Fa can be determined separately for each saturation region.
- the maximum value may be set to a relatively small value, for example, 1 in the low saturation range (a range where the saturation is equal to or less than a predetermined value).
- the saturation histogram HSTa representing the saturation distribution is as shown in FIGS. 3A to 3D
- the horizontal axis represents the input saturation SAa, and hence the class CLa corresponding to each gradation value of the input saturation SAa
- the vertical axis represents the class CLa composed of the input saturation SAa.
- the appearance frequency Da of the gradation value to which it belongs is shown.
- the input saturation SAa is represented by a value normalized by the maximum value. That is, the maximum value of the range of possible values for the input saturation SAa is 1. 3 (a) and 3 (b), the average value SAam of the saturation SAa is 0.5, but the shape of the saturation distribution is different. In FIG. 3 (a), the input saturation SAa is medium. In FIG. 3B, the input saturation SAa does not exist so much in the middle saturation region and is distributed in a low saturation region and a high saturation region. Further, in FIG. 3C, a large amount of input saturation SAa is distributed in the low saturation region, and in FIG. 3D, a large amount of input saturation SAa is distributed in the high saturation region.
- 4 (a) to 4 (d) show the saturation conversion functions Fa corresponding to the saturation distributions shown in FIGS. 3 (a) to 3 (d), respectively.
- the horizontal axis represents the input saturation SAa
- the vertical axis represents the output saturation SAb corresponding to the input saturation SAa, that is, the value of the saturation conversion function Fa corresponding to the input saturation SAa.
- Fa (SAa) is shown.
- 4A to 4D similarly to FIGS. 3A to 3D, the maximum value of the range of values that can be taken by the input saturation SAa is set to 1, and the output saturation SAb can be taken. The maximum value range is also 1.
- Each of the saturation conversion functions Fa in FIGS. 4A to 4D is generated so that the inclination thereof falls within a predetermined range from the minimum value to the maximum value.
- the adjustment for keeping the inclination within the predetermined range is performed by the redistribution of the frequency of each class. This redistribution is performed so that the curve representing the saturation conversion function Fa passes through (0, 0) and (1.0, 1.0) and is continuous as described above.
- the specific method of frequency redistribution may be the same as the method of frequency redistribution at the time of generating the saturation conversion multiplier determining function, which will be described later with reference to the second embodiment.
- the generation of the saturation conversion function Fa in the saturation conversion function generation unit 14 is performed for each frame.
- the saturation histogram generation unit 13 When the saturation histogram generation unit 13 generates the saturation histogram HSTa based on the saturation SAa of the pixels in each frame, the saturation conversion function for the frame based on the saturation SAa of the pixels in the same frame. Fa is generated.
- the saturation histogram generation unit 13 When the saturation histogram generation unit 13 generates the saturation histogram HSTa based on the saturation SAa of the pixels in the plurality of frames, the saturation of the frame based on the saturation SAa of the pixels of the plurality of frames.
- the degree conversion function Fa is generated.
- the code Fa (f) may be used to emphasize the saturation conversion function Fa for each frame Fr (f).
- the saturation signal delay unit 16 is the time required for the saturation histogram generation unit 13 and the saturation conversion function generation unit 14 to perform the above processing and output the saturation conversion function Fa (the saturation of the saturation signal SAa).
- the saturation signal SAa is delayed and output to the saturation conversion unit 15 by the time from the input to the histogram generation unit 13 to the output of the saturation conversion function Fa by the saturation conversion function generation unit 14,
- the saturation conversion function Fa (f) is input for the certain frame Fr (f) from the saturation conversion function generation unit 14 to the saturation conversion unit 15, the saturation of each pixel of the same frame Fr (f)
- the signal SAa (f, x) is supplied to the saturation conversion unit 15.
- SAa (f, x) is used to emphasize that it is a saturation signal of each pixel Px (x) of the frame Fr (f). In the case where such enhancement is not necessary, or in the description common to the saturation signals of a plurality of pixels, the symbol SAa is simply used. If there is no need to emphasize which frame's pixel saturation signal, the code SAa (x) may be used. The same applies to other codes.
- the saturation conversion unit 15 converts the saturation SAa (f, x) of each pixel (target pixel) input from the color feature amount calculation unit 12 using the saturation conversion function Fa (f),
- the saturation SAb (f, x) is output to the color component value calculation unit 19.
- the value of the function Fa (f) corresponding to the saturation SAa (f, x), that is, the output saturation SAb (f, x) is output.
- the saturation conversion in the saturation conversion unit 15 is a process for each pixel.
- the saturation conversion unit 15 converts the saturation SAa (f, x) of each pixel of each frame Fr (f) and obtains the converted saturation SAb (f, x), the same frame Fr ( The saturation conversion function Fa (f) defined for f) is used.
- the saturation histogram generation unit 13 and the saturation conversion function generation unit 14 perform the above processing to output the saturation conversion function Fa (f).
- the time required for the degree conversion unit 15 to perform the above processing and output the converted saturation signal SAb (from the input of the saturation signal SAa to the saturation histogram generation unit 13 to the conversion by the saturation conversion unit 15)
- the hue signal HUa and the lightness signal VAa are delayed by the time until the output of the subsequent saturation signal SAb), whereby the saturation conversion unit 15 sends the color component value calculation unit 19 to a pixel in a certain frame Fr (f).
- the saturation signal SAb (f, x) for Px (f, x) is supplied, the hue signal HUa (f, x) and the lightness signal VAa (f, x) of the same pixel in the same frame are colored. Supplied to the component value calculator 19 To be.
- the color component value calculation unit 19 calculates the red, green, and blue color component values ROUT from the saturation signal SAb output from the saturation conversion unit 15 and the hue HUa and lightness VAa output from the color feature amount calculation unit 12.
- GOUT, BOUT representing color signals ROUT, GOUT, BOUT are output. This process is also performed for each pixel. That is, from the saturation signal SAb (x) for each pixel (target pixel), the hue signal HUa (x) and the lightness signal VAa (x) for the same pixel, red, green, and blue color signals for the same pixel.
- ROUT (x), GOUT (x), and BOUT (x) are output.
- the calculation of the color component values ROUT, GOUT, and BOUT is performed by a generally performed method.
- FIGS. 5A to 5D show the saturation conversion function Fc according to the conventional example.
- FIGS. 5A to 5D show saturation conversion functions Fc corresponding to the saturation distributions shown in FIGS. 3A to 3D, respectively. Since the average saturation is the same in FIGS. 3 (a) and 3 (b), the saturation conversion function Fc according to the conventional example is the same as shown in FIGS. 5 (a) and 5 (b).
- the saturation conversion function Fc according to the conventional example is the same as shown in FIGS. 5 (a) and 5 (b).
- both the conventional example and the present embodiment are as shown in FIGS. 5C and 4C.
- the improvement in saturation can be expected in almost the same way.
- FIG. 3D when the input saturation SAa is widely distributed in the high saturation region, in the conventional example, as shown in FIG.
- the slope of the saturation conversion function Fa in the high saturation region can be further increased, and the high saturation can be achieved. And the color gradation expression can be obtained.
- the maximum value and the minimum value of the gradient of the saturation conversion function Fa for each saturation region, different conversion characteristics can be provided for each saturation region. For example, by setting the maximum value of the slope of the saturation conversion function Fa in the low saturation region to be small (such as 1), the high saturation in the low saturation region is suppressed, and the color noise and the like are suppressed from being noticeable. be able to. Also, by setting a large maximum value in the intermediate saturation area where there are many colors intended to be reproduced, it is possible to emphasize the color difference in the intermediate saturation area. Furthermore, by providing the minimum value, it is possible to prevent the difference in saturation from being compressed and the difference in color from becoming too small. On the other hand, by setting the maximum value, it is possible to avoid sudden conversion of the function value.
- the saturation can be controlled in accordance with the characteristics of the display device used. Will improve. For example, a display device with a narrow color reproduction range cannot display dark colors (highly saturated colors), but displays intermediate colors that are often included in general content in dark (with higher saturation).
- a saturation conversion function (a curve represented by the function) is changed according to the input video, and at the same time, at least one of the maximum value and the minimum value of the slope of the function is controlled. By doing so, the saturation conversion function can be adapted to the characteristics of the display device.
- each class of the saturation histogram HSTa is composed of a single gradation value, but each class may be composed of a plurality of gradation values.
- FIG. FIG. 6 is a block diagram showing a configuration of the image processing apparatus 10b according to the second embodiment of the present invention.
- the illustrated image processing apparatus 10b includes input terminals 21y, 21cb and 21cr, a saturation calculation unit 22, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, and a saturation conversion multiplier determination unit 24.
- a saturation signal delay unit 25 color difference signal delay units 28 and 29, a luminance signal delay unit 30, multipliers 26 and 27, and output terminals 31y, 31cb, and 31cr.
- Video signals of a standard that can be supported by an image display device such as a television or a computer are input to the input terminals 21y, 21cb, and 21cr.
- the video signal is composed of, for example, a luminance signal YIN, a color difference (blue) signal CbIN, and a color difference (red) signal CrIN.
