KR0152031B1 - Image signal encoding method and apparatus with image characteristics - Google Patents

Image signal encoding method and apparatus with image characteristics

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Publication number
KR0152031B1
KR0152031B1 KR1019940001426A KR19940001426A KR0152031B1 KR 0152031 B1 KR0152031 B1 KR 0152031B1 KR 1019940001426 A KR1019940001426 A KR 1019940001426A KR 19940001426 A KR19940001426 A KR 19940001426A KR 0152031 B1 KR0152031 B1 KR 0152031B1
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scan
pattern
sum
data
encoding
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KR1019940001426A
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KR950024590A (en
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김성태
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김광호
삼성전자주식회사
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    • 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
    • H04N19/129—Scanning of coding units, e.g. zig-zag scan of transform coefficients or flexible macroblock ordering [FMO]
    • 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
    • H04N19/102—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
    • H04N19/13—Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC]
    • 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
    • H04N19/134—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
    • H04N19/157—Assigned coding mode, i.e. the coding mode being predefined or preselected to be further used for selection of another element or parameter
    • H04N19/159—Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
    • 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
    • H04N19/10—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding
    • H04N19/189—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the adaptation method, adaptation tool or adaptation type used for the adaptive coding
    • H04N19/196—Methods or arrangements for coding, decoding, compressing or decompressing digital video signals using adaptive coding characterised by the adaptation method, adaptation tool or adaptation type used for the adaptive coding being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters

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  • Engineering & Computer Science (AREA)
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  • Signal Processing (AREA)
  • Computing Systems (AREA)
  • Theoretical Computer Science (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
  • Compression Or Coding Systems Of Tv Signals (AREA)

Abstract

본 발명은 영상특성에 따른 영상신호의 부호화방법 및 그 장치에 관한 것이다. 본 발명은 1프레임기간동안 8×8블럭내 수평ㆍ수직방향으로의 인접한 픽셀간의 차이값을 제곱하여 합산한 값들을 비교한다. 그래서, 수평방향으로의 제곱합이 수직방향제곱합보다 크거나 같으면 일반적으로 사용되는 지그재그스캔방식을 갖는 스캔-패턴을 선택하고, 수직방향으로의 제곱합이 수평방향제곱합보다 크면 수직방향으로 스캔순서가 몰린 스캔-패턴을 블럭의 스캔-패턴으로 정한다. 그런 다음 1프레임기간동안 정해진 블럭의 스캔-패턴중 가장 많이 선택된 스캔-패턴을 그 프레임의 스캔-패턴으로 결정한다. 그래서, 결정된 스캔-패턴에 따라 양자화된 계수를 스캔하여 부호화함으로써 본 발명은 비트발생량을 줄일 수 있는 효과를 제공한다.The present invention relates to a method and an apparatus for encoding a video signal according to video characteristics. The present invention compares the sum of squared difference values between adjacent pixels in the horizontal and vertical directions in an 8x8 block during one frame period. Therefore, if the sum of squares in the horizontal direction is greater than or equal to the vertical sum of squares, a scan-pattern having a commonly used zigzag scan method is selected. If the sum of the squares in the vertical direction is greater than the sum of the horizontal directions, the scan is driven in the vertical direction. Set the pattern as the scan-pattern of the block. Then, the scan-pattern with the most selected scan-pattern of the predetermined block for one frame period is determined as the scan-pattern of the frame. Thus, the present invention provides an effect of reducing the amount of bits generated by scanning and encoding quantized coefficients according to the determined scan-pattern.

Description

영상특성에 따른 영상신호의 부호화방법 및 그 장치Video signal encoding method and device therefor according to video characteristics

제1도는 본 발명이 적용된 동영상부호화장치를 나타내는 블럭도.1 is a block diagram showing a video encoding apparatus to which the present invention is applied.

제2(a)-(b)도는 [런,레벨]형태의 부호화 과정을 나타내는 스캔-패턴.2 (a)-(b) are scan-patterns showing an encoding process in the form of [run, level].

