JP2005204247A - Motion picture compression apparatus and method, and motion picture transmission system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motion picture compression apparatus, motion picture transmission system, and motion picture compression method, in which high-speed processing can be performed by simple arithmetic processing without delay caused by processing. <P>SOLUTION: With regard to values of Y corresponding to pixels in frames of motion picture data imparted via a memory 23, a Y processing part 31 of an arithmetic processing section 25 sequentially creates processing values of Y by discarding low-order (8-N) bits (N is a number of 6, 7 or 8). With regard to values of U and values of Y corresponding to pixels in said frames, U and V processing parts 33 and 35 sequentially create processing values of U and Y by discarding low-order 3 bits. A transmission data constitution part 37 constitutes compression data on the basis of the created values of Y, U and V and imparts said data to a communication part 27. With regard to processing values of Y, compression data are constituted by appropriately using a differential value from a minimum value (or maximum value) of processing values of Y in macro blocks set in the frames. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a moving image compression apparatus, a moving image transmission system, and a moving image compression method, and more particularly to a vehicle.

  For example, when a moving image of an in-vehicle camera is displayed on a display device in a vehicle interior to monitor the periphery of the vehicle, how to transmit the moving image of the in-vehicle camera to a display device in the vehicle compartment becomes a problem.

  As a technique for transmitting a moving image captured by a camera as described above, there is a method of transmitting it as an analog signal. However, since analog wire transmission has low noise resistance, it is necessary to use an expensive shield wire for noise countermeasures, and there are drawbacks in terms of noise resistance and the cost of transmission cables. In addition, analog wireless transmission requires a high S / N ratio, and there is a drawback that a moving image is disturbed as soon as the S / N ratio decreases.

  Therefore, in order to overcome such drawbacks of analog transmission, a method of transmitting a moving image as a digital signal may be employed. This digital transmission requires a large data transfer rate (12 bits per pixel, image size 320 × 240, approximately 26 Mbps for 30 frames / second) when moving image data is transmitted uncompressed. Data transmission using a compression technique is performed.

  Conventional techniques relating to this moving picture compression / contraction technique include compression techniques using inter-frame compression, DCT (discrete cosine transform), Wavelet transform, and the like.

  In addition, as a prior art relevant to this invention, there exists a thing of patent document 1, for example.

Japanese Patent Application Laid-Open No. 61-144989

  However, since inter-frame compression is performed over a series of frames, several frames are required for compression and decompression, and the time from when a moving image is captured by the camera to when it is displayed is displayed. There is a problem that it takes. In particular, when monitoring the surroundings of a vehicle using moving images captured by the on-board camera, it is necessary to display the moving images around the vehicle that change from moment to moment in real time in the vehicle interior. It is not preferable that a delay occurs in the process from imaging to display.

  In the inter-frame compression, when the information of the previous frame is not correctly transmitted due to a communication problem or the like, the influence may be extended to the subsequent frame and the state in which the image is deteriorated may be prolonged.

  In addition, since DCT and Wavelet conversion require complicated arithmetic processing and a coefficient conversion table, the hardware scale increases and the cost increases.

  Therefore, the problem to be solved by the present invention is that it can be processed at high speed without causing a delay due to a simple arithmetic processing, and an abnormal transmission of information generated in one frame affects the subsequent frames. It is an object to provide a moving image compression apparatus, a moving image transmission system, and a moving image compression method that can prevent the above.

Means for solving the above-described problems include N- _Y bit Y value corresponding to the luminance signal, N- _U U value corresponding to the difference between the luminance signal and the red component, and the difference between the luminance signal and the blue component. a moving picture compression apparatus for compressing moving picture data represented by using the value of V in the N _V bit corresponding to the value of Y for each pixel in each frame of the input the moving image data has been For _Y , the lower M _Y bit part (where M _Y is an integer greater than or equal to 0 and less than N _Y ) is rounded down or rounded off, leaving only the remaining upper (N _Y -M _Y ) bit part and the processing value of Y a first processing unit that creates, for the value of U for each pixel in each frame of the input the moving image data, the lower M _U bit portion (where, M _U is 1 or more, less than N _U the remaining upper and truncated or rounded to integer) (N _U -M _U) bit A second processing section for creating a processed value of U leaving minute only for values of V corresponding to each pixel in each frame of the input the moving image data, the lower M _V bit portion (However, M _V is 1 or more, and a third processing unit for creating a processed value of V leaving only remaining upper (N _V -M _V) bit portion is truncated or rounded to an integer) of less than N _V, the first Compression that compresses the moving image data based on the Y processing value, the U processing value, and the V processing value created by one processing unit, the second processing unit, and the third processing unit And a fourth processing unit constituting data.

Preferably, the value of the M _U and the M _V is better to be set larger than the value of the M _Y.

  Preferably, the fourth processing unit further applies, to each pixel block in the pixel block, each pixel block having a size of Ma pixels in the vertical direction and Mb pixels in the horizontal direction set in advance in each frame. A minimum value or a maximum value is extracted from the corresponding Y processing values, and for at least some of the pixels in each pixel block, instead of the Y processing values corresponding to the at least some pixels In addition, the compressed data may be configured based on a difference value of the Y processing value with respect to the minimum value or the maximum value and the minimum value or the maximum value.

  Preferably, the fourth processing unit further uses the difference value or the processing value itself for the configuration of the compressed data for the Y component of each pixel in each pixel block. The difference value may be determined based on the number of bits for difference value set in advance for each pixel.

  Preferably, the fourth processing unit further uses either the minimum value or the maximum value for the configuration of the compressed data, and if the minimum value or the maximum value is adopted, The difference value corresponding to each pixel in the pixel block may be determined for each pixel block based on whether the number of the difference values adapted to the number of bits for difference value is larger.

  Preferably, the second processing unit and the third processing unit are configured to process the U processing value and the V processing value at a rate of one frame out of every two frames constituting the moving image. The fourth processing unit is configured to process the Y processing value for the frame in which the U processing value and the V processing value are generated by the second processing unit and the third processing unit, For the frame that forms the compressed data based on the U processing value and the V processing value, and the U processing value and the V processing value are not created by the first processing unit, the U processing The compressed data may be configured without using the value and the processing value of V.