- the video signal composed of the luminance signal YIN and the color difference signals CbIN and CrIN is input, and the luminance signal YOUT and the color difference signals CbOUT and CrOUT are output. Accordingly, as the display unit 40, a display that receives the luminance signal YOUT and the color difference signals CbOUT and CrOUT is used.
- the saturation calculation unit 22 calculates a saturation SAc from the luminance signal YIN and the color difference signals CbIN, CrIN input to the input terminals 21y, 21cb, 21cr, and generates a saturation histogram of the saturation signal SAc representing the saturation SAc.
- the signal is supplied to the unit 13 b and output to the saturation conversion multiplier determination unit 24 via the saturation signal delay unit 25.
- the saturation histogram generation unit 13b generates a saturation histogram HSTb representing the distribution of the saturation SAc, and outputs the saturation histogram HSTb to the saturation conversion multiplier determination function generation unit 23.
- the saturation conversion multiplier determination function generation unit 23 generates a saturation conversion multiplier determination function Fb from the saturation histogram HSTb input from the saturation histogram generation unit 13b, and outputs it to the saturation conversion multiplier determination unit 24.
- the saturation conversion multiplier determination unit 24 receives the saturation signal SAc input from the saturation calculation unit 22 via the saturation signal delay unit 25 and the saturation conversion multiplier input from the saturation conversion multiplier determination function generation unit 23.
- the saturation conversion multiplier Kb is determined from the determination function Fb and output to the multipliers 26 and 27.
- the multipliers 26 and 27 respectively receive the color difference signals CbIN and CrIN supplied from the input terminals 21cb and 21cr via the color difference signal delay units 28 and 29, and the saturation conversion multiplier Kb input from the saturation conversion multiplier determination unit 24. And the multiplication result is output to the output terminals 31cb and 31cr as output color difference signals CbOUT and CrOUT.
- the luminance signal YIN input to the input terminal 11y is delayed by the luminance signal delay unit 30, and then output from the output terminal 31y as the output luminance signal YOUT.
- the saturation signal delay unit 25 receives the input of the saturation signal SAc output from the saturation calculation unit 22 to the saturation conversion multiplier determination unit 24 from the saturation conversion multiplier determination function generation unit 23 to the saturation conversion multiplier determination unit. This is provided to synchronize with the input of the saturation conversion multiplier determination function Fb to 24.
- the color difference signal delay units 28 and 29 input the color difference signal CbIN and the signal CrIN input to the input terminals 21cb and 21cr to the multipliers 26 and 27, respectively, and the chroma conversion multiplier determination unit 24 to the multipliers 26 and 27. Is provided to synchronize with the input of the saturation conversion multiplier Kb.
- the luminance signal delay unit 30 synchronizes the output of the luminance signal YIN input to the input terminal 21y to the output terminal 31y from the multipliers 26 and 27 to the output terminals 31cb and 31cr with the output of the output color difference signals CbOUT and CrOUT. It is provided for this purpose.
- the luminance signal YIN input to the input terminal 21y represents the luminance value of each pixel.
- the color difference signals CbIN and CrIN input to the input terminals 21cb and 21cr represent the color difference component values of each pixel.
- the saturation calculation unit 22 calculates the saturation SAc from the luminance signal YIN and the color difference signals CbIN, CrIN input to the input terminals 21y, 21cb, 21cr. This calculation is performed by a commonly performed calculation.
- the saturation histogram generation unit 13b generates a saturation histogram HSTb representing the distribution of the saturation SAc.
- the appearance frequency Db of the gradation value representing the saturation SAc for each class CLb is counted over a certain range, for example, one frame.
- the frequency Db of the class CLb is represented by “Db (CLb)”.
- Each class CLb is composed of one gradation value or a plurality of consecutive gradation values, and does not overlap each other.
- the gradation value is represented by 10 bits and takes values from 0 to 1023, and is divided into 16 classes. Therefore, a case where each class is composed of 64 gradation values will be described.
- the appearance frequency of saturation over a plurality of frames may be obtained, and the appearance frequency per frame may be obtained by dividing by the number of frames.
- the saturation conversion multiplier determination function generation unit 23 generates a saturation conversion multiplier determination function Fb from the saturation histogram HSTb input from the saturation histogram generation unit 13 b and supplies the generated saturation conversion multiplier determination function Fb to the saturation conversion multiplier determination unit 24.
- the saturation conversion multiplier determination function Fb has a saturation (input saturation) SAc as a variable, and a saturation conversion multiplier based on the ratio Ks of the value SAd of the function Fb corresponding to the input saturation SAc to the input saturation SAc. It represents Kb.
- the frequency Dc (CLb) of each class CLb of the saturation histogram HSTb is cumulatively added in order from the lower class CLb (the lowest gradation value belonging to the class), and the cumulative addition value up to each class is
- the saturation conversion multiplier determination function Fb is generated by setting a representative value of the class, for example, a function value corresponding to the maximum value of the gradation values belonging to the class.
- the maximum value and the slope of the saturation conversion multiplier determination function Fb (the ratio of the increase in the value SAd of the corresponding function Fb to the increase in the input saturation SAc) At least one of the minimum values may be determined in advance. For example, the adjustment may be performed so that the inclination is not more than a predetermined maximum value and not less than a predetermined minimum value.
- This adjustment is performed, for example, with respect to the frequency Db (CLb) of each class CLb of the saturation histogram HSTb used for generation of the saturation conversion multiplier determination function Fb, the upper limit value and the lower limit value corresponding to the maximum value and the minimum value of the above-described gradient. Is determined in advance, and the portion exceeding the upper limit and the portion lower than the lower limit are redistributed.
- the upper limit value corresponds to the product of the maximum value of the slope and the number of pixels used for generating the histogram
- the lower limit value is the minimum value of the slope and the pixel value used for generating the histogram. Corresponds to product with number.
- the frequency Dc (CLb) of each class (attention class) CLb exceeds the above upper limit value
- the excess is transferred to one or more other classes, whereby the attention class
- the frequency of CLb is decreased to coincide with the above upper limit value, and the frequency of other classes is increased.
- the portion exceeding the upper limit is divided, and each divided portion is assigned to another class.
- the frequency of the class is increased by the allocated amount.
- the attention class CLb the frequency is decreased by the allocated amount.
- the target class CLb is reduced in frequency by the sum of the other classes assigned.
- the missing amount is 1 or 2 or more. It is inherited from another class, thereby increasing the frequency of the class of interest to coincide with the above lower limit and decreasing the frequency of the other class.
- the missing part is divided, and each divided part is assigned to another class.
- the frequency of the class is reduced by the assigned part. Increase the frequency by the allocated amount.
- the target class CLb increases the frequency by the sum of the other classes assigned. It can be said that such transfer is a process of transferring a negative value corresponding to the shortage to another class.
- the maximum value and minimum value of the slope of the saturation conversion multiplier determination function Fb can be determined separately for each saturation region.
- the maximum value may be set to a relatively low value, for example, 1 in the low saturation range (a range where the saturation is equal to or less than a predetermined value).
- FIG. 7 shows the saturation distribution and the saturation conversion multiplier determination function Fb superimposed on each other.
- the bar graph of FIG. 7 represents the appearance frequency Db for each class of the saturation histogram HSTb, and the broken line represents the value SAd of the saturation conversion multiplier determination function Fb.
- the saturation conversion multiplier determination function Fb is generated so that the slope of the saturation conversion multiplier determination function Fb is increased.
- the saturation conversion multiplier determination function Fb is obtained in the same manner as the saturation conversion function Fa of the first embodiment. However, in the saturation conversion function Fa, the relationship between the input saturation SAa and the value (output saturation) SAb of the function Fa corresponding to the input saturation SAa is used for determining the output saturation SAb. Thus, the saturation conversion multiplier determination function Fb has a relationship between the input saturation SAc and the ratio Ks of the value (output saturation) of the function Fb corresponding to the input saturation SAc to the input saturation SAc. Used to determine Kb. Specifically, the ratio Ks corresponding to the input saturation SAc is used as the saturation conversion multiplier Kb for the input saturation SAc.
- FIG. 8 is a diagram for explaining processing for setting the maximum value to the slope of the saturation conversion multiplier determination function Fb.
- the upper limit value UL corresponding to the maximum value of the inclination is set in the frequency of each class CLb to exceed the upper limit value UL. In some cases, hand over the frequency to another class. For example, when the saturation distribution is as shown in FIG. 7 and the upper limit value UL is set as shown in FIG.
- the frequency of the class with the gradation value of saturation SAc from 640 to 704 is the upper limit. Exceeds value. In that case, the frequency of the class whose chroma gradation value is from 640 to 704 is changed to the upper limit value UL, and the frequency exceeding the upper limit value UL is transferred to another class. For example, it is divided into other 15 classes and handed over. That is, distribute. In this distribution, all classes may be assigned equally, or more may be assigned to closer classes.
- a saturation conversion multiplier determination function Fb is generated based on the new saturation distribution (adjusted histogram) thus created.