제3도는 제1도 장치에서 영상특성에 따른 스캔-패턴을 결정하기 위한 방법을 나타내는 흐름도.3 is a flowchart illustrating a method for determining a scan-pattern according to an image characteristic in the apparatus of FIG.

* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings

18 : 스캔-패턴결정부 19 : 가변장부호화부18: scan-pattern determination section 19: variable length coding section

본 발명은 영상특성에 따른 영상신호의 부호화방법 및 그 장치에 관한것으로, 보다 상세하게는, 데이타변환되기 이전에 영상데이타의 영상특성을 분석하여, 프레임단위의 스캔-패턴을 비트수가 적게 발생하도록 선택하고, 선택된 스캔-패턴에 따라 부호화하는 영상특성에 따른 영상신호의 부호화방법 및 그 장치에 관한 것이다.The present invention relates to a method and apparatus for encoding an image signal according to an image characteristic. More particularly, before the data conversion, an image characteristic of an image data is analyzed to generate a scan-pattern in a frame unit with a small number of bits. A method and apparatus for encoding an image signal according to an image characteristic selected and encoded according to a selected scan-pattern.

일반적으로 MPEG II동영상압축부호화시스템에서는 현재 부호화하고자 하는 영상데이타를 부호화하여 전송하거나, 영상데이타의 화면간 상관성이 매우 높은 것을 이용하여 프레임데이타간의 차신호를 부호화한다. 즉, 이전 화면으로부터의 움직임량에 의한 동벡터를 검출하고, 이 검출된 동벡터를 이용하여 얻어진 영상데이타와의 차신호를 이산코사인변환(Discrete Cosine Transform; DCT)한다. 이 변환계수들은 버퍼상태와 입력되는 영상데이타의 영상특성에 따라 결정되는 양자화레벨에 의해 양자화된다. 양자화된 변환계수들은 N×N 크기(size)의 2차원 주파수영역에서 표현되는 것으로, 주어진 스캔-패턴의 스캔순서에 따라 스캔하면서 [런,레벨]의 형태로 부호화한다. N×N 블럭을 스캔할 때 2차원 주파수공간의 저주파로서 고주파로 스캔하면서 런(run) 및 레벨을 한쌍으로 하여 부호화시킨다. 여기서, 런(run)은 0이 아닌 계수들간의 0의 발생횟수를 의미하며, 레벨(level)은 0이 아닌 계수의 절대값을 의미한다. N×N(여기서, N이 8인 경우) 크기의 주파수영역의 경우, 런은 0부터 63까지의 값들을 가질 수 있으며, 양자화된 변환계수가 -255부터 255까지의 정수값인 경우, 레벨은 1부터 255까지의 값이며 그 부호(sign)는 별도로 표시된다. 이와 같이 [런,레벨] 형태로 부호화된 데이타는 가변장부호화과정을 거쳐서 최종적인 부호화된 영상데이타를 얻게 된다.In general, the MPEG II video compression encoding system encodes and transmits video data to be encoded, or encodes a difference signal between frame data using a very high correlation between screens of video data. That is, a motion vector is detected by the amount of motion from the previous screen, and a discrete cosine transform (DCT) of the difference signal with the image data obtained using the detected motion vector is performed. These transform coefficients are quantized by the quantization level determined by the buffer state and the image characteristics of the input image data. The quantized transform coefficients are expressed in a two-dimensional frequency domain of N × N size, and are encoded in the form of [run, level] while scanning in the scan order of a given scan-pattern. When scanning an N × N block, a low frequency in a two-dimensional frequency space is scanned at a high frequency to encode a pair of runs and levels. Here, run means the number of occurrences of zero between nonzero coefficients, and level means the absolute value of nonzero coefficients. For a frequency domain of size N × N (where N is 8), the run can have values from 0 to 63, and if the quantized transform coefficient is an integer value from -255 to 255, the level is It is a value from 1 to 255 and its sign is indicated separately. As described above, the data encoded in the form of [run, level] is subjected to a variable length encoding process to obtain final encoded image data.