  Preferably, the second processing unit creates the U processing value at a rate of one frame out of every two frames constituting the moving image, and the third processing unit Of the frames constituting the moving image, V is used for a frame in which the second processing unit does not create the U processing value by alternately operating with the second processing unit at a rate of one frame per two frames. The fourth processing unit generates the Y processing value other than the V processing value and the U for the frame in which the U processing value is generated by the second processing unit. For the frame in which the compressed data is configured using the processing value of V and the processing value of V is generated by the third processing unit, the processing value of Y and the processing of V other than the processing value of U Configure the compressed data using values Good.

  Preferably, a fifth processing unit that transmits the compressed data configured by the fourth processing unit via a predetermined transmission path is further provided.

  The means for solving the problem is a moving picture transmission system for a vehicle, wherein the moving picture compression apparatus according to claim 7 and the compressed data transmitted by the moving picture compression apparatus are transmitted through the transmission path. And an image expansion device that reconstructs moving image data based on the received compressed data.

Further, means for solving the above-mentioned problems include N _Y bit Y value corresponding to the luminance signal, N _U bit U value corresponding to the difference between the luminance signal and the red component, the luminance signal and the blue component. A moving image compression method for compressing moving image data expressed using a numerical value of V of N _V bits corresponding to the difference between Y and Y corresponding to each pixel in each frame of the input moving image data For the value of _Y , the lower M _Y bit part (where M _Y is an integer greater than or equal to 0 and less than N _Y ) is rounded down or rounded off, leaving only the remaining upper (N _Y -M _Y ) bit part and processing of Y a first processing step of generating a value for the value of U for each pixel in each frame of the input the moving image data, the lower M _U bit portion (where, M _U is 1 or more, N _U the remaining upper and truncation or rounding the integer) of less than (N _U -M _U A second processing step and the input value of V corresponding to each pixel in each frame of the moving image data to create a processed value of U, leaving only the bit portions, the lower M _V bit portion (where , M _V is an integer less than or equal to 1 and less than N _V ), and rounds off or rounds off, leaving only the remaining high-order (N _V −M _V ) bit part to create a V processing value, The moving image data is compressed based on the Y processing value, the U processing value, and the V processing value created in the first processing step, the second processing step, and the third processing step. And a fourth processing step that constitutes the compressed data.

Also, preferably, the value of the M _U and the M _V is better to be set larger than the value of the M _Y.

  Preferably, in the fourth processing step, for each pixel block having a size of Ma pixels in the vertical direction and Mb pixels in the horizontal direction set in advance in each frame, all pixels in the pixel block are set. A minimum value or a maximum value is extracted from the corresponding Y processing values, and for at least some of the pixels in each pixel block, instead of the Y processing values corresponding to the at least some pixels In addition, the compressed data may be configured based on a difference value of the Y processing value with respect to the minimum value or the maximum value and the minimum value or the maximum value.

  Preferably, in the fourth processing step, for the Y component of each pixel in each pixel block, whether the difference value or the processing value itself is used for the configuration of the compressed data, The difference value may be determined based on the number of bits for difference value set in advance for each pixel.

  Preferably, in the fourth processing step, whether the minimum value or the maximum value is used for the configuration of the compressed data, and if the minimum value or the maximum value is used, The difference value corresponding to each pixel in the pixel block may be determined for each pixel block based on whether the number of the difference values adapted to the number of bits for difference value is larger.

  According to the invention described in claims 1 and 10, the Y, U, and V values are simply processed by rounding down or rounding off the lower bits (the Y value may be left as it is), and for each frame. Since compression is performed independently, it is possible to perform high-speed processing without causing a delay of moving images due to the compression processing (for example, a delay caused by compression processing or the like in the process from imaging to display). Thus, for example, even when a moving image around the vehicle captured by the in-vehicle camera is compressed and transmitted, the moving image can be displayed in the vehicle interior in real time.

  In addition, since compression processing is performed independently for each frame, even if the information of one of the frames is not transmitted correctly due to a problem such as communication, the transmission abnormality of the information that occurred in that frame will be It is possible to avoid problems such as a prolonged state in which image degradation or the like has occurred due to the influence on the image quality.

  According to the second and eleventh aspects of the present invention, the number of digits for deleting the number of bits of the U and V components, which has less influence on the image quality than the Y component, is made larger than that of the Y component, thereby degrading the image quality. The compression rate can be increased while suppressing.

  According to the invention described in claims 3 and 12, for at least some of the pixels in each pixel block of each frame, instead of the processing value of Y corresponding to at least some of the pixels, the pixel block Since the compressed data is configured based on the difference value of the Y processing value with respect to the minimum value or the maximum value of the Y processing value in the middle, and the minimum value or the maximum value, the pixel to which the difference value is applied is effectively selected. Thus, the compression rate can be improved.

  According to the fourth and thirteenth aspects of the present invention, it is possible to easily and accurately determine whether or not to apply a difference value to the Y component of each pixel in the pixel block.

  According to the fifth and fourteenth aspects of the present invention, it is possible to easily and accurately determine which of the minimum value or the maximum value of the Y processing values is used for the configuration of the compressed data in each pixel block.

  According to the sixth aspect of the present invention, the compressed data is formed by omitting the U processing value and the V processing value at a rate of one frame per two frames. Can be further reduced.

  According to the seventh aspect of the present invention, the compressed data is formed by omitting the U processing value and the V processing value at a rate of one frame per two frames. Can be further reduced.

  In addition, since the data length of each frame after compression is averaged, the size of the transmission / reception buffer can be easily optimized.

  According to the eighth aspect of the present invention, compressed data obtained by compressing moving image data can be transmitted to a predetermined destination via a transmission path.

  According to the ninth aspect of the present invention, it is possible to perform high-speed compression processing and transmission without causing a delay of the moving image due to the compression processing (for example, a delay caused by the compression processing in the process from imaging to display). .

<First Embodiment>
FIG. 1 is a block diagram of a vehicle periphery monitoring device to which a moving image transmission system according to a first embodiment of the present invention is applied. As shown in FIG. 1, the vehicle periphery monitoring device includes a camera unit 1, a control device 3, and a display device 5. The camera unit 1 is installed in a vehicle and images a blind spot area around the vehicle. The display device 5 is installed in the passenger compartment and displays a peripheral image taken by the camera unit 1. The control device 3 controls the camera unit 1 and the display device 5 and causes the display device 5 to display an image captured by the camera unit 1. Since the control device 3 is installed at a location in the vehicle that is distant from the camera unit 1 (for example, around the display device 5 in the vehicle interior), the control unit 3 compresses the moving image data of the camera unit 1 and converts the cable (transmission path) 7 Is transmitted to the control device 3 via

  The camera unit 1 includes an imaging unit 11 that performs imaging, and a transmission processing unit 13 that performs transmission processing of moving image data and the like. The control device 3 includes a transmission processing unit 15 that performs transmission processing of moving image data and the like, and a control unit 17 that controls the entire vehicle periphery monitoring device including control of display contents of the display device 5. Among these, the transmission processing unit 13 of the camera unit 1 corresponds to the moving picture compression device according to the present invention, and the transmission processing unit 15 of the control device 3 corresponds to the image expansion device according to the present invention. The transmission processing units 13 and 15 correspond to the moving image transmission system according to the present invention.