- the saturation conversion multiplier determination function generation unit 23 generates the saturation conversion multiplier determination function Fb for each frame.
- the saturation histogram generation unit 13b When the saturation histogram generation unit 13b generates the saturation histogram HSTb based on the saturation SAc of the pixels in each frame, the saturation conversion multiplier for the frame based on the saturation SAc of the pixels in the same frame.
- the determination function Fb is generated.
- the saturation histogram generation unit 13b generates the saturation histogram HSTb based on the saturation SAc of the pixels in the plurality of frames, the saturation of the frame based on the saturation SAc of the pixels of the plurality of frames.
- the degree conversion multiplier determination function Fb is generated.
- the code Fb (f) may be used to emphasize the saturation conversion multiplier determination function Fb for each frame Fr (f).
- the saturation signal delay unit 25 is the time required for the saturation histogram generation unit 13b and the saturation conversion multiplier determination function generation unit 23 to perform the above processing and output the saturation conversion multiplier determination function Fb (saturation signal).
- the saturation conversion multiplier is obtained by delaying the saturation signal SAc by the time from the input of the SAc to the saturation histogram generation unit 13b until the output of the saturation conversion multiplier determination function Fb by the saturation conversion multiplier determination function generation unit 23).
- the saturation conversion multiplier determination function Fb (f) for a certain frame Fr (f) is input from the saturation conversion multiplier determination function generation unit 23 to the saturation conversion multiplier determination unit 24.
- the saturation signal SAc (f, x) of each pixel in the same frame is supplied to the saturation conversion multiplier determining unit 24.
- the saturation conversion multiplier determination unit 24 refers to the saturation conversion multiplier determination function Fb generated by the method as described above, and the saturation conversion multiplier corresponding to the saturation signal SAc input from the saturation calculation unit 22. Kb is determined.
- the determination of the saturation conversion multiplier Kb is a process for each pixel. That is, the corresponding saturation conversion multiplier Kb (f, x) is determined for the saturation SAc (f, x) of each pixel (target pixel) of each frame.
- the saturation defined for the same frame Fr (f) A conversion multiplier determination function Fb (f) is used.
- FIG. 9 is a diagram for explaining the saturation conversion multiplier determining unit 24.
- the broken line shown in FIG. 9 indicates the saturation conversion multiplier determination function Fb.
- the broken point of the broken line represents a function value in which the position in the horizontal axis direction represents a representative value of each class, and the position in the vertical axis direction corresponds to the representative value.
- the conversion multiplier Kb Represents the conversion multiplier Kb.
- the output for the input saturation SAc is output.
- the ratio Ks (x) corresponding to the input saturation SAc (x) is obtained by interpolation from the ratios Ksa and Ksb corresponding to the input saturations SAca and SAcb, and the obtained ratio Ks (x) is determined as the target pixel Px ( A saturation conversion multiplier Kb (x) for x).
- the interpolation of the ratio Ks (x) can be expressed by the following equation (1).
- Ks (x) (Ksa ⁇ Db + Ksb ⁇ Da) / (Da + Db) (1)
- the output saturation SAd (x) corresponding to the input saturation SAc (x) for the target pixel Px (x) is obtained by interpolation, and the obtained output is obtained.
- the ratio of the pixel of interest Px (x) that is, the saturation conversion multiplier Kb (x) may be obtained. Is equivalent to determining the ratio Ks (x) by interpolation.
- the input saturation SAc (x) of the target pixel does not match any of the saturation SAci corresponding to the 16 break points
- the input saturation SAc (x) is located on both sides.
- An output saturation SAd (x) corresponding to the input saturation SAc (x) is obtained by interpolation from the values of the functions corresponding to the input saturation SAca, SAcb corresponding to the break point, that is, the output saturation SAda, SAdb.
- a ratio Ks (x) of the output saturation SAd (x) to the input saturation SAc (x) is set as a saturation conversion multiplier Kb (x) for the target pixel.
- the interpolation of the output saturation SAd (x) can be expressed by the following equation (2).
- SAd (x) (SAd (a) ⁇ Db + SAd (b) ⁇ Da) / (Da + Db) (2)
- Kb (x) SAd (x) / SAc (x) (3)
- the chrominance signal delay units 28 and 29 respectively convert the chrominance signals CbIN and CrIN input from the input terminals 21cb and 21cr into a saturation calculation unit 22, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, and Delayed by the time required for processing in the saturation conversion multiplier determining unit 24 (time from the input of the color difference signals CbIN and CrIN to the input terminals 21cb and 21cr to the output of the saturation conversion multiplier Kb) and output to the multipliers 26 and 27
- the saturation conversion multiplier Kb (f, x) for the pixel Px (x) of the frame Fr (f) in the multipliers 26 and 27 is supplied from the saturation conversion multiplier determination unit 24.
- color difference signals CbIN (f, x) and CrIN (f, x) of the same pixel in the same frame are supplied to the multipliers 26 and 27.
- the multipliers 26 and 27 respectively add the saturation conversion multiplier determining unit 24 to the color difference signals CbIN (f, x) and CrIN (f, x) of each pixel (target pixel) output from the color difference signal delay units 28 and 29, respectively. Is multiplied by the saturation conversion multiplier Kb (f, x) for the same pixel in the same frame, and the multiplication result is output as the output color difference signals CbOUT (f, x) and CrOUT (f, x) for the same pixel. Output as.
- the luminance signal delay unit 30 converts the luminance signal YIN input from the input terminal 21y into a saturation calculation unit 22, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, a saturation conversion multiplier determination unit 24, And the time required for processing in the multipliers 26 and 27 (the time from the input of the luminance signal YIN and the color difference signals CbIN and CrIN to the input terminals 21y, 21cb and 21cr to the output of the output color difference signals CbOUT and CrOUT).
- the color difference signals CbOUT (f, x) and CrOUT (f) for the pixel Px (x) of a certain frame Fr (f) are output from the multipliers 26 and 27 to the output terminals 31cb and 31cr.
- X) is supplied, the luminance signal YIN (f, x) of the same pixel in the same frame is supplied to the output terminal 31y.
- a saturation conversion multiplier determination function Fb is generated, a saturation conversion multiplier is determined from the saturation conversion multiplier determination function Fb, and the color difference signal is multiplied by the determined saturation conversion multiplier.
- the color difference signal is multiplied by the determined saturation conversion multiplier.
- the method for generating the saturation conversion multiplier determination function Fb, the value referring to the saturation conversion multiplier determination function Fb, and the value by which the determined saturation conversion multiplier is multiplied can be selected independently, versatility is high.
- the “value to be multiplied by the determined saturation conversion multiplier” is CbIN and CrIN in the example of FIG.
- the “value referring to the saturation conversion multiplier determination function Fb” is the saturation SAc. The fact that they can be selected independently means that the same processing can be applied even if a value other than the above is selected.
- the maximum value and the minimum value of the slope of the saturation conversion multiplier determination function Fb for each saturation region, different conversion characteristics can be provided for each saturation region. For example, by setting the maximum value of the slope of the saturation conversion multiplier determination function Fb in the low saturation region to a small value (such as 1), the high saturation in the low saturation region is suppressed, and color noise and the like are not conspicuous. can do. Also, by setting a large maximum value in the intermediate saturation area where there are many colors intended to be reproduced, it is possible to emphasize the color difference in the intermediate saturation area. Furthermore, by providing the minimum value, it is possible to prevent the difference in saturation from being compressed and the difference in color from becoming too small. On the other hand, by setting the maximum value, it is possible to avoid sudden conversion of the function value.
- a small value such as 1
- the saturation can be controlled in accordance with the characteristics of the display device to be used, and the image quality is improved.
- a display device with a narrow color reproduction range cannot display dark colors (highly saturated colors), but displays intermediate colors that are often included in general content in dark (with higher saturation).
- the minimum value of the intermediate saturation region to a large value and setting the maximum value of the high saturation region to a small value, as shown in FIG. 7, a curve that protrudes upward from the intermediate saturation region to the high saturation region Is more likely to be generated.
- the present invention is characterized in that a saturation conversion multiplier determining function (a curve represented by the function) is changed in accordance with the input video, and at least one of the maximum value and the minimum value of the slope of the function is also included.
- the saturation conversion multiplier determining function can be adapted to the characteristics of the display device.
- each class of the histogram HSTb is composed of 64 gradation values, but the number of gradation values belonging to each gradation may be other than 64.
- each class of the histogram HSTb may be composed of only one gradation value. In that case, the process of interpolating the ratio of the output saturation to the input saturation described with reference to FIG. 9 becomes unnecessary.
- the color component values ROUT, GOUT, and BOUT are calculated using the converted saturation SAb generated by performing the saturation conversion by the saturation conversion unit 15.
- the chroma conversion multiplier Kb is used to convert the color difference signals CbIN and CrIN, thereby realizing saturation conversion. That is, saturation conversion is realized without converting a signal representing the saturation SAc.
- the processing is relatively simple, The scale of the circuit can be reduced.