하지만, 종래에는 두가지 스캔-패턴을 제시하고, 그 중 하나를 임의로 선택하여 사용하였기 때문에 영상특성을 전혀 고려하지 못하는 문제점이 있었다.However, in the related art, two scan-patterns have been proposed and one of them has been arbitrarily selected, and thus there is a problem in that image characteristics are not considered at all.

따라서, 본 발명이 목적은 전술한 문제점을 해결할 수 있도록 데이타 변환되기 이전에 영상신호의 에너지분포특성을 예측하여 제시된 스캔-패턴 중 비트발생수가 적은 스캔-패턴을 선택하고, 그 선택된 스캔-패턴에 따라 영상신호를 부호화하는 방법을 제공함에 있다.Accordingly, an object of the present invention is to predict the energy distribution characteristics of an image signal before data conversion so as to solve the above-described problem, and select a scan pattern having a small number of bit occurrences among the proposed scan patterns, Accordingly, a method of encoding an image signal is provided.

본 발명의 다른 목적은 전술한 영상특성에 따른 영상신호의 부호화방법을 구현하기 위한 장치를 제공함에 있다.Another object of the present invention is to provide an apparatus for implementing a video signal encoding method according to the above-described video characteristics.

이와 같은 목적들을 달성하기 위한 본 발명의 영상특성에 따른 영상신호의 부호화방법은 프레임단위로 소정크기의 블럭데이타를 입력받는 단계와, 입력받은 블럭데이타의 수평방향과 수직방향으로 각각 인접한 픽셀간의 차이값을 구하는 단계와, 상기 수평방향으로 구한 차이값들과 수직방향으로 구한 차이값들을 각각 제곱하여 합산하는 단계와 상기 수평방향제곱합과 수직방향제곱합을 비교하여 양자화된 계수가 몰릴 방향을 예측하는 단계와, 복수개의 스캔-패턴중 예측된 방향에 해당하는 스캔-패턴을 선택하는 단계와, 프레임단위로 가장 많이 선택된 스캔-패턴을 프레임단위의 스캔-패턴으로 결정하는 단계, 및 상기 결정된 스캔-패턴에 따라 상기 양자화된 계수를 스캔하여 발생되는 데이타를 부호화하는 단계를 포함한다.According to an aspect of the present invention, there is provided a method of encoding an image signal according to an image characteristic of the present invention, the method comprising: receiving block data having a predetermined size in units of frames, and a difference between pixels adjacent in the horizontal and vertical directions of the received block data; Estimating a value, a squared sum of the difference values obtained in the horizontal direction, and a difference value obtained in the vertical direction, and predicting a direction in which the quantized coefficients are driven by comparing the sum of the horizontal and vertical directions. Selecting a scan-pattern corresponding to the predicted direction among the plurality of scan-patterns, determining the scan-pattern most selected in units of frames as a scan-pattern in units of frames, and the determined scan-pattern And encoding the data generated by scanning the quantized coefficients.

본 발명의 다른 목적을 달성하기 위한 본 발명의 영상특성에 따른 영상신호의 부호화장치는 프레임단위로 소정 크기의 블럭데이타를 입력받아, 각 블럭데이타의 영상특성을 판단하고, 그 영상특성에 해당하는 블럭의 스캔-패턴을 선택하여 가장 많이 선택된 스캔-패턴을 프레임단위의 스캔-패턴으로 결정하는 스캔-패턴결정부, 및 상기 스캔-패턴결정부에 의해서 결정된 프레임단위의 스캔-패턴에 따라 상기 양자화된 계수를 스캔하여 발생되는 데이타를 부호화하는 가변장부호화부를 포함한다.According to an aspect of the present invention, an apparatus for encoding an image signal according to an image characteristic of the present invention receives block data having a predetermined size in units of frames, determines an image characteristic of each block data, and corresponds to the image characteristic. A scan-pattern determination unit that selects a scan-pattern of a block to determine the most-selected scan-pattern as a scan-pattern in a frame unit, and the quantization according to the scan-pattern in a frame unit determined by the scan-pattern determiner And a variable length encoding unit for encoding the data generated by scanning the generated coefficients.

