An image coding method according to one aspect includes dividing an input image into processing target block(s), determining a mode of an intra-picture prediction of the processing target block in units of the divided processing target block(s), holding the prediction mode into a holding unit, estimating the intra prediction mode of the processing target block, comparing the result of the prediction mode determination and the result of the prediction mode estimation to determine whether they match each other, coding the result of the comparison, and further, when the result of the comparison indicates a mismatch, coding the result of the prediction mode determination. An intra prediction mode of one or more predetermined processing units surrounding the processing target block from the holding unit is acquired and compared, and the coding is controlled based on the result of the mode comparison.
Legal claims defining the scope of protection, as filed with the USPTO.
1. An image coding apparatus comprising: a division unit configured to divide an input image into a processing target block; a prediction mode determination unit configured, in units of the processing target block divided by the division unit, to determine a mode of an intra-picture prediction of the processing target block; a holding unit configured to hold the intra prediction mode determined by the prediction mode determination unit; a prediction mode estimation unit configured to estimate the intra prediction mode of the processing target block based on an intra prediction mode of a surrounding block around the processing target block, which is held by the holding unit; a determination unit configured to determine whether the result of the prediction mode determination unit and the result of the prediction mode estimation unit match each other; a coding unit configured to code the result of the determination unit, and further, when the result of the determination unit indicates a mismatch, to code the result of the prediction mode determination unit; a mode comparison unit configured to acquire an intra prediction mode of one or more predetermined block surrounding the processing target block from the holding unit to compare the mode; and a control unit configured to control the coding unit based on the result of the mode comparison unit.
2. The image coding apparatus according to claim 1 , wherein the mode comparison unit determines whether all of the intra prediction mode of the one or more predetermined block surrounding the processing target block match or do not match, and wherein the control unit controls the coding unit based on the result of the determination of the mode comparison unit.
3. The image coding apparatus according to claim 2 , wherein, in a case where the result of the determination of the mode comparison unit indicates a match, the control unit controls the coding unit so as not to code the result of the determination unit for a block to be processed last in processing of the one or more predetermined block according to a predetermined order.
4. The image coding apparatus according to claim 3 , wherein, in a case where the result of the determination of the mode comparison unit indicates a mismatch, the control unit controls the coding unit so as to code the result of the determination unit for the block to be processed last in the processing of the one or more predetermined block according to the predetermined order.
5. An image decoding apparatus comprising: a holding unit configured to hold a decoded intra prediction mode of each block; a prediction mode estimation unit configured to acquire an intra prediction mode of one or more predetermined block surrounding a processing target block from the holding unit to estimate an intra prediction mode of the processing target block; an intra prediction decoding unit configured to decode a mode estimation matching code, which indicates whether the intra prediction mode of the processing target block and the result of the prediction mode estimation unit match each other at the time of coding, and decode the intra prediction mode in a case where the result of the decoding indicates a mismatch; a mode comparison unit configured to acquire the intra prediction mode of the one or more predetermined block surrounding the processing target block from the holding unit to compare the mode; a block determination unit configured to determine whether the processing target block is a final processing block in a block; and a control unit configured to control the intra prediction decoding unit based on the result of the mode comparison unit and the result of the block determination unit.
6. An image coding method comprising: dividing an input image into processing target block(s); determining a mode of an intra-picture prediction of the processing target block in units of the divided processing target block(s); holding the prediction mode into a holding unit; estimating the intra prediction mode of the processing target block based on the held intra prediction mode of a surrounding block around the processing target block; comparing the result of the prediction mode determination and the result of the prediction mode estimation to determine whether they match each other; coding the result of the comparison, and further, when the result of the comparison indicates a mismatch, coding the result of the prediction mode determination; and acquiring and comparing an intra prediction mode of one or more predetermined block surrounding the processing target block from the holding unit, wherein the coding is controlled based on the result of the mode comparison.
7. The image coding method according to claim 6 , wherein the mode comparing includes determining whether all of the intra prediction mode of the one or more predetermined block surrounding the processing target block match or do not match, and wherein the controlling includes controlling the coding based on the result of the determination of the mode comparison.
8. The image coding method according to claim 7 , wherein, in a case where the result of the determining the mode comparison indicates a match, the controlling includes controlling the coding so as not to code the result of the comparing for a block to be processed last in processing of the one or more predetermined block according to a predetermined order.
9. The image coding method according to claim 8 , wherein, in a case where the result of the determination of the mode comparing indicates a mismatch, the controlling includes controlling the coding so as to code the result of the comparing for the block to be processed last in the processing of the one or more predetermined block according to the predetermined order.
10. An image decoding method comprising: holding a decoded intra prediction mode of each block into a holding unit; acquiring an intra prediction mode of one or more predetermined block surrounding a processing target block from the holding unit to estimate an intra prediction mode of the processing target block; decoding a mode estimation matching code, which indicates whether the intra prediction mode of the processing target block and the result of the prediction mode estimation match each other at the time of coding, and decoding the intra prediction mode in a case where the result of the decoding indicates a mismatch; acquiring the intra prediction mode of the one or more predetermined block surrounding the processing target block from the holding to compare the mode; determining whether the processing target block is a final processing block in a block; and controlling the intra prediction decoding based on the result of the mode comparing and the result of the block determining.
11. Non-transitory storage medium storing an image coding program to perform operations comprising: dividing an input image into processing target block(s); determining a mode of an intra-picture prediction of the processing target block in units of the processing target block(s) divided by the dividing; holding the prediction mode into a holding unit; estimating the intra prediction mode of the processing target block based on the intra prediction mode of a surrounding block around the processing target block held in the holding unit; comparing the result of the prediction mode determining and the result of the prediction mode estimating to determine whether they match each other; coding the result of the comparing, and further, when the result of the comparing indicates a mismatch, coding the result of the prediction mode determining; acquiring an intra prediction mode of one or more predetermined block surrounding the processing target block from the holding unit to compare the mode; and controlling the coding based on the result of the mode comparing.
12. Non-transitory storage medium storing an image decoding program to perform operations comprising: holding a decoded intra prediction mode of each block into a holding unit; acquiring an intra prediction mode of one or more predetermined block surrounding a processing target block from the holding unit to estimate an intra prediction mode of the processing target block as prediction mode estimation; decoding a mode estimation matching code, which indicates whether the intra prediction mode of the processing target block and the result of the prediction mode estimation match each other at the time of coding, and decoding the intra prediction mode in a case where the result of the decoding indicates a mismatch; acquiring the intra prediction mode of the one or more predetermined block surrounding the processing target block from the holding to compare the mode; determining whether the processing target block is a final processing block in a block; and controlling the intra prediction decoding based on the result of the mode comparing and the result of the block determining.
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January 12, 2012
February 23, 2016
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