- FIG. 10 is a block diagram showing a configuration of an image processing apparatus 10c according to Embodiment 3 of the present invention.
- the illustrated image processing apparatus 10c includes input terminals 11r, 11g, and 11b, a saturation calculation unit 22, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, and a saturation conversion multiplier determination unit 24.
- Multipliers 26 and 27, color feature amount calculation unit 31, saturation signal delay unit 25, color difference signal delay units 28 and 29, luminance signal delay unit 30, color component value calculation unit 32, and output Terminals 20r, 20g, and 20b are provided.
- Video signals of a standard that can be supported by an image display device such as a television or a computer are input to the input terminals 11r, 11g, and 11b.
- the video signals are, for example, red, green, and blue signals RIN, GIN, and BIN.
- the image processing apparatus 10c in FIG. 10 can be used in place of the image processing apparatus 10 in FIG.
- a video signal composed of the color signals RIN, GIN, and BIN is input, and the color signals ROUT, GOUT, and BOUT are output.
- the display unit 40 a display unit that receives the color signals ROUT, GOUT, and BOUT is used as in the case of using the image processing apparatus 10.
- the saturation calculation unit 22 calculates the saturation SAe from the red, green, and blue signals RIN, GIN, and BIN input to the input terminals 11r, 11g, and 11b, and the saturation signal SAe that represents the saturation SAe.
- the data is output to the histogram generation unit 13b and the saturation conversion multiplier determination unit 24.
- the saturation histogram generation unit 13b generates a saturation histogram HSTb representing the distribution of saturation and outputs it to the saturation conversion multiplier determination function generation unit 23.
- the saturation conversion multiplier determination function generation unit 23 generates a saturation conversion multiplier determination function Fb from the saturation histogram HSTb and outputs it to the saturation conversion multiplier determination unit 24.
- the saturation conversion multiplier determination unit 24 receives the saturation signal SAe input from the saturation calculation unit 22 via the saturation signal delay unit 25 and the saturation conversion multiplier input from the saturation conversion multiplier determination function generation unit 23.
- the saturation conversion multiplier Kb is determined from the determination function Fb and output to the multipliers 26 and 27.
- the color feature amount calculation unit 31 calculates the luminance signal Y and the color difference signals Cb and Cr from the red, green, and blue signals RIN, GIN, and BIN input to the input terminals 11r, 11g, and 11b.
- the color difference signal Cb and Cr are supplied to the multipliers 26 and 27 via the color difference signal delay units 28c and 29c.
- the multipliers 26 and 27 include the color difference signals Cb and Cr supplied from the color feature amount calculation unit 31 via the color difference signal delay units 28c and 29c, and the saturation conversion multiplier Kb input from the saturation conversion multiplier determination unit 24. And the multiplication result is output to the color component value calculation unit 32 as enhanced color difference signals CbM and CrM.
- the saturation signal delay unit 25 receives the input of the saturation signal SAe output from the saturation calculation unit 22c to the saturation conversion multiplier determination unit 24 from the saturation conversion multiplier determination function generation unit 23 to the saturation conversion multiplier determination unit. This is provided to synchronize with the input of the saturation conversion multiplier determination function Fb to 24.
- the color difference signal delay units 28 c and 29 c input the color difference signals Cb and Cr output from the color feature quantity calculation unit 31 to the multipliers 26 and 27, and the chroma conversion multiplier determination unit 24 to the multipliers 26 and 27. This is provided to synchronize with the input of the saturation conversion multiplier.
- the luminance signal delay unit 30 c receives the luminance signal YIN output from the color feature amount calculation unit 31 and inputs the color component value calculation unit 32 to the color components of the color difference signals CbM and CrM output from the multipliers 26 and 27. This is provided to synchronize with the input to the value calculation unit 32.
- the color component value calculation unit 32 receives the luminance signal Y input from the color feature amount calculation unit 31 via the luminance signal delay unit 30c and the color difference signals CbM and CrM input from the multipliers 26 and 27 from red, green, Blue color component values ROUT, GOUT, BOUT are calculated, and color signals ROUT, GOUT, BOUT representing the color component values ROUT, GOUT, BOUT are output from the output terminals 20r, 20g, 20b.
- the calculation of the saturation in the saturation calculation unit 22 is performed in the same manner as the calculation of the saturation in the color feature amount calculation unit 12 of the first embodiment.
- the generation of the saturation histogram HSTb in the saturation histogram generation unit 13b is performed in the same manner as the generation of the saturation histogram HSTb in the saturation histogram generation unit 13 of the second embodiment.
- the generation of the saturation conversion multiplier determination function Fb by the saturation conversion multiplier determination function generation unit 23 is performed in the same manner as the generation of the saturation conversion multiplier determination function Fb by the saturation conversion multiplier determination function generation unit 23 in the second embodiment. .
- the saturation signal delay unit 25 is the time required for the saturation histogram generation unit 13b and the saturation conversion multiplier determination function generation unit 23 to perform the above processing and output the saturation conversion multiplier determination function Fb (saturation signal).
- the saturation conversion multiplier is obtained by delaying the saturation signal SAe by the time from the input to the saturation histogram generation unit 13b of SAe until the output of the saturation conversion multiplier determination function Fb by the saturation conversion multiplier determination function generation unit 23).
- the saturation conversion multiplier determination function Fb (f) for a certain frame Fr (f) is input from the saturation conversion multiplier determination function generation unit 23 to the saturation conversion multiplier determination unit 24.
- the saturation signal SAe (f, x) of each pixel in the same frame is supplied to the saturation conversion multiplier determining unit 24.
- the determination of the saturation conversion multiplier by the saturation conversion multiplier determination unit 24 is performed in the same manner as the determination of the saturation conversion multiplier by the saturation conversion multiplier determination unit 24 in the second embodiment.
- the color difference signal delay units 28c and 29c convert the color difference signals Cb and Cr output from the color feature amount calculation unit 31 into a saturation calculation unit 22c, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, and
- the time required for processing in the color feature quantity calculation unit 31 from the time required for processing in the saturation conversion multiplier determination unit 24 (time from generation of the color signals RIN, GIN, BIN to generation of the saturation conversion multiplier Kb) (color signal) RIN, GIN, and BIN are subtracted by a time obtained by subtracting the time from the input of RIN, GIN, and BIN), and output to multipliers 26 and 27.
- the multiplication of the saturation conversion multiplier Kb by the multipliers 26 and 27 is performed in the same manner as the multiplication of the saturation conversion multiplier Kb by the multipliers 26 and 27 in the second embodiment, and is output from the multipliers 26 and 27.
- the obtained color difference signals CbM and CrM are supplied to the color component value calculation unit 32.
- the luminance signal delay unit 30c converts the luminance signal Y output from the color feature amount calculation unit 31 into a saturation calculation unit 22c, a saturation histogram generation unit 13b, a saturation conversion multiplier determination function generation unit 23, and a saturation conversion multiplier determination.
- the time required for processing in the color feature quantity calculation unit 31 from the time required for processing in the unit 24 and the multipliers 26 and 27 (time from the input of the color signals RIN, GIN, and BIN to the output of the saturation conversion multiplier Kb) (The time from the input of the signals RIN, GIN, and BIN to the output of the color difference signals Cb, Cr) is delayed by a time that is subtracted and output to the color component value calculation unit 32, whereby the multipliers 26 and 27 output the color component values.
- the color component value calculation unit 32 converts the luminance signal Y and the color difference signals CbM and CrM into red, green and blue color component values ROUT, GOUT and BOUT, and represents a color signal representing the color component values ROUT, GOUT and BOUT.
- ROUT, GOUT, and BOUT are output from the output terminals 20r, 20g, and 20b.
- the calculation of the red, green, and blue color component values ROUT, GOUT, and BOUT based on the luminance signal Y and the color difference signals CbM and CrM is performed by a generally performed method.
- the process of calculating the color component values of red, green, and blue from the luminance and color difference is relatively simple and can be realized with a relatively small circuit.
- the effect of the third embodiment will be described. Even if the input signal or the output signal is a color signal of red, green, or blue, since the calculation of hue or brightness is unnecessary as in the second embodiment, the scale of the circuit, specifically, the IC is reduced. . Thereby, cost reduction is possible.
- the color component values ROUT, GOUT, and BOUT are calculated using the converted saturation SAb generated by performing the saturation conversion by the saturation conversion unit 15.
- the color difference signals CbM and CrM are converted using the saturation conversion multiplier Kb, and the color component values ROUT, GOUT and BOUT are calculated using the converted color difference signals CbM and CrM. Saturation conversion is realized. That is, saturation conversion is realized without converting a signal representing the saturation SAe.
- the process of calculating the color component values of red, green, and blue from the luminance and color difference is relatively simple and can be realized with a relatively small circuit.
- the processing is relatively It is simple and the scale of the circuit for processing can be reduced.
- each part of the image processing apparatuses 10, 10b, and 10c (part illustrated as a functional block) is realized by a processing circuit.
- the processing circuit may be dedicated hardware or a CPU that executes a program stored in a memory.