이하, 첨부한 도면들을 참조하여 본 발명의 바람직한 실시예를 상세히 기술하기로 한다.Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

제1도는 본 발명이 적용된 동영상부호화장치를 나타내는 블럭도이다. 도시한 바와 같이, 입력되는 디지탈영상데이타는 일정크기의 소블럭(예를 들면, 8×8픽셀 또는 16×16픽셀)으로 나누어져 들어온다. 그러면, 동추정부(16)는 이러한 입력블럭데이타에 대해 프레임메모리(15)에 저장된 이전 화면의 영상데이타중 현재 입력되는 블럭데이타에 대응되는 부분으로 부터의 운동을 예측하는 동벡터(MV)를 검출하는 동추정(Motion Estimation)을 행한다. 동보상부(17)는 동추정부(16)에서 얻어지는 동벡터(MV)를 이용하여 현재 블럭과 가장 가까운 이전 화면의 블럭을 추출하는 동보상(Motion Compensation)을 행한다. 그러면, 부호화과정은 현재 입력되는 블럭만을 처리하거나(인트라모드), 현재 입력블럭과 동보상된 블럭의 차신호를 처리한다(인터모드). 이러한 부호화과정은 N×N변환부(11), 양자화부(12) 및 가변장부호화부(19)에서 이루어지며, 프레임메모리(15)에 이전 프레임의 영상데이타를 저장하기 위해 역양자화부(13) 및 N×N역변환부(14)가 있다.1 is a block diagram showing a video encoding apparatus to which the present invention is applied. As shown, the input digital image data is divided into small blocks (e.g., 8x8 pixels or 16x16 pixels) of a predetermined size. Then, the motion estimation unit 16 detects a motion vector (MV) for predicting the motion from the portion of the image data of the previous screen stored in the frame memory 15 corresponding to the currently input block data with respect to the input block data. Motion Estimation is performed. The motion compensator 17 performs motion compensation by extracting the block of the previous screen closest to the current block by using the motion vector MV obtained from the motion estimation unit 16. The encoding process then processes only the currently input block (intra mode) or processes the difference signal of the block that has been compensated with the current input block (inter mode). This encoding process is performed by the N × N converter 11, the quantizer 12, and the variable length encoder 19, and the inverse quantizer 13 to store the image data of the previous frame in the frame memory 15. ) And an N x N inverse transform unit 14.

또한, 부호화되어 전송되는 신호의 비트레이트를 일정하게 유지하기 위하여 버퍼(20)를 제어한다. 버퍼의 오버플로우(Overflow)나 언더플로우(Underflow)를 방지하기 위하여 버퍼의 데이타누적상태에 따라 양자화기의 데이타발생량을 조절하기 위한 양자화레벨을 슬라이스(Slice)단위로 발생한다. 슬라이스 단위의 양자화레벨은 비율제어부(21)로 입력된다. 비율제어부(21)는 입력되는 영상데이타를 공급받아 영상특성을 판단하고, 그 영상특성에 따라 슬라이스단위의 양자화레벨을 가변하여 매크로블럭단위의 양자화 레벨로 발생하여 양자화부(12)로 공급한다. 상술의 설명은 일반적인 동영상부호화장치의 동작설명이고, 영상특성에 따라 스캔-패턴을 결정하기 위한 동작설명은 다음과 같다.In addition, the buffer 20 is controlled to maintain a constant bit rate of a signal that is encoded and transmitted. In order to prevent overflow or underflow of the buffer, a quantization level for controlling the amount of data generated by the quantizer is generated in units of slices according to the data accumulation state of the buffer. The quantization level in slice units is input to the ratio controller 21. The ratio controller 21 receives the input image data, determines the image characteristic, and varies the quantization level of the slice unit according to the image characteristic, generates the macroblock unit quantization level, and supplies it to the quantization unit 12. The above description is an operation description of a general video encoding apparatus, and an operation description for determining a scan pattern according to image characteristics is as follows.