  As shown in FIG. 2, the transmission processing unit 13 of the camera unit 1 includes a preprocessing unit 21, a memory 23, an arithmetic processing unit 25 including a CPU and the like, and a communication unit 27. As functional elements of the arithmetic processing unit 25, a Y processing unit (first processing unit) 31, a U processing unit (second processing unit) 33, a V processing unit (third processing unit) 35, and transmission And a data configuration unit (fourth processing unit) 37. The communication unit 27 corresponds to a fifth processing unit according to the present invention.

  The imaging unit 11 of the camera unit 1 is configured to include a lens system (not shown) and an imaging element such as a CCD, and sends an image signal around the captured vehicle to the transmission processing unit 13.

  The preprocessing unit 21 of the transmission processing unit 13 performs various kinds of preprocessing necessary for the image signal sent from the imaging unit 11 before compression processing. The preprocessing includes, for example, conversion processing to a digital signal when the image signal is an analog signal, conversion processing to a YUV format when the format of the image signal is not YUV format, and the like.

  The memory 23 functions as a frame memory that sequentially stores moving image data sent from the preprocessing unit 21 for at least one frame. The recorded contents of the memory 23 are sequentially updated as new frames are input.

Before describing the image compression processing by the arithmetic processing unit 25, the format of moving image data assumed in the present embodiment will be described. The technique according to this embodiment corresponds to the numerical value Y of N _Y bits corresponding to the luminance signal, the numerical value U of N _U bits corresponding to the difference between the luminance signal and the red component, and the difference between the luminance signal and the blue component. it is intended to compress the moving picture data represented by using a value of N _V bit V,. Note that the values of N _Y , N _U , and N _V are not necessarily the same.

More specifically, the image size is assumed to be QVGA (320 × 240 pixels), the color space of the image to be compressed is assumed to be the YUV420 format, and the number of bits per component is any of Y, U, and V. 8 bits are assumed (ie, N _Y , N _U , N _V = 8), so the number of bits per pixel is as shown in FIG.
8 (Y) +8/4 (U) +8/4 (V) = 12 bits. In this embodiment, the case where the format of moving image data to be transmitted is the YUV420 format will be described. However, the compression technique according to this embodiment can be applied to other YUV formats such as YUV411, and the image size Is not limited to QVGA.

  Further, in the present embodiment, as shown in FIG. 4, each macro having a size of Ma pixels in the vertical direction and Mb pixels in the horizontal direction (4 × 4 size in the example of FIG. 4) set in advance in each frame. A compression process and a transmission process for moving image data are performed with a block (pixel block) MBa as one unit. Note that if the size of the macroblock MBa is excessively large, a difference with respect to a reference value (maximum value or minimum value) of each processing value of a Y component to be described later becomes large. Therefore, it is necessary to set the macroblock MBa to an appropriate size. is there. For example, in the case of the macro block MBa, since the size is 4 × 4, 80 blocks are set per line.

  The Y processing unit 31 of the arithmetic processing unit 25 uses the lower (8-N) bits (N is 6, N) for the Y value corresponding to each pixel in each frame of the moving image data given via the memory 23. The number of 7 or 8) is rounded down or rounded off (in this case, rounded down), and the processing value of Y is sequentially created leaving only the upper N bits, and sent to the transmission data configuration unit 37.

  The U processing unit 33 rounds down or rounds the lower 1, 2, or 3 bits (here, 3 bits) of the U value corresponding to each pixel in each frame of the moving image data given via the memory 23. (Truncated here), the U processing values are sequentially created, leaving only the upper 5, 6 or 7 bits (here, the upper 5 bits), and sent to the transmission data configuration unit 37.

  The V processing unit 35 rounds down or rounds the lower 1, 2, or 3 bits (here, 3 bits) of the V value corresponding to each pixel in each frame of the moving image data given via the memory 23. (Here, rounded down), the V processing values are sequentially created, leaving only the upper 5, 6 or 7 bits (here, the upper 5 bits), and sent to the transmission data configuration unit 37.

  The transmission data configuration unit 37 configures compressed data obtained by compressing moving image data based on the Y, U, and V processing values created by the processing units 31, 33, and 35, and supplies the compressed data to the communication unit 27.

  The communication unit 27 transmits the compressed data given from the transmission data configuration unit 37 to the transmission processing unit 15 of the control device 3 via the cable 7. Data transmission between the communication unit 27 and the transmission processing unit 15 is performed by, for example, wired communication by cable connection as shown in FIG. 1 or wireless communication.

  Next, a specific example of moving image data compression processing in the present embodiment will be described. In this specific example, as shown in FIG. 4, a 4 × 4 macro block MBa is set in each frame of moving image data, and compression processing and transmission processing are performed with this macro block MBa as one unit. In FIG. 4, the subscripts attached to Y, U, and V identify which pixel in the macroblock MBa the Y, U, and V values correspond to. For example, two subscripts (0 to 3, 0 to 3) attached to Y correspond to the identification numbers of the pixels in the macroblock MBa, and subscripts (0 to 3) attached to U and V. ) Corresponds to the identification number of each pixel group in the macroblock MBa (four pixels form one set).

  In this specific example, as shown in FIG. 5, the Y processing unit 31 truncates the lower 2 bits for each Y value and leaves the upper 6 bits as the Y processed value. Further, the U processing unit 33 and the V processing unit 35 round down the lower 3 bits for each U and V value, and leave the upper 5 bits as the U and V processing values. Based on the Y, U, and V processing values thus created, the transmission data construction unit 37 composes compressed data in the format shown in FIG. 6, and the compressed data is transmitted to the control device 3 by the communication unit 27. Is done.

  The compressed data in FIG. 6 will be briefly described. Each macro block MBa of each frame F is grouped as a 1st to 60th block line BL for each line (one block line BL constitutes one packet). In each block line BL, the header BLH and the 6-bit line number data BLN indicating the block line number are followed by the data (1 to 80) of macroblocks MBa included in the block line BL ( 144 bits are assigned to each macro block MBa).