- the functions of each part in FIG. 1, FIG. 6, or FIG. 10 may be realized by a processing circuit, or the functions of a plurality of parts may be realized by a processing circuit.
- the processing circuit When the processing circuit is a CPU, the function of each part of the image processing apparatus is realized by software, firmware, or a combination of software and firmware.
- Software or firmware is described as a program and stored in a memory.
- the processing circuit reads out and executes the program stored in the memory, thereby realizing the function of each unit.
- the image processing apparatus is a memory for storing a program in which the functions of the respective parts shown in FIG. 1, FIG. 6, or FIG. 10 are executed as a result when executed by the processing circuit. Is provided. These programs can also be said to cause a computer to execute a processing method or a procedure in an image processing method implemented by the image processing apparatus.
- each part of the image processing apparatus may be realized by dedicated hardware, and a part may be realized by software or firmware.
- the processing circuit can realize the functions described above by hardware, software, firmware, or a combination thereof.
- FIG. 11 shows an example of the configuration when the above processing circuit is a CPU and all the functions of the image processing apparatus are realized by a computer (indicated by reference numeral 50) including a single CPU, together with the display unit 40.
- the computer 50 and the display unit 40 constitute a video display device.
- a computer 50 shown in FIG. 11 includes a CPU 51, a memory 52, an input interface 53, and an output interface 54, which are connected by a bus 55.
- the input interface 53 receives a standard video signal that can be supported by an image display device such as a television or a computer.
- This video signal is composed of color signals RIN, GIN, and BIN in the first and third embodiments, and is composed of a luminance signal YIN and color difference signals CbIN, CrIN in the second embodiment. .
- the CPU 51 operates in accordance with a program stored in the memory 52, and processes each part of the image processing apparatus according to the first, second, or third embodiment on the video signal input via the input interface 53,
- the output signal obtained as a result of the above is output from the output interface 54 and supplied to the display unit 40.
- This output signal is composed of color signals ROUT, GOUT and BOUT in the first and third embodiments, and is composed of a luminance signal YOUT and color difference signals CbOUT and CrOUT in the second embodiment.
- the content of the processing by the CPU 51 is the same as that described in the first, second or third embodiment. Data generated in the course of processing is held in the memory 52.
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Abstract
Description
入力映像信号から各画素単位で彩度、色相、明度を算出する色特徴量算出部と、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成部と、
前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムから彩度変換関数を生成する彩度変換関数生成部と、
前記彩度変換関数生成部で生成された前記彩度変換関数により、各画素の前記彩度を変換して変換後の彩度を出力する彩度変換部と、
前記彩度変換部から出力された、前記変換後の彩度と、前記色特徴量算出部で算出された色相及び明度とから赤、緑、青の色成分値を算出する色成分値算出部とを備える
ことを特徴とする。
入力映像信号から各画素単位で彩度を算出する彩度算出部と、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成部と、
前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムから彩度変換乗数決定関数を生成する彩度変換乗数決定関数生成部と、
前記彩度変換乗数決定関数と前記入力映像信号で表される各画素の前記彩度とにより当該画素についての彩度変換乗数を決定する彩度変換乗数決定部と、
前記彩度変換乗数決定部により決定された前記各画素についての前記彩度変換乗数と、前記入力映像信号で表される同じ画素の色差とを乗算する乗算器とを備える
ことを特徴とする。
図1は、本発明の実施の形態1の画像処理装置10の構成を示すブロック図である。図示の画像処理装置10は、入力端子11r、11g、11bと、色特徴量算出部12と、彩度ヒストグラム生成部13と、彩度変換関数生成部14と、彩度変換部15と、彩度信号遅延部16と、色相信号遅延部17と、明度信号遅延部18と、色成分値算出部19と、出力端子20r、20g、20bとを備えている。
画像処理装置10と表示部40とで、映像表示装置が構成されている。
色特徴量算出部12は、算出した彩度SAaを表す信号(彩度信号)を彩度ヒストグラム生成部13に供給するとともに、彩度信号遅延部16を介して彩度変換部15に供給する。
色特徴量算出部12は、算出した色相HUaを表す信号(色相信号)及び明度VAaを表す信号(明度信号)を、それぞれ色相信号遅延部17及び明度信号遅延部18を介して色成分値算出部19に供給する。
彩度SAaを表す彩度信号は、該彩度と同じ符号SAaで示され、色相HUaを表す色相信号は、該色相と同じ符号HUaで示され、明度VAaを表す明度信号は、該明度と同じ符号VAaで示される。以下、他の信号についても同様である。
彩度変換関数生成部14は、彩度ヒストグラム生成部13から入力された彩度ヒストグラムHSTaから彩度変換関数Faを生成して、彩度変換部15に供給する。
彩度変換部15は、色特徴量算出部12から彩度信号遅延部16を介して入力された彩度SAaを上記彩度変換関数Faにより変換して、変換後の彩度SAbを色成分値算出部19に出力する。
色相信号遅延部17及び明度信号遅延部18は、色特徴量算出部12から出力された色相信号HUa及び明度信号VAaの色成分値算出部19への入力を、彩度変換部15から色成分値算出部19への彩度信号SAbの入力に同期させるために設けられたものである。
表示部40は、赤、緑、青の色信号ROUT、GOUT、BOUTに基づいて映像を表示する。
入力端子11r、11g、11bに入力される色信号RIN、GIN、BINは、各画素の赤、緑、青の色成分値を表すものである。
色特徴量算出部12は、入力端子11r、11g、11bに入力された色信号で表される色成分値RIN、GIN、BINから彩度SAa、色相HUa、及び明度VAaを算出する。この算出は、一般的に行われている計算により行われる。
彩度ヒストグラムHSTaの生成においては、彩度SAaを表す階調値の階級CLa毎の出現度数Daを一定の期間乃至範囲、例えば1フレームにわたり、計数する。階調値の出現度数とは、当該階調値を有する画素の出現度数を意味する。階級CLaにおける階調値の出現度数Daを「Da(CLa)」で表す。他の値についても同様である。階級CLaにおける階調値の出現度数を、単に階級CLaの度数と言うこともある。
各階級CLaは、1個の階調値から、又は相連続する複数個の階調値から成り、互いに重なり合わない。以下では各階級が1個の階調値から成る場合について説明する。この場合各階級は、該階級に属する彩度SAaの階調値によって特定される。