우선, N×N변환부(11)로 입력되는 원 영상신호 도는 동보상된 영상과의 차신호를 입력받는 스캔-패턴결정부(18)는 8×8블럭데이타내의 수평방향과 수직방향 각각에 대해서 인접한 픽셀간의 차이값을 구한다 그런 다음, 블럭내 수평ㆍ수직방향 각각에 대해 구한 차이값을 제곱하여 합산한다. 즉, 하기 식(1)과 식(2)에 도시한 바와 같이 8×8블럭내의 수평방향과 수직방향에 대해 다음과 같이 나타낸다.First, the scan-pattern determination unit 18, which receives the difference signal from the original image signal or the synchronously compensated image, inputted to the NxN conversion unit 11, is provided in the horizontal and vertical directions in the 8x8 block data, respectively. The difference between adjacent pixels is calculated. Then, the difference obtained for each of the horizontal and vertical directions in the block is squared and summed. That is, as shown in the following formulas (1) and (2), the horizontal and vertical directions in the 8x8 block are expressed as follows.

여기서, x,y는 8×8블럭내의 수평방향과 수직방향 각각에 대한 좌표를 나타내며, Pxy는 블럭내(x,y)에서의 픽셀값이다.Here, x, y represents coordinates for each of the horizontal and vertical directions in an 8x8 block, and Pxy is a pixel value in the block (x, y).

스캔-패턴결정부(18)는 상기 식(1)과 식(2)에 의해서 구한 블럭내 수평ㆍ수직방향으로의 인접한 픽셀간의 제곱합들(Sum_sdx, Sum_sdy)을 비교해서, 큰 값을 갖는 방향에 따라 제2(a)도 내지 (b)도 중 하나의 스캔-패턴을 결정한다. 즉, 블럭내 데이타들이 수직방향쪽으로 보다 집중적으로 또는 보다 넓게 분포하여 수직방향의 제곱합(Sum_sdy)이 수평방향의 제곱합(Sum_sdx)보다 크면 제2(b)도에 도시된 수직방향으로 스캔순서가 집중될 수 있는 대체스캔(alternate scan)방식의 스캔-패턴2를 선택하고, 그 이외의 경우에는 제2(a)도에 도시된 지그재그스캔(zigzag scan)방식의 스캔-패턴1을 선택한다. 스캔-패턴결정부(18)는 1프레임동안 가장 많이 선택된 스캔-패턴을 결정하여 가변장부호화부(19)로 결정된 스캔-패턴을 알린다. 가변장부호화부(19)는 양자화부(12)로부터 인가되는 양자화된 변환계수들을 스캔-패턴결정부(18)에서 영상특성에 따라 결정한 스캔-패턴의 스캔순서에 따라 스캔하여 발생되는 [런,레벨] 데이타들을 가변장부호화한다.The scan-pattern determination unit 18 compares the sums of squares (Sum_sdx, Sum_sdy) between adjacent pixels in the horizontal and vertical directions in the block obtained by the above equations (1) and (2), and compares them to the direction having a large value. Accordingly, the scan pattern of one of the second (a) to (b) is determined. That is, if the data in the block are distributed more intensively or more widely in the vertical direction and the sum of squares in the vertical direction (Sum_sdy) is larger than the sum of the squares in the horizontal direction (Sum_sdx), the scan order is concentrated in the vertical direction as shown in FIG. 2 (b). An alternate scan type scan-pattern 2 may be selected, and in other cases, a zigzag scan type scan-pattern 1 is selected. The scan-pattern determination unit 18 determines the scan-pattern most selected during one frame and informs the scan-pattern determined by the variable length encoder 19. The variable length encoding unit 19 is generated by scanning the quantized transform coefficients applied from the quantization unit 12 according to the scan order of the scan-pattern determined by the scan-pattern determination unit 18 according to the image characteristics. Level] variable-length code the data.

제3도는 제1도 장치에서 영상특성에 따른 스캔-패턴결정방법을 나타내는 흐름도이다.3 is a flowchart illustrating a scan-pattern determination method according to an image characteristic in the apparatus of FIG. 1.