  In the data of each macro block MBa, the processing values of Y, U, and V corresponding to each pixel in the macro block MBa are shown following the 8-bit block number data MBN indicating the number of the macro block MBa. 6 in the order of description.

  The transmission processing unit 15 of the control device 3 receives the compressed data sequentially sent from the camera unit 1 via the cable 7, decompresses the compressed data, reconstructs the moving image data, and sends it to the control unit 17. give. More specifically, for each Y, U, V processing value corresponding to each pixel of each macroblock MBa included in each frame F, a zero value is sequentially assigned to the lower bits that are rounded down, and rounded down. The decompression process is performed by restoring the lower bits. For example, a 2-digit low-order bit of 00 is assigned to the Y processed value, and a 3-digit low-order bit of 000 is assigned to the U and V processed values.

  The control unit 17 causes the display device 5 to display an image corresponding to the moving image data based on the moving image data given from the transmission processing unit 15.

  As described above, according to the present embodiment, the Y, U, and V values are compressed by a simple process of rounding down or rounding down the lower bits and independently for each frame. Processing (compression, transmission, decompression) can be performed at high speed without causing image delay (for example, delay caused by compression processing or the like in the process from imaging to display). Thereby, the moving image around the vehicle imaged by the imaging unit 11 can be displayed in the vehicle interior in real time.

  In addition, since compression processing is performed independently for each frame, even if the information of one of the frames is not transmitted correctly due to a problem such as communication, the transmission abnormality of the information that occurred in that frame will be It is possible to avoid problems such as a prolonged state in which image degradation or the like has occurred due to the influence on the image quality.

  Also, by increasing the number of bits for deleting the number of bits of U and V components, which has less influence on the image quality than the Y component, than the Y component, it is possible to increase the compression rate while suppressing image quality deterioration.

Second Embodiment
A video transmission system according to the second embodiment of the present invention will be described below. The video transmission system according to the present embodiment is substantially different from the video transmission system according to the first embodiment described above only in the image compression format, and the hardware configuration is the above-described FIG. 1 and FIG. The configuration is the same.

  In this embodiment, as shown in FIG. 7, an 8 × 8 macroblock MBb is set. The two subscripts (0 to 15, 0 to 3) attached to Y in FIG. 7 correspond to the identification numbers of the pixels in the macroblock MBb, and the subscripts (0 to 0) attached to U and V. 15) corresponds to the identification number of each pixel group in the macroblock MBb.

  Except for the difference in the size of the macroblock MBb, the processing contents are substantially the same as in the first embodiment. The Y processing unit 31 cuts off the lower 2 bits for each Y value, and converts the upper 6 bits to Y. The U processing unit 33 and the V processing unit 35 discard the lower 3 bits of each U and V value and leave the upper 5 bits as the U and V processing values. Based on the Y, U, and V processing values created in this way, the compressed data is constructed in the format shown in FIG. 8 by the transmission data construction unit 37, and the compressed data is transmitted to the control device 3 by the communication unit 27. Is done.

  The compressed data in FIG. 8 will be briefly described. Each macroblock MBb of each frame F is grouped as the 1st to 30th block lines BL for each line. In each block line BL, following the header BLH and the 5-bit line number data BLN, the data of the macro blocks MBb from No. 1 to No. 40 included in the block line BL (for each macro block MBb) 550 bits are allocated).

  In the data of each macro block MBb, the processing values of Y, U, and V corresponding to each pixel in the macro block MBb are shown following the block number data MBN for 6 bits indicating the number of the macro block MBb. 8 are included in the order of description.

  Then, the transmission processing unit 15 of the control device 3 receives the compressed data sequentially sent from the camera unit 1 via the cable 7, and decompresses the compressed data in substantially the same manner as in the first embodiment. Then, the moving image data is reconstructed and given to the control unit 17, and the control unit 17 causes the display device 5 to display an image corresponding to the moving image data.

  Thereby, also in this embodiment, the effect substantially the same as the above-mentioned 1st Embodiment is acquired.

<Third Embodiment>
A video transmission system according to the third embodiment of the present invention will be described below. The video transmission system according to the present embodiment is substantially different from the video transmission system according to the first embodiment described above only in the image compression format, and the hardware configuration is the above-described FIG. 1 and FIG. The configuration is the same.

  In the present embodiment, as shown in FIG. 9, a 4 × 4 macro block MBc is set. The two subscripts (0 to 3, 0 to 3) attached to Y in FIG. 9 correspond to the matrix numbers of the pixels in the macroblock MBc, and the subscripts (0 to 0) attached to U and V. 3) corresponds to the identification number of each pixel group in the macroblock MBc.

  Then, as shown in FIG. 10, the Y processing unit 31 of the arithmetic processing unit 25 subordinates the value of Y corresponding to each pixel in each frame of the moving image data given via the memory 23 (8−N ) Bits (where N is a number of 6, 7 or 8) are rounded down or rounded off (in this case, rounded down), and the processing value of Y is created in order, leaving only the upper N bits. To 37. The U processing unit 33 and the V processing unit 35 round down or round off the lower 3 bits of the U value and V value corresponding to each pixel in each frame of the moving image data given through the memory 23 ( In this case, the processing value of U and the processing of V are sequentially created while leaving only the upper 5 bits, and sent to the transmission data configuration unit 37.

  The transmission data configuration unit 37 configures compressed data (see, for example, FIG. 11) obtained by compressing moving image data based on the Y, U, and V processing values created by the processing units 31, 33, and 35. Part 27 is given. The communication unit 27 transmits the compressed data to the control device 3.

  In this embodiment, the transmission data configuration unit 37 handles U and V processing values in substantially the same manner as in the first and second embodiments described above, but the Y processing value is processed as follows. The compressed image data is constructed.

  That is, for each macroblock MBc set in advance in each frame F, a minimum value (or maximum value) is extracted from the Y processing values corresponding to all the pixels in the macroblock MBc, and each macroblock MBc is extracted. For at least some of the pixels in the block MBc, instead of the Y processing value corresponding to at least some of the pixels, a difference value of the Y processing value with respect to the extracted minimum value (or maximum value); The compressed data is configured based on the minimum value (or the maximum value). For the Y component of each pixel in each macroblock MBc, which of the difference value or the Y processing value itself (absolute value) is used in the configuration of the compressed data depends on the difference value bit number D (the difference value is preset). D is determined based on any number of 2, 3, 4, and 5).