上記の上限値は、傾きの最大値と、階級の数の逆数と、ヒストグラムの生成に用いられた画素の数との積に対応し、上記の下限値は、傾きの最小値と、ヒストグラムの生成に用いられた画素の数との積に対応する。
2以上の他の階級への譲り渡しの際には、上限値を超えている分を分割し、各分割部分を他の階級に割り当て、割り当てられた階級では、当該階級の度数を割り当て分だけ多くし、注目階級CLaでは、当該割り当て分だけ度数を少なくする。このような処理を、割り当てられた他の階級のすべてについて行う結果、注目階級CLaでは、他の階級の割り当て分の合計だけ、度数が少なくなる。
2以上の他の階級からの譲り受けにおいては、足りない分を分割し、各分割部分を他の階級に割り当て、割り当てられた階級では、当該階級の度数を割り当て分だけ少なくし、注目階級CLaでは、当該割り当て分だけ度数を多くする。このような処理を、割り当てられた他の階級のすべてについて行う結果、注目階級CLaでは、他の階級の割り当て分の合計だけ、度数が多くなる。
このような譲り受けは、足りない分に相当する負の値を他の階級に譲り渡す処理であるとも言える。
図3(a)及び図3(b)はいずれも彩度SAaの平均値SAamは0.5であるが、彩度分布の形状は異なり、図3(a)では、入力彩度SAaが中彩度域に多く分布し、図3(b)では、入力彩度SAaが、中彩度域にはあまり存在せず、低彩度域及び高彩度域に多く分布している。また、図3(c)では入力彩度SAaが低彩度域に多く分布し、図3(d)では入力彩度SAaが高彩度域に多く分布している。
度数の再配分の具体的方法は、後に実施の形態2に関して説明される、彩度変換乗数決定関数の生成の際の度数の再配分の方法と同様であっても良い。
彩度ヒストグラム生成部13で各フレーム内の画素の彩度SAaに基づいて彩度ヒストグラムHSTaを生成する場合には、同じフレームの画素の彩度SAaに基づいて、当該フレームについての彩度変換関数Faの生成が行われることになる。
彩度ヒストグラム生成部13で複数のフレーム内の画素の彩度SAaに基づいて彩度ヒストグラムHSTaを生成する場合には、該複数のフレームの画素の彩度SAaに基づいて、当該フレームについての彩度変換関数Faの生成が行われることになる。
各フレームFr(f)についての彩度変換関数Faであることを強調するために符号Fa(f)を用いることがある。
符号「SAa(f,x)」はフレームFr(f)の各画素Px(x)の彩度信号であることを強調するために用いられている。このような強調が必要ない場合、あるいは、複数の画素の彩度信号に共通の説明に際しては単に符号SAaが用いられる。また、どのフレームの画素の彩度信号であるかを強調する必要がない場合には符号SAa(x)を用いる場合がある。他の符号についても同様である。
彩度変換部15で各フレームFr(f)の各画素の彩度SAa(f,x)を変換して、変換後の彩度SAb(f,x)を求める際には、同じフレームFr(f)について定められた彩度変換関数Fa(f)が用いられる。
色成分値ROUT、GOUT、BOUTの算出は、一般的に行われている方法で行われる。
また、再現を意図した色が多い中間彩度の領域の最大値を大きく設定することで、中間彩度の領域における色の違いを強調することができる。
さらに、最小値を設けることで、彩度の差が圧縮されて、色の違いが小さくなり過ぎるのを防ぐことができる。一方、最大値を設定することで、関数の値が急に変換するのを避けることができる。
例えば、色再現範囲が狭い表示装置では、濃い色(彩度の高い色)は表示できないが、一般的なコンテンツに多く含まれる中間的な色を濃く(より高い彩度で)表示するため、中間彩度領域の最小値を大き目に設定し、高彩度領域の最大値を小さめに設定することにより、図4(a)に示すように、中彩度領域から高彩度領域に掛けて、上に凸となる曲線が生成されやすくなる。
本発明は、入力映像に応じて彩度変換関数(該関数で表される曲線)を変化させることが特徴であるが、これとともに、該関数の傾きの最大値及び最小値の少なくとも一方を制御することで、彩度変換関数を表示装置の特性に適合するようにすることができる。
図6は、本発明の実施の形態2の画像処理装置10bの構成を示すブロック図である。図示の画像処理装置10bは、入力端子21y、21cb及び21crと、彩度算出部22と、彩度ヒストグラム生成部13bと、彩度変換乗数決定関数生成部23と、彩度変換乗数決定部24と、彩度信号遅延部25と、色差信号遅延部28、29と、輝度信号遅延部30と、乗算器26、27と、出力端子31y、31cb、31crとを備えている。
彩度変換乗数決定関数生成部23は、彩度ヒストグラム生成部13bから入力された彩度ヒストグラムHSTbから彩度変換乗数決定関数Fbを生成し、彩度変換乗数決定部24に出力する。
彩度変換乗数決定部24は、彩度算出部22から彩度信号遅延部25を介して入力された彩度信号SAcと、彩度変換乗数決定関数生成部23から入力された彩度変換乗数決定関数Fbとから、彩度変換乗数Kbを決定し、乗算器26、27に出力する。
入力端子11yに入力された輝度信号YINは、輝度信号遅延部30で遅延された後、出力輝度信号YOUTとして出力端子31yから出力される。
色差信号遅延部28及び29は、それぞれ入力端子21cb及び21crに入力された色差信号CbIN及び信号CrINの、乗算器26及び27への入力を、彩度変換乗数決定部24から乗算器26及び27への彩度変換乗数Kbの入力に同期させるために設けられたものである。
輝度信号遅延部30は、入力端子21yに入力された輝度信号YINの、出力端子31yへの出力を、乗算器26及び27から出力端子31cb及び31crへ出力色差信号CbOUT及びCrOUTの出力に同期させるために設けられたものである。
入力端子21yに入力される輝度信号YINは、各画素の輝度値を表すものである。入力端子21cb、21crに入力される色差信号CbIN、CrINは、各画素の色差成分値を表すものである。
彩度算出部22は、入力端子21y、21cb、21crに入力された輝度信号YIN、色差信号CbIN、CrINから彩度SAcを算出する。この算出は、一般的に行われている計算により算出する。
彩度ヒストグラムHSTbの生成においては、彩度SAcを表す階調値の階級CLb毎の出現度数Dbを一定の範囲、例えば1フレームにわたり、計数する。階級CLbの度数Dbを「Db(CLb)」で表す。
各階級CLbは、1個の階調値から、又は相連続する複数個の階調値から成り、互いに重なり合わない。以下では階調値が10ビットで表されて0から1023までの値を取り、16個の階級に分けられており、従って、各階級が64個の階調値から成る場合について説明する。
上記の上限値は、傾きの最大値と、ヒストグラムの生成に用いられた画素の数との積に対応し、上記の下限値は、傾きの最小値と、ヒストグラムの生成に用いられた画素の数との積に対応する。
2以上の他の階級への譲り渡しの際には、上限値を超えている分を分割し、各分割部分を他の階級に割り当て、割り当てられた階級では、当該階級の度数を割り当て分だけ多くし、注目階級CLbでは、当該割り当て分だけ度数を少なくする。このような処理を、割り当てられた他の階級のすべてについて行う結果、注目階級CLbでは、他の階級の割り当て分の合計だけ、度数が少なくなる。
2以上の他の階級からの譲り受けにおいては、足りない分を分割し、各分割部分を他の階級に割り当て、割り当てられた階級では、当該階級の度数を割り当て分だけ少なくし、注目階級CLbでは、当該割り当て分だけ度数を多くする。このような処理を、割り当てられた他の階級のすべてについて行う結果、注目階級CLbでは、他の階級の割り当て分の合計だけ、度数が多くなる。
このような譲り受けは、足りない分に相当する負の値を他の階級に譲り渡す処理であるとも言える。
図7の棒グラフが彩度ヒストグラムHSTbの階級毎の出現度数Dbを表し、折れ線が彩度変換乗数決定関数Fbの値SAdを表している。出現度数が多い箇所では、彩度変換乗数決定関数Fbの傾きが大きくなるように彩度変換乗数決定関数Fbが生成される。
この分配に当たっては、すべての階級に均等に割り当てても良く、より近い階級により多く割り当てても良い。そのようにしてできた新たな彩度分布(調整後のヒストグラム)を基に彩度変換乗数決定関数Fbを生成する。
彩度ヒストグラム生成部13bで各フレーム内の画素の彩度SAcに基づいて彩度ヒストグラムHSTbを生成する場合には、同じフレームの画素の彩度SAcに基づいて、当該フレームについての彩度変換乗数決定関数Fbの生成が行われることになる。
彩度ヒストグラム生成部13bで複数のフレーム内の画素の彩度SAcに基づいて彩度ヒストグラムHSTbを生成する場合には、該複数のフレームの画素の彩度SAcに基づいて、当該フレームについての彩度変換乗数決定関数Fbの生成が行われることになる。
各フレームFr(f)についての彩度変換乗数決定関数Fbであることを強調するために符号Fb(f)を用いることがある。
各フレームFr(f)の各画素の彩度SAc(f,x)から対応する彩度変換乗数Kb(f,x)を決定する際には、同じフレームFr(f)について定められた彩度変換乗数決定関数Fb(f)が用いられる。
図9に示した折れ線は、彩度変換乗数決定関数Fbを示している。折れ線の折れ点は、横軸方向位置が各階級の代表値を表し、縦軸方向位置が上記代表値に対応する、関数の値を表す。そして、折れ線上の各点に対応する入力彩度SAcに対する関数の値、即ち出力彩度SAd(=Fb(SAc))の比Ks(=SAd/SAc)が、当該入力彩度SAcに対する彩度変換乗数Kbを表す。
比Ks(x)の補間は下記の式(1)で表すことができる。
式(1)で、Da、Dbは、
Da=SAc(x)-SAca
Db=SAcb-SAc(x)
出力彩度SAd(x)の補間は下記の式(2)で表すことができる。
SAd(x)=(SAd(a)×Db+SAd(b)×Da)/(Da+Db)
(2)
Kb(x)=SAd(x)/SAc(x) (3)
また、再現を意図した色が多い中間彩度の領域の最大値を大きく設定することで、中間彩度の領域における色の違いを強調することができる。
さらに、最小値を設けることで、彩度の差が圧縮されて、色の違いが小さくなり過ぎるのを防ぐことができる。一方、最大値を設定することで、関数の値が急に変換するのを避けることができる。
例えば、色再現範囲が狭い表示装置では、濃い色(彩度の高い色)は表示できないが、一般的なコンテンツに多く含まれる中間的な色を濃く(より高い彩度で)表示するため、中間彩度領域の最小値を大き目に設定し、高彩度領域の最大値を小さめに設定することにより、図7に示すように、中彩度領域から高彩度領域に掛けて、上に凸となる曲線が生成されやすくなる。
本発明は、入力映像に応じて彩度変換乗数決定関数(該関数で表される曲線)を変化させることが特徴であるが、これとともに、該関数の傾きの最大値及び最小値の少なくとも一方を制御することで、彩度変換乗数決定関数を表示装置の特性に適合するようにすることができる。
実施の形態2では、彩度変換乗数Kbを用いて、色差信号CbIN、CrINを変換し、これにより彩度の変換を実現している。即ち、彩度SAcを表す信号の変換を行うことなく、彩度の変換を実現している。実施の形態2では、輝度YOUT及び色差GbOUT、CrOUTの算出のために、彩度の変換及び変換後の彩度に基づく計算のいずれをも必要としないので、処理が比較的簡単であり、処理のための回路の規模を小さくすることができる。