우선, 스캔-패턴결정부(18)는 8×8블럭데이타를 인가받는다(제 101단계). 입력된 8×8블럭데이타내 수평ㆍ수직방향으로의 인접한 픽셀간의 제곱합(Sum_sdx, Sum_sdy)을 상술한 식(1)과 식(2)에 도시한 바와 같이 구한다(제 102단계). 그런 다음, 수평ㆍ수직방향으로의 제곱합의 대소를 비교하여 입력된 데이타의 영상특성 즉, 블럭내 양자화된 변환계수들이 몰릴 방향을 예측한다(제 103단계). 수직방향제곱합(Sum_sdy)이 수평방향제곱합(Sum_sdx)보다 크면(Sum_sdy Sum_sdx), 블럭내 양자화된 변환계수들이 수직방향으로 몰릴 것으로 예측하여 제2(b)도에 도시한 바와 같은 스캔-패턴2의 선택횟수(scan_pattern2)를 1 증가시킨다(제 104단계). 반대로 작거나 같으면 (Sum_sdy ≤ Sum_sdx), 제2(a)도에 도시한 바와 같은 스캔-패턴1의 선택횟수(scan-pattern1)를 1 증가시킨다(제 105단계). 위의 과정이 한 프레임단위로 완료되었는지 체크한다(제 106단계). 체크결과 아직 한 프레임이 끝나지 않았으면 다시 제 101단계로 돌아가 8×8블럭데이타를 입력받아 단계를 반복수행한다. 그렇지 않고 한 프레임이 끝났으면 한 프레임동안 발생된 스캔-패턴1과 스캔-패턴2의 선택횟수를 비교한다(제 107단계). 스캔-패턴1의 선택횟수(scan-pattern1)와 스캔-패턴2의 선택횟수(scan-pattern2)보다 많거나 같으면(scan-pattern1 scan-pattern2), 스캔-패턴1로 결정하고,아니면 스캔-패턴2로 결정하여 부호화비트수를 줄인다.First, the scan-pattern determination unit 18 receives 8x8 block data (step 101). The sum of squares (Sum_sdx, Sum_sdy) between adjacent pixels in the horizontal and vertical directions in the input 8x8 block data is obtained as shown in Equations (1) and (2) (step 102). Then, by comparing the magnitudes of the sums of squares in the horizontal and vertical directions, the image characteristic of the input data, that is, the direction in which the quantized transform coefficients in the block are driven are predicted (step 103). If the sum of the sum of the vertical direction sums (Sum_sdy) is larger than the sum of the sum of the horizontal direction sums (Sum_sdy Sum_sdx), the quantized transform coefficients in the block are predicted to be driven in the vertical direction. The selection count scan_pattern2 is increased by one (step 104). On the contrary, if it is small or equal (Sum_sdy < RTI ID = 0.0 > Sum_sdx), < / RTI > the scan-pattern1 of the scan-pattern 1 as shown in FIG. It is checked whether the above process is completed in one frame unit (step 106). If the result of the check has not yet finished one frame, the process returns to step 101 and receives 8 × 8 block data and repeats the steps. Otherwise, if one frame is finished, the number of selections of the scan-pattern 1 and the scan-pattern 2 generated during one frame are compared (step 107). If it is greater than or equal to the number of selections of scan-pattern 1 (scan-pattern1) and the number of selections of scan-pattern 2 (scan-pattern2) (scan-pattern1 scan-pattern2), it is determined as scan-pattern 1 or scan-pattern Decide to 2 to reduce the number of encoded bits.

상술한 바와 같이, 본 발명의 영상특성에 따른 영상신호의 부호화방법 및 그 장치는, 영상특성에 상관없이 임의로 정해진 스캔-패턴에 따라 스캔하여 부호화하는 종래에 비해 1프레임기간동안 블럭내 양자화된 변환계수들이 몰릴 방향을 예측하여 스캔-패턴을 결정하고, 그 결정된 스캔-패턴에 따라 스캔하여 부호화함으로써 비트발생량을 줄일 수 있는 효과를 갖는다.As described above, the video signal encoding method and the apparatus according to the image characteristics of the present invention, the intra-block quantized transform for one frame period compared to the conventional scanning and encoding according to a predetermined scan-pattern irrespective of the image characteristics The scan pattern is determined by predicting the direction in which the coefficients are driven, and the bit generation amount is reduced by scanning and encoding the scan pattern according to the determined scan pattern.