  Specifically, when the difference between the minimum value (or maximum value) and the processed value of Y is equal to or larger than the value obtained by raising 2 to the power of (D + 8−N), the absolute value is used for the compressed data, and the difference is If the value is less than the value obtained by raising 2 to the power of (D + 8−N), the difference value is used for the compressed data. Here, if the value of the difference value bit number D is small, there is a possibility that an absolute value must be used for the compressed data, but each Y processing value is close to the minimum value (or maximum value). In some cases, the compression ratio increases. Also, if the value of the difference value bit number D is large, the possibility that an absolute value must be used for the compressed data is reduced, which is efficient when the processing value of each Y is separated from the minimum value (or maximum value). Is good. In the present embodiment, whether the minimum value or the maximum value is used for the difference between the Y processing values is determined for each macroblock MBc, for example. Further, the value of the difference value bit number D is set in advance for each moving image data, for example.

  The compressed data in FIG. 11 will be briefly described. Each macro block MBc of each frame F is grouped as the 1st to 60th block lines BL for each line. In each block line BL, following the header BLH and the 6-bit line number data BLN, the data of the macroblocks MBc No. 1 to No. 80 included in the block line BL (data of each macroblock MBc) The length is variable).

  The data of each macroblock MBc includes block number data MBN for 7 bits indicating the number of the macroblock MBc, and maximum / minimum value data YMD for N bits indicating the minimum value (or maximum value) of the Y processing value. Subsequently, the storage method data SFD for 16 bits related to the storage method of the Y value corresponding to each pixel in the macro block MBc, and the processing values of U and V corresponding to the respective pixels in the macro block MBc. 40-bit UV processing value data UVD and Y processing value data YD (variable length data) for the Y value are included.

  FIGS. 12A to 12C are views showing the contents of the storage method data SFD, the UV processing value data UVD, and the Y processing value data YD in FIG. In the storage method data SFD, as shown in FIG. 12A, 16 settings corresponding to 1 bit corresponding to each of the 16 Y processing values corresponding to each pixel in the macro block MBc. Data SFDa is included. In each setting data SFDa, when the corresponding Y processing value is included in the compressed data as a difference value from the minimum value (or maximum value), a value “0” is set, and the corresponding Y processing value itself (absolute When the value is included in the compressed data, the value “1” is set. The correspondence between each setting data SFDa in the storage method data SFD and each Y processing value is as indicated by the Y suffix in FIG.

  As shown in FIG. 12B, the UV processing value data UVD includes U and V processing values corresponding to each image (each pixel group) in the macro block MBc in the order shown in FIG. ing.

  In the Y processing value data YD, as shown in FIG. 12C, the difference value from the minimum value (or the maximum value) of the Y processing values corresponding to each image in the macro block MBc or the Y processing value. The values themselves (absolute values) are included in the order shown in FIG. As to the processing value of each Y, which of the difference value and the absolute value is used to configure the compressed data is determined by the relationship between the difference value bit number D and the difference value as described above.

  FIGS. 13A to 13D show specific processing contents and processing procedures for the Y value corresponding to each pixel in the macroblock MBc. Here, the case where the value of Y corresponding to each pixel in the macroblock MBc is the value shown in FIG. For each Y value, if the number of bits left by truncation is N = 6 and the lower 2 bits are truncated, the Y processed value is obtained as shown in FIG. Note that the value in parentheses in FIG. 13B indicates an error value due to truncation. At this time, the minimum Y processing value is 8.

Subsequently, if the difference value bit number D is 2, the sum of the minimum value 8 and the (2 + 8−6) power value of 2 is 24. Therefore, when the processing value of Y is 24 or more, the absolute value Will be used for compressed data. For this reason, as shown in FIG. 13C, the processing values themselves (absolute values) are used as the compressed data for the processing values Y ₀₀ , Y ₀₁ , and Y ₀₂ , and the difference values are used for the other Y processing values. Are used for compressed data. Since each difference value in FIG. 13C is rounded down to the lower 2 bits, 0, 1, 2, 3 when the processing value of Y is 8, 12, 16, 20 Take each value. Then, the difference value or absolute value of Y obtained in this way is included in the compressed data and transmitted in the order indicated by 1, 2, 3,... In FIG.

  The storage method data SFD in this case has the contents as shown in FIG. 14A, and the Y processing value data YD has the contents as shown in FIG. Further, the maximum / minimum value data YMD has the minimum Y-processed value of 8 and the lower 2 bits are omitted, and therefore has the contents as shown in FIG.

In this example, the number of bits per pixel in the Y value is
(16 + 44 + 6) /16=4.125bit/pix <N = 6
This compression method can further reduce the data by about 31.25% for the Y component compared to the case of the first embodiment.

  In the transmission processing unit 15 of the control device 3, moving image data (values of Y, U, and V) is reconstructed based on the transmitted compressed data. The U and V component reconstruction processing is substantially the same as in the first embodiment, but the Y component reconstruction processing is different from that in the first embodiment. That is, among the Y component values (difference value, absolute value) included in the compressed data, the Y processing value itself is included for the absolute value, so that it is substantially the same as the reconstruction processing of the first embodiment. However, a special reconstruction process is required for the difference value. With respect to this difference value, based on the minimum value (or the maximum value) of the Y processing value of each macroblock MBc transmitted together with the difference value and the difference value, the corresponding Y processing value before the difference is re-transmitted. The Y value is reconfigured in substantially the same manner as in the first embodiment based on the reconfigured Y processing value. Whether each value of the transmitted Y component is a difference value or an absolute value is determined based on each corresponding setting data SFDa in the storage method data SFD.

  As described above, according to the present embodiment, substantially the same effects as those of the first embodiment described above can be obtained, and the difference between the processing values of Y corresponding to the respective pixels in the respective macroblocks MBc of the respective frames F can be obtained. When the number of value bits D is met, the compressed data is configured using a difference value from the minimum value (or the maximum value) of the Y processing value in the block MBc, thereby further improving the compression rate. it can.

<Fourth embodiment>
A video transmission system according to the fourth embodiment of the present invention will be described below. The video transmission system according to the present embodiment is substantially different from the video transmission system according to the third embodiment described above only in the image compression format, and the hardware configuration is the same as that in the third embodiment. Similarly, the configuration is the same as that shown in FIGS.