図10は、本発明の実施の形態3に係る画像処理装置10cの構成を示すブロック図である。図示の画像処理装置10cは、入力端子11r、11g、11bと、彩度算出部22と、彩度ヒストグラム生成部13bと、彩度変換乗数決定関数生成部23と、彩度変換乗数決定部24と、乗算器26、27と、色特徴量算出部31と、彩度信号遅延部25と、色差信号遅延部28、29と、輝度信号遅延部30と、色成分値算出部32と、出力端子20r、20g、20bとを備えている。
入力端子11r、11g、11bには、テレビ、コンピュータ等の画像表示装置が対応可能な規格の映像信号が入力される。本実施の形態では、映像信号は、例えば赤、緑、青の信号RIN、GIN、BINであるものとする。
図10の画像処理装置10cは、図2において、画像処理装置10の代わりに用い得るものである。そして、画像処理装置10と同様に、色信号RIN、GIN、BINで構成される映像信号を入力とし、色信号ROUT、GOUT、BOUTを出力する。従って、表示部40としては、画像処理装置10を用いる場合と同様に、色信号ROUT、GOUT、BOUTを入力とするものが用いられる。
彩度変換乗数決定関数生成部23は、彩度ヒストグラムHSTbから彩度変換乗数決定関数Fbを生成し、彩度変換乗数決定部24に出力する。
色差信号遅延部28c及び29cは、色特徴量算出部31から出力された色差信号Cb及びCrの、乗算器26及び27への入力を、彩度変換乗数決定部24から乗算器26及び27への彩度変換乗数の入力に同期させるために設けられたものである。
輝度信号遅延部30cは、色特徴量算出部31から出力された輝度信号YINの、色成分値算出部32への入力を、乗算器26及び27から出力された色差信号CbM及びCrMの色成分値算出部32への入力に同期させるために設けられたものである。
彩度算出部22における彩度の算出は、実施の形態1の色特徴量算出部12における彩度の算出と同様に行われる。
輝度信号Y及び色差信号CbM、CrMに基づく赤、緑、青の色成分値ROUT、GOUT、BOUTの算出は、一般的に行われている方法で行われる。輝度及び色差から赤、緑、青の色成分値を算出する処理は、比較的簡単であり、比較的小さい規模の回路で実現することができる。
実施の形態3では、彩度変換乗数Kbを用いて、色差信号CbM、CrMを変換し、変換後の色差信号CbM、CrMを用いて色成分値ROUT、GOUT、BOUTの算出を行うことで、彩度の変換を実現している。即ち、彩度SAeを表す信号の変換を行うことなく、彩度の変換を実現している。上記のように、輝度、色差から赤、緑、青の色成分値を算出する処理は、比較的簡単であり、比較的小さい規模の回路で実現することができる。このように、実施の形態3では、色成分値ROUT、BOUT、BOUTの算出のために、彩度の変換及び変換後の彩度に基づく計算のいずれをも必要としないので、処理が比較的簡単であり、処理のための回路の規模を小さくすることができる。
例えば、図1、図6、又は図10の各部分の機能をそれぞれ処理回路で実現してもよいし、複数の部分の機能をまとめて処理回路で実現しても良い。
このように、処理回路は、ハードウェア、ソフトウェア、ファームウェア、またはこれらの組み合わせによって、上述の各機能を実現することができる。
図11に示されるコンピュータ50は、CPU51と、メモリ52と、入力インターフェース53と、出力インターフェース54とを備え、これらはバス55で接続されている。
入力インターフェース53には、テレビ、コンピュータ等の画像表示装置が対応可能な規格の映像信号が入力される。この映像信号は、実施の形態1及び3の場合には、色信号RIN、GIN、BINで構成され、実施の形態2の場合には、輝度信号YIN、及び色差信号CbIN、CrINで構成される。
この出力信号は、実施の形態1及び3では色信号ROUT、GOUT、BOUTで構成され、実施の形態2では輝度信号YOUT、及び色差信号CbOUT、CrOUTで構成される。
Claims (20)
- 入力映像信号から各画素単位で彩度、色相、明度を算出する色特徴量算出部と、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成部と、
前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムから彩度変換関数を生成する彩度変換関数生成部と、
前記彩度変換関数生成部で生成された前記彩度変換関数により、各画素の前記彩度を変換して変換後の彩度を出力する彩度変換部と、
前記彩度変換部から出力された、前記変換後の彩度と、前記色特徴量算出部で算出された色相及び明度とから赤、緑、青の色成分値を算出する色成分値算出部とを備える
ことを特徴とする画像処理装置。 - 前記彩度変換関数生成部は、前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムの各階級の度数を、低い側から順に累積加算することで、前記彩度変換関数を生成する
ことを特徴とする請求項1に記載の画像処理装置。 - 前記彩度変換関数生成部は、前記度数の累積加算により得られる、各階級までの累積加算値を、当該階級の代表値に対応する前記彩度変換関数の値とすることで、前記彩度変換関数を生成することを特徴とする請求項2に記載の画像処理装置。
- 前記彩度変換関数生成部は、各階級の前記度数が予め定められた上限値を超えている場合には、超えている分を、他の階級に譲り渡し、該譲り渡し後の度数を用いて、前記累積加算値の算出を行うことを特徴とする請求項3に記載の画像処理装置。
- 前記彩度変換関数生成部は、各階級の前記度数が予め定められた下限値を下回る場合には、下回る分を、他の階級から譲り受け、該譲り受け後の度数を用いて、前記累積加算値の算出を行うことを特徴とする請求項3又は4に記載の画像処理装置。
- 前記彩度変換関数生成部で生成される前記彩度変換関数の傾きに対して、予め最大値及び最小値の少なくとも一方が設定されている
ことを特徴とする請求項1から3のいずれか1項に記載の画像処理装置。 - 前記彩度変換部は、前記彩度変換関数の、各画素の前記彩度に対応する値を、当該画素の前記変換後の彩度として出力する
ことを特徴とする請求項1から6のいずれか1項に記載の画像処理装置。 - 入力映像信号から各画素単位で彩度を算出する彩度算出部と、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成部と、
前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムから彩度変換乗数決定関数を生成する彩度変換乗数決定関数生成部と、
前記彩度変換乗数決定関数と前記入力映像信号で表される各画素の前記彩度とにより当該画素についての彩度変換乗数を決定する彩度変換乗数決定部と、
前記彩度変換乗数決定部により決定された前記各画素についての前記彩度変換乗数と、前記入力映像信号で表される同じ画素の色差とを乗算する乗算器とを備える
ことを特徴とする画像処理装置。 - 前記彩度変換乗数決定関数生成部は、前記彩度ヒストグラム生成部で生成された前記彩度ヒストグラムの各階級の度数を、低い側から順に累積加算することで、前記彩度変換乗数決定関数を生成する
ことを特徴とする請求項8に記載の画像処理装置。 - 前記彩度変換乗数決定関数生成部は、前記度数の累積加算により得られる、各階級までの累積加算値を、当該階級の代表値に対応する前記彩度変換乗数決定関数の値とすることで、前記彩度変換乗数決定関数を生成することを特徴とする請求項9に記載の画像処理装置。
- 前記彩度変換乗数決定関数生成部は、各階級の前記度数が予め定められた上限値を超えている場合には、超えている分を、他の階級に譲り渡し、該譲り渡し後の度数を用いて、前記累積加算値の算出を行うことを特徴とする請求項10に記載の画像処理装置。
- 前記彩度変換乗数決定関数生成部は、各階級の前記度数が予め定められた下限値を下回る場合には、下回る分を、他の階級から譲り受け、該譲り受け後の度数を用いて、前記累積加算値の算出を行うことを特徴とする請求項10又は11に記載の画像処理装置。
- 前記彩度変換乗数決定関数生成部で生成される前記彩度変換乗数決定関数の傾きに対して、予め最大値及び最小値の少なくとも一方が設定されている
ことを特徴とする請求項8から10のいずれか1項に記載の画像処理装置。 - 前記彩度変換乗数決定部は、前記彩度変換乗数決定関数の、各画素の前記彩度に対応する値の、前記彩度に対する比を、当該画素についての彩度変換乗数として抽出する
ことを特徴とする請求項8から13のいずれか1項に記載の画像処理装置。 - 前記入力映像信号が輝度信号及び色差信号で構成され、
前記彩度算出部は、前記輝度信号及び前記色差信号から前記彩度を算出し、
前記乗算器は、前記入力映像信号を構成する前記色差信号で表される色差に、前記彩度変換乗数を乗算する
ことを特徴とする請求項8から14のいずれか1項に記載の画像処理装置。 - 前記入力映像信号が赤、緑、青の色信号で構成され、
前記彩度算出部は、前記赤、緑、青の色信号から前記彩度を算出し、
前記赤、緑、青の色信号から輝度及び色差を算出する色特徴量算出部をさらに有し、
前記乗算器は、前記色特徴量算出部で算出された前記色差に、前記彩度変換乗数を乗算し、
前記色特徴量算出部で算出された前記輝度と、前記乗算器での乗算の結果得られた色差とから赤、緑、青の色成分値を算出する色成分値算出部をさらに有する
ことを特徴とする請求項8から14のいずれか1項に記載の画像処理装置。 - 入力映像信号から各画素単位で彩度、色相、明度を算出する色特徴量算出ステップと、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成ステップと、
前記彩度ヒストグラム生成ステップで生成された前記彩度ヒストグラムから彩度変換関数を生成する彩度変換関数生成ステップと、
前記彩度変換関数生成ステップで生成された前記彩度変換関数により、各画素の前記彩度を変換して変換後の彩度を出力する彩度変換ステップと、
前記彩度変換ステップから出力された、前記変換後の彩度と、前記色特徴量算出ステップで算出された色相及び明度とから赤、緑、青の色成分値を算出する色成分値算出ステップとを備える
ことを特徴とする画像処理方法。 - 入力映像信号から各画素単位で彩度を算出する彩度算出ステップと、
前記彩度から彩度ヒストグラムを生成する彩度ヒストグラム生成ステップと、
前記彩度ヒストグラム生成ステップで生成された前記彩度ヒストグラムから彩度変換乗数決定関数を生成する彩度変換乗数決定関数生成ステップと、
前記彩度変換乗数決定関数と前記入力映像信号で表される各画素の前記彩度とにより当該画素についての彩度変換乗数を決定する彩度変換乗数決定ステップと、
前記彩度変換乗数決定ステップにより決定された前記各画素についての前記彩度変換乗数と、前記入力映像信号で表される同じ画素の色差とを乗算する乗算ステップとを備える
ことを特徴とする画像処理方法。 - 請求項17又は18に記載の画像処理方法を各ステップの処理をコンピュータに実行させるためのプログラム。
- 請求項19に記載のプログラムを記録したコンピュータで読み取り可能な記録媒体。