Claims (3)

소정 크기의 블럭데이타를 입력받아 데이타변환하고, 변환된 계수를 양자화하여 부호화하는 동영상부호화장치에 있어서, 프레임단위로 상기 블럭데이타를 입력받아, 각 블럭데이타의 영상특성을 판단하고, 그 영상특성에 해당하는 블럭의 스캔-패턴을 선택하여 가장 많이 선택된 스캔-패턴을 프레임단위의 스캔-패턴으로 결정하는 스캔-패턴 결정부; 및 상기 스캔-패턴결정부에 의해서 결정된 프레임단위의 스캔-패턴에 따라 상기 양자화된 계수를 스캔하여 발생되는 데이타를 부호화하는 가변장부호화부를 포함하는 부호화장치.In a video encoding apparatus for receiving block data having a predetermined size, converting data, and quantizing and encoding the transformed coefficients, the video encoding apparatus receives the block data on a frame-by-frame basis to determine image characteristics of each block data, and to determine the image characteristics. A scan-pattern determination unit that selects a scan-pattern of a corresponding block to determine the most-selected scan-pattern as a scan-pattern in a frame unit; And a variable length encoding unit configured to encode data generated by scanning the quantized coefficients according to the scan-pattern of the frame unit determined by the scan-pattern determination unit. 제1항에 있어서, 상기 스캔-패턴결정부는 입력되는 각 블럭내 수평방향과 수직방향으로의 인접한 픽셀간의 차이값을 구하고, 그 차이값을 제곱하여 합산한 값을 서로 비교하여 큰 값을 가진 방향에 따라 스캔-패턴을 선택하는 것을 특징으로 하는 부호화장치.The method of claim 1, wherein the scan-pattern determination unit obtains a difference value between adjacent pixels in the horizontal direction and the vertical direction in each input block, and compares the sum of squared difference values to each other to have a larger value. And a scan pattern according to the encoder. 소정크기의 블럭데이타를 입력받아 데이타변환하고, 변환된 계수를 양자화하여 부호화하는 동영상부호화방법에 있어서, 프레임단위로 상기 블럭데이타를 입력받는 단계; 입력받은 블럭데이타의 수평방향과 수직방향으로 각각 인접한 픽셀간의 차이값을 구하는 단계; 상기 수평방향으로 구한 차이값들과 수직방향으로 구한 차이값들을 각각 제곱하여 합산하는 단계; 상기 수평방향제곱합과 수직방향제곱합을 비교하여 양자화된 계수가 몰릴 방향을 예측하는 단계; 복수개의 스캔-패턴중 예측된 방향에 해당하는 스캔-패턴을 선택하는 단계; 프레임단위로 가장 많이 선택된 스캔-패턴을 프레임단위의 스캔-패턴으로 결정하는 단계; 및 상기 결정된 스캔-패턴에 따라 상기 양자화된 계수를 스캔하여 발생되는 데이타를 부호화하는 단계를 포함하는 영상특성에 따른 영상신호의 부호화방법.A video encoding method of receiving block data having a predetermined size, converting data, and quantizing and encoding the transformed coefficients, the video encoding method comprising: receiving the block data in units of frames; Obtaining a difference value between adjacent pixels in the horizontal and vertical directions of the input block data; Squaring and summing the difference values obtained in the horizontal direction and the difference values obtained in the vertical direction, respectively; Comparing the horizontal direction sum with the vertical direction sum to predict a direction in which the quantized coefficients will be driven; Selecting a scan pattern corresponding to the predicted direction among the plurality of scan patterns; Determining the scan-pattern most selected on a frame basis as a scan-pattern on a frame basis; And encoding data generated by scanning the quantized coefficients according to the determined scan-pattern.
KR1019940001426A 1994-01-27 1994-01-27 Image signal encoding method and apparatus with image characteristics KR0152031B1 (en)

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