  In this embodiment, as shown in FIG. 15, an 8 × 8 macroblock MBd is set. The two subscripts (0 to 7, 0 to 7) attached to Y in FIG. 15 correspond to the identification numbers of the pixels in the macroblock MBd, and the subscripts (0 to 0) attached to U and V. 15) corresponds to the identification number of each pixel group in the macroblock MBd.

  Except for the difference in the size of the macroblock MBd, this is substantially the same as the processing contents of the third embodiment, and the Y processing unit 31 truncates the lower (8-N) bits for each Y value. N bits are left as Y processing values, and the U processing unit 33 and V processing unit 35 discard the lower 3 bits for each U and V value and leave the upper 5 bits as U and V processing values. Based on the Y, U, and V processing values created in this way, the compressed data is constructed in the format shown in FIG. 16 by the transmission data construction unit 37, and the compressed data is transmitted to the control device 3 by the communication unit 27. Is done.

  The compressed data in FIG. 16 will be briefly described. Each macroblock MBd of each frame F is grouped as the 1st to 30th block lines BL for each line. Each block line BL includes header BLH and 5-bit line number data BLN, followed by data (variable length data) of macro blocks MBd from No. 1 to No. 40 included in the block line BL. It is.

  The data of each macroblock MBd includes 6-bit block number data MBN indicating the number of the macroblock MBd and N-bit maximum / minimum value data YMD indicating the minimum value (or maximum value) of the Y processing value. Subsequently, the storage method data SFD for 64 bits relating to the storage method of the Y value corresponding to each pixel in the macroblock MBd, and the processing values of U and V corresponding to each pixel in the macroblock MBd 160-bit UV processing value data UVD and Y processing value data YD (variable length data) for the Y value are included.

  FIGS. 17A to 17C are diagrams showing the contents of the storage method data SFD, UV processing value data UVD, and Y processing value data YD in FIG. In the storage method data SFD, as shown in FIG. 17A, 64 settings corresponding to 1 bit corresponding to each of 64 Y processing values corresponding to each pixel in the macroblock MBd. Data SFDa is included. As shown in FIG. 17B, the UV processing value data UVD includes U and V processing values corresponding to the respective images in the macro block MBd in the order shown in FIG. In the Y processing value data YD, as shown in FIG. 17C, the difference value from the minimum value (or the maximum value) of the Y processing values corresponding to each image in the macro block MBd or the Y processing value. The values themselves (absolute values) are included in the order shown in FIG.

  Thereby, also in this embodiment, the effect substantially the same as the above-mentioned 3rd Embodiment is acquired.

<Fifth Embodiment>
A video transmission system according to the fifth embodiment of the present invention will be described below. The video transmission system according to the present embodiment is substantially different from the video transmission system according to the third embodiment described above. Which of the minimum value or the maximum value of the Y processing values is used to derive the Y difference value? Is automatically set for each macroblock MBe (see FIG. 18), and the hardware configuration is the same as that of FIGS. 1 and 2 as in the case of the third embodiment.

  In the present embodiment, as shown in FIG. 18, 4 × 4 macroblocks MBe are set. The setting contents of the macro block MBe and the contents of the processing value derivation process (the number of bits to be cut off) based on the Y, U, and V values corresponding to each pixel are the same as those in the third embodiment. Is omitted.

  In the present embodiment, in the compressed data configuration process by the transmission data configuration unit 37, whether the minimum value or the maximum value of the processing value of Y is used for the configuration of the compressed data in each macro block MBe is the minimum value or the maximum value. Is used for each macroblock MBe on the basis of whether the number of difference values to be applied to the difference value bit number D increases for the Y processing value corresponding to each pixel in the macroblock MBe. It has come to be decided. A specific example of this process will be described later.

  Correspondingly, as shown in FIG. 19, the data in each macro block MBe in the compressed data includes a processing value in the block MBe between the block number data MBN and the maximum / minimum value data YMD. One bit of maximum / minimum setting data MD indicating whether the minimum value or the maximum value is used as the Y processing value is added to the difference. For example, when the minimum value of the Y processing value is used for the difference, 0 is set as the maximum / minimum setting data MD, and when the maximum value of the Y processing value is used for the difference, the maximum / minimum setting data MD is 1 Is set.

  Here, FIGS. 20A to 20C are diagrams showing the contents of the storage method data SFD, UV processing value data UVD, and Y processing value data YD in FIG.

  FIGS. 21A to 21E show specific processing contents and processing procedures for the Y value corresponding to each pixel in the macro block MBe. Here, the case where the value of Y corresponding to each pixel in the macroblock MBe is the value shown in FIG. For each Y value, if the number of bits left by truncation is N = 6 and the lower 2 bits are truncated, a Y processing value is obtained as shown in FIG. Note that the value in parentheses in FIG. 21B indicates an error value due to truncation. At this time, the minimum processing value of Y is 8 and the maximum value is 132.

Subsequently, a method of determining the minimum value 8 or the maximum value 132 used for the difference will be described in the case where the difference value bit number D is 2. When the minimum value 8 is used for the difference, the sum of the minimum value 8 and the (2 + 8−6) power of 2 is 24, and when the Y processing value is 24 or more, the absolute value is used for the compressed data. As shown in FIG. 21C, the difference values can be used for the compressed data in three pixels Y ₃₁ , Y ₃₂ , and Y ₃₃ . On the other hand, when the maximum value 132 is used for the difference, the difference between the maximum value 132 and the (2 + 8-6) th power value of 2 is 116, and when the Y processing value is 116 or less, the absolute value is used for the compressed data. is therefore, as shown in FIG. 21 (d), the difference value into the compressed data is available is _{Y 00, Y 01, Y 03} , Y 10, Y 11, Y 12, 8 pixels Y _13, Y ₃₀ . Therefore, in this case, the maximum value 132 in which the number of usable pixels of the difference value is larger is used for the difference, and 1 is set in the maximum / minimum setting data MD. In addition, each absolute value in FIG.21 (c) and FIG.21 (d) displays the binary number which rounded down the lower 2 bits by the decimal number display. In addition, since each difference value in FIG. 21C is rounded down by the lower 2 bits, 0, 1, 2, 3 when the processing value of Y is 8, 12, 16, 20 Each difference value in FIG. 21 (d) is rounded down to the lower 2 bits, so that 0, 1, 2, when the processing value of Y is 132, 128, 124, 120 Each takes the value of 3.