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020520145A (ja) * | 2017-05-05 | 2020-07-02 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | 復号された高ダイナミックレンジ画像の彩度を最適化すること |
JP2021007482A (ja) * | 2019-06-28 | 2021-01-28 | 富士フイルム株式会社 | 医用画像処理装置及び内視鏡システム並びに医用画像処理装置の作動方法 |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020123917A (ja) * | 2019-01-31 | 2020-08-13 | 富士通株式会社 | 画像処理プログラム、画像処理装置及び画像処理方法 |
CN113483682B (zh) * | 2021-06-16 | 2023-05-19 | 苏州赛腾精密电子股份有限公司 | 一种基于机器视觉的缝隙测量方法及*** |
Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04248681A (ja) * | 1991-02-04 | 1992-09-04 | Nippon Telegr & Teleph Corp <Ntt> | カラー画像強調・弛緩処理方法 |
JPH1023279A (ja) * | 1996-06-28 | 1998-01-23 | Fuji Xerox Co Ltd | 画像処理装置 |
US6192149B1 (en) * | 1998-04-08 | 2001-02-20 | Xerox Corporation | Method and apparatus for automatic detection of image target gamma |
JP2004007301A (ja) * | 2002-06-03 | 2004-01-08 | Kddi Media Will Corp | 画像処理装置 |
JP2004007202A (ja) * | 2002-05-31 | 2004-01-08 | Fuji Photo Film Co Ltd | 画像処理装置 |
JP2008072252A (ja) * | 2006-09-12 | 2008-03-27 | Canon Inc | 画像処理装置およびその方法 |
Family Cites Families (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP4250214B2 (ja) | 1997-04-18 | 2009-04-08 | 富士フイルム株式会社 | 色変換方法 |
JP2000316095A (ja) | 1999-04-30 | 2000-11-14 | Matsushita Research Institute Tokyo Inc | 画像処理装置および画像処理方法 |
JP3631108B2 (ja) * | 2000-06-21 | 2005-03-23 | キヤノン株式会社 | 画像処理方法、装置および記録媒体 |
TWI231701B (en) * | 2001-06-14 | 2005-04-21 | Matsushita Electric Ind Co Ltd | Automatic tone correction device, automatic tone correction method, and tone correction program recording medium |
KR100453038B1 (ko) * | 2001-12-24 | 2004-10-15 | 삼성전자주식회사 | 컬러 영상의 채도 조절 장치 및 방법 |
BRPI0302384B1 (pt) | 2002-07-20 | 2018-06-19 | Samsung Electronics Co., Ltd. | "método para intensificar de forma adaptativa uma cor, e equipamento para intensificar de forma adaptativa a cor de uma imagem" |
EP1429551A3 (en) * | 2002-12-12 | 2006-02-08 | Samsung Electronics Co., Ltd. | Method and apparatus for generating illumination characteristic data around image display device, and method and apparatus for compensating for color variation using the method and apparatus |
JP3880553B2 (ja) * | 2003-07-31 | 2007-02-14 | キヤノン株式会社 | 画像処理方法および装置 |
JP4424216B2 (ja) * | 2004-03-30 | 2010-03-03 | セイコーエプソン株式会社 | 画像処理装置、画像処理方法、および、画像処理プログラム |
KR100612494B1 (ko) * | 2004-06-07 | 2006-08-14 | 삼성전자주식회사 | 칼러 영상의 채도 조절 장치 및 방법 |
JP2007104151A (ja) * | 2005-09-30 | 2007-04-19 | Sanyo Electric Co Ltd | 画像処理装置および画像処理プログラム |
US7734114B1 (en) * | 2005-12-07 | 2010-06-08 | Marvell International Ltd. | Intelligent saturation of video data |
TWI350701B (en) * | 2006-06-06 | 2011-10-11 | Realtek Semiconductor Corp | Method and apparatus for adjusting saturation level |
US7856141B2 (en) * | 2006-09-01 | 2010-12-21 | Mediatek Inc. | Method for adjusting saturation and contrast of an area of an image and apparatus thereof |
KR101321396B1 (ko) * | 2007-07-20 | 2013-10-25 | 삼성전자주식회사 | 영상의 색 향상 장치 및 이를 이용한 영상의 색 향상 방법. |
JP5116393B2 (ja) * | 2007-07-31 | 2013-01-09 | キヤノン株式会社 | 画像処理装置及び画像処理方法 |
CN101325663B (zh) * | 2008-07-25 | 2010-06-09 | 北京中星微电子有限公司 | 一种提高图像质量的方法和装置 |
CN101668108A (zh) * | 2008-09-05 | 2010-03-10 | 比亚迪股份有限公司 | 一种图像色彩饱和度的调节方法及*** |
JP4831173B2 (ja) | 2009-01-22 | 2011-12-07 | 株式会社日立製作所 | 映像表示装置 |
JP5669489B2 (ja) | 2009-10-15 | 2015-02-12 | オリンパス株式会社 | 画像処理装置、画像処理方法および画像処理プログラム |
JP6212713B2 (ja) * | 2013-01-17 | 2017-10-18 | パナソニックIpマネジメント株式会社 | 映像投写装置および映像投写方法 |
JP6287337B2 (ja) * | 2014-02-28 | 2018-03-07 | 富士ゼロックス株式会社 | 画像処理装置、画像処理方法、画像処理システムおよびプログラム |
-
2015
- 2015-05-29 US US15/517,117 patent/US10003720B2/en active Active
- 2015-05-29 CN CN201580065631.4A patent/CN107004249B/zh active Active
- 2015-05-29 WO PCT/JP2015/065497 patent/WO2016088393A1/ja active Application Filing
Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04248681A (ja) * | 1991-02-04 | 1992-09-04 | Nippon Telegr & Teleph Corp <Ntt> | カラー画像強調・弛緩処理方法 |
JPH1023279A (ja) * | 1996-06-28 | 1998-01-23 | Fuji Xerox Co Ltd | 画像処理装置 |
US6192149B1 (en) * | 1998-04-08 | 2001-02-20 | Xerox Corporation | Method and apparatus for automatic detection of image target gamma |
JP2004007202A (ja) * | 2002-05-31 | 2004-01-08 | Fuji Photo Film Co Ltd | 画像処理装置 |
JP2004007301A (ja) * | 2002-06-03 | 2004-01-08 | Kddi Media Will Corp | 画像処理装置 |
JP2008072252A (ja) * | 2006-09-12 | 2008-03-27 | Canon Inc | 画像処理装置およびその方法 |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020520145A (ja) * | 2017-05-05 | 2020-07-02 | コーニンクレッカ フィリップス エヌ ヴェKoninklijke Philips N.V. | 復号された高ダイナミックレンジ画像の彩度を最適化すること |
JP7313285B2 (ja) | 2017-05-05 | 2023-07-24 | コーニンクレッカ フィリップス エヌ ヴェ | 復号された高ダイナミックレンジ画像の彩度を最適化すること |
JP2021007482A (ja) * | 2019-06-28 | 2021-01-28 | 富士フイルム株式会社 | 医用画像処理装置及び内視鏡システム並びに医用画像処理装置の作動方法 |
JP7096788B2 (ja) | 2019-06-28 | 2022-07-06 | 富士フイルム株式会社 | 医用画像処理装置及び内視鏡システム並びに医用画像処理装置の作動方法 |
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