  Then, the difference value or absolute value of Y obtained in this way is included in the compressed data and transmitted in the order indicated by 1, 2, 3,... In FIG.

  The storage method data SFD in this case has the contents as shown in FIG. 22A, and the Y processing value data YD has the contents as shown in FIG. Further, the maximum / minimum value data YMD has a content as shown in FIG. 22C because the maximum value of the processing value of Y is 132 and the lower 2 bits are omitted.

In this example, the number of bits per pixel in the Y value is
(16 + 64 + 6) /16=5.375bit/pix <N = 6
This compression method can further reduce the data by about 10.4% for the Y component compared to the case of the first embodiment.

  In the transmission processing unit 15 of the control device 3, moving image data (values of Y, U, and V) is reconstructed based on the transmitted compressed data. In this reconstruction process, the difference from the third embodiment is that the difference value of Y is based on the setting content (0 or 1) of the maximum / minimum setting data MD included in the data of each macroblock MBe. After determining whether the minimum value or the maximum value is used for each block MBe, the minimum value (or maximum value) of the Y processing value of each macroblock MBe transmitted together with the difference value and the difference between them. Based on the value, the corresponding Y processing value before the difference is reconstructed.

  As described above, in the present embodiment, substantially the same effects as those of the third embodiment described above can be obtained, and the compressed data configuration in each macroblock MBe can be selected from the minimum value or the maximum value of the Y processing values. Which one is used can be easily and accurately determined automatically, and the compression rate can be further improved.

<Modification>
As a modification of the first to fifth embodiments described above, the U and V processing values included in the compressed data may be set to once every two frames. That is, in this case, the U processing unit 33 and the V processing unit 35 set the U and V values corresponding to each pixel in each macroblock in the frame at a rate of one frame per two frames (by skipping one frame). Based on this, processing values for U and V are created. The transmission data configuration unit 37 includes U and V processing values in the compressed data at a rate of 1 frame per 2 frames (in other words, U and V processing at a rate of 1 frame per 2 frames). Configure the compressed data by omitting the value). Correspondingly, the transmission processing unit 15 of the control device 3 uses the U and V processing values to reconfigure the U and V values for the frames containing the U and V processing values. On the other hand, for frames that do not include U and V processing values, U and V processing values included in a frame received one time ahead (or one after) in time series The moving image data is reconstructed using the values of U and V obtained by reconstructing.

  For this reason, in this modified example, the compressed data is formed by omitting the U processing value and the V processing value at the rate of one frame out of two frames, so the data amounts of the U component and V component after compression are reduced. Further reduction can be achieved.

  As a further modification of the above modification, the U processing unit 33 and the V processing unit 35 alternately generate U and V processing values at a rate of one frame every two frames, that is, the U processing unit 33. And the processing value creation timing of the U and V of the V processing unit 35 are shifted by one frame, and in the frame in which the U processing unit 33 creates the U processing value, the V processing unit 35 pauses the creation of the V processing value and vice versa. In addition, the U processing unit 33 may pause the generation of the U processing value in the frame in which the V processing unit 35 generates the V processing value. In this case, the transmission data configuration unit 37 configures compressed data using the Y processing value and the U processing value other than the V processing value for the frame in which the U processing value is created by the U processing unit 33. For the frames for which the V processing value is created by the V processing unit 35, compressed data is configured using the Y processing value and the V processing value other than the U processing value. Then, the transmission processing unit 15 of the control device 3 uses the processing value for the processing value of either U or V included in the frame based on the transmitted data of each frame. While the value of either one of V or V is reconstructed, the processing value of either U or V that is not included in the frame is received one time ahead in the frame (or The moving image data is reconstructed using the values of U and V obtained by reconstructing using the processing value of either U or V included in the frame (received one after). Yes. In addition, what is necessary is just to provide the identification data area | region of 1 bit part in the header part of a frame for the identification of which U or V process value is contained in each frame.

  In this modification, in addition to the effect that the data amount of the U component and V component after compression can be further reduced, the data length of each frame after compression is averaged, so the size of the buffer for transmission and reception Can be easily optimized.

1 is a block diagram of a vehicle periphery monitoring device to which a moving image transmission system according to a first embodiment of the present invention is applied. FIG. 2 is a block diagram of a transmission processing unit in FIG. 1. It is explanatory drawing of a YUV420 format. It is a figure which shows the structure of the macroblock in 1st Embodiment. It is a figure which shows the truncation bit number in the value of Y, U, and V in 1st Embodiment. It is a figure which shows the structure of the compressed data in 1st Embodiment. It is a figure which shows the structure of the macroblock in 2nd Embodiment. It is a figure which shows the structure of the compression data in 2nd Embodiment. It is a figure which shows the structure of the macroblock in 3rd Embodiment. It is a figure which shows the truncation bit number in the value of Y, U, and V in 3rd Embodiment. It is a figure which shows the structure of the compressed data in 3rd Embodiment. 12A to 12C are diagrams showing the contents of the storage method data, UV process value data, and Y process value data in FIG. FIGS. 13A to 13D are diagrams showing specific processing contents and processing procedures for the Y value corresponding to each pixel in the macroblock of FIG. 14A to 14C are diagrams showing specific examples of the contents of the storage method data, Y processing value data, and maximum / minimum value data in FIG. It is a figure which shows the structure of the macroblock in 4th Embodiment. It is a figure which shows the structure of the compressed data in 4th Embodiment. FIGS. 17A to 17C are views showing the contents of the storage method data, UV process value data, and Y process value data in FIG. It is a figure which shows the structure of the macroblock in 5th Embodiment. It is a figure which shows the structure of the compression data in 5th Embodiment. 20A to 20C are views showing the contents of the storage method data, UV process value data, and Y process value data in FIG. FIGS. 21A to 21E are diagrams showing specific processing contents and processing procedures for the Y value corresponding to each pixel in the macroblock of FIG. FIGS. 22A to 22C are diagrams showing specific examples of the contents of the storage method data, Y process value data, and maximum / minimum value data in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Camera unit 3 Control apparatus 5 Display apparatus 11 Imaging part 13,15 Transmission process part 17 Control part 21 Pre-processing part 23 Memory 25 Arithmetic process part 27 Communication part 31 Y process part 33 U process part 35 V process part 37 Transmission data structure Part

Claims (14)

And figures of N _Y bits corresponding to the luminance signal Y, the luminance signal and the N _U bits of U numerical value corresponding to the difference between the red component, the luminance signal and the value of N _V bit V corresponding to the difference between the blue component A moving image compression apparatus for compressing moving image data represented using
For the Y value corresponding to each pixel in each frame of the input moving image data, the lower _MY bit portion (where _MY is an integer greater than or equal to 0 and less than _NY ) is rounded down or rounded off A first processing unit that creates a processing value of Y leaving only the upper (N _Y -M _Y ) bit portion of
The value of the U corresponding to each pixel in each frame of the input the moving image data, the lower M _U bit portion (where, M _U is integer of 1 or more and less than N _U) by truncating or rounding off the remainder A second processing unit that creates a processing value of U leaving only the upper (N _U -M _U ) bit portion of
For values of V corresponding to each pixel in each frame of the input the moving image data, the lower M _V bit portion (where the M _V 1 or an integer less than N _V) by truncating or rounding off the remainder A third processing unit that creates a processing value of V leaving only the upper (N _V −M _V ) bit portion of
The moving image data is compressed based on the Y processing value, the U processing value, and the V processing value created by the first processing unit, the second processing unit, and the third processing unit. A fourth processing unit constituting the compressed data,
A video compression apparatus comprising: The moving image compression apparatus according to claim 1,
Wherein M value of _U and the M _V is the is set larger than the value of M _Y, moving picture compression device. The moving image compression apparatus according to claim 1 or 2,
The fourth processing unit further includes:
For each pixel block having a preset vertical size of Ma pixels and horizontal size of Mb pixels in each frame, the minimum value or the maximum value among the Y processing values corresponding to all the pixels in the pixel block. And, for at least some of the pixels in each pixel block, instead of the Y processing value corresponding to the at least some pixels, the Y processing value for the minimum value or the maximum value A moving image compression apparatus that configures the compressed data based on the difference value of the data and the minimum value or the maximum value. The moving image compression apparatus according to claim 3,
The fourth processing unit further includes:
For the Y component of each pixel in each pixel block, whether the difference value or the processing value itself is used for the configuration of the compressed data is determined based on the difference value bit number set in advance for each pixel. A video compression apparatus that determines based on this. The moving image compression apparatus according to claim 4.
The fourth processing unit further includes:
Whether the minimum value or the maximum value is used for the configuration of the compressed data, and if the minimum value or the maximum value is adopted, the difference value corresponding to each pixel in each pixel block A moving image compression apparatus that determines for each pixel block based on whether the number of difference values adapted to the number of bits for difference value is larger. The moving image compression apparatus according to any one of claims 1 to 5,
The second processing unit and the third processing unit create the U processing value and the V processing value at a rate of one frame out of every two frames constituting the moving image,
For the frame in which the U processing value and the V processing value are created by the second processing unit and the third processing unit, the fourth processing unit performs the Y processing value and the U processing. For the frame in which the compressed data is configured based on the value and the V processing value, and the U processing value and the V processing value are not created by the first processing unit, the U processing value and the V A moving picture compression apparatus that constitutes the compressed data without using the processing value of The moving image compression apparatus according to any one of claims 1 to 5,
The second processing unit creates the processing value of the U at a rate of one frame out of every two frames constituting the moving image,
The third processing unit operates alternately with the second processing unit at a ratio of one frame to two of the frames constituting the moving image, and the second processing unit Create a processing value of V for a frame that does not create a processing value,
The fourth processing unit uses the Y processing value and the U processing value other than the V processing value for the frame in which the U processing value is created by the second processing unit. For a frame that constitutes compressed data and for which the V processing value is created by the third processing unit, the compressed data is processed using the Y processing value and the V processing value other than the U processing value. A video compression device. The moving picture compression apparatus according to any one of claims 1 to 7,
The moving image compression apparatus further comprising a fifth processing unit that transmits the compressed data configured by the fourth processing unit via a predetermined transmission path. A video transmission system for a vehicle,
The moving image compression apparatus according to claim 8,
An image expansion device that receives the compressed data transmitted by the moving image compression device via the transmission path, and reconstructs moving image data based on the received compressed data;
A video transmission system comprising: And figures of N _Y bits corresponding to the luminance signal Y, the luminance signal and the N _U bits of U numerical value corresponding to the difference between the red component, the luminance signal and the value of N _V bit V corresponding to the difference between the blue component A moving image compression method for compressing moving image data represented using
For the Y value corresponding to each pixel in each frame of the input moving image data, the lower _MY bit portion (where _MY is an integer greater than or equal to 0 and less than _NY ) is rounded down or rounded off A first processing step of creating a processing value for Y leaving only the upper (N _Y -M _Y ) bit portion of
The value of the U corresponding to each pixel in each frame of the input the moving image data, the lower M _U bit portion (where, M _U is integer of 1 or more and less than N _U) by truncating or rounding off the remainder A second processing step of creating a processing value of U leaving only the upper (N _U -M _U ) bit portion of
For values of V corresponding to each pixel in each frame of the input the moving image data, the lower M _V bit portion (where the M _V 1 or an integer less than N _V) by truncating or rounding off the remainder A third processing step of creating a processing value of V leaving only the upper (N _V -M _V ) bit portion of
The moving image data is compressed based on the Y processing value, the U processing value, and the V processing value created by the first processing step, the second processing step, and the third processing step. A fourth processing step constituting the compressed data,
A video compression method comprising: The moving image compression method according to claim 10,
Wherein M _U and a value of said M _V is the M _Y of is set larger than the value, video compression methods. The moving image compression method according to claim 10 or 11,
In the fourth processing step,
For each pixel block having a preset vertical size of Ma pixels and horizontal size of Mb pixels in each frame, the minimum value or the maximum value among the Y processing values corresponding to all the pixels in the pixel block. And, for at least some of the pixels in each pixel block, instead of the Y processing value corresponding to the at least some pixels, the Y processing value for the minimum value or the maximum value A moving image compression method that configures the compressed data based on a difference value between them and the minimum value or the maximum value. The moving image compression method according to claim 12,
In the fourth processing step,
For the Y component of each pixel in each pixel block, whether the difference value or the processing value itself is used for the configuration of the compressed data is determined based on the difference value bit number set in advance for each pixel. A video compression method that is determined based on this. The video compression method according to claim 13,
In the fourth processing step,
Whether the minimum value or the maximum value is used for the configuration of the compressed data, and if the minimum value or the maximum value is adopted, the difference value corresponding to each pixel in each pixel block A moving image compression method for determining each pixel block based on whether the number of the difference values adapted to the number of bits for the difference value is larger.

Images