METHODS AND APPARATUSES FOR CODING AND DECODING DEPTH MAP

• US 20180302649A1
• Filed: 06/19/2018
• Published: 10/18/2018
• Est. Priority Date: 01/10/2013
• Status: Active Grant

• Current Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Original Assignee: Huawei Technologies Co., Ltd. (Huawei Investment & Holding Co., Ltd.)
• Inventors: ZHENG, Xiaozhen
• Granted Patent: US 10,455,251 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 19/103 Selection of coding mode or of prediction mode
• CPC Class Codes: H04N 19/105 Selection of the reference unit for prediction within a chosen coding or prediction mode, e.g. adaptive choice of position and number of pixels used for prediction
• CPC Class Codes: H04N 19/139 Analysis of motion vectors, e.g. their magnitude, direction, variance or reliability
• CPC Class Codes: H04N 19/159 Prediction type, e.g. intra-frame, inter-frame or bidirectional frame prediction
• CPC Class Codes: H04N 19/176 the region being a block, e.g. a macroblock
• CPC Class Codes: H04N 19/59 involving spatial sub-sampling or interpolation, e.g. alteration of picture size or resolution
• CPC Class Codes: H04N 19/593 involving spatial prediction techniques
• CPC Class Codes: H04N 19/597 specially adapted for multi-view video sequence encoding

Abstract

Embodiments of the present invention provide methods and apparatuses for coding and decoding a depth map. The coding method includes: obtaining prediction data corresponding to a current image block of the depth map, obtaining a predicted pixel value from the prediction data according to a preset step, and calculating a first average value of the prediction data according to the predicted pixel value, where the preset step is a positive integer except 1; obtaining a residual of the current image block according to the first average value of the prediction data and a pixel value of a pixel of the current image block; and coding the residual of the current image block. In this way, coding and decoding efficiency can be improved.

Claims

1. A method for coding a depth map provided by one or more processing modules and a coding module executing instructions stored in a non-transitory, computer-readable storage medium so as to configure the modules to provide the method of:

obtaining, by a first processing module, prediction data of a current image block of the depth map;

obtaining, by the first processing module, a predicted pixel value from the prediction data according to a preset process;

obtaining, by the first processing module, a first average value of the prediction data according to the predicted pixel value, wherein the preset process is determined based on a size of the current image block, and wherein different preset processes are determined for different sizes of the current image block so that a number of the obtained predicted pixel values for each of the different sizes of the current image block is the same;

obtaining, by a second processing module, a residual of the current image block according to the first average value of the prediction data and a pixel value of a pixel of the current image block; and

coding, by a coding module, the residual of the current image block.

2. The method according to claim 1, wherein obtaining the residual of the current image block comprises one selected from the group consisting of:

(a) performing a difference operation between the pixel value of the pixel of the current image block and the first average value of the prediction data of the current image block to obtain the residual of the current image block; and

(b) determining a second average value of the data of the current image block according to the predicted pixel value of the data of the current image block, and performing a difference operation between the second average value of the data of the current image block and the first average value of reference data of the current image block to obtain the residual of the current image block.

3. The method according to claim 1, further comprising coding a value of the preset process.

4. The method according to claim 1, wherein the preset process is used to identify an interval between position coordinates of the prediction data.

5. The method according to claim 1, wherein coding the residual of the current image block comprises:

mapping the residual to a mapping value of the residual, wherein a number of bits that represent the mapping value of the residual is less than a number of bits that represent the residual; and

coding the mapping value of the residual.

6. The method according to claim 1, wherein before obtaining the predicted pixel value from the prediction data according to the preset process, the method further comprises:

determining, according to an intra-frame prediction mode of the current image block, whether the intra-frame prediction mode belongs to a preset intra-frame prediction mode set; and

if it is determined that the intra-frame prediction mode belongs to the preset intra-frame prediction mode set, determining the predicted pixel value from the prediction data according to the preset step.

7. The method according to claim 6, wherein the intra-frame prediction mode set comprises at least one of the following intra-frame prediction modes:

a direct current (DC) mode;

a Planar mode;

an explicit Wedgelet mode; and

an intra-predicted Wedgelet partitioning mode.

8. A method for decoding a depth map provided by processing and decoding modules executing instructions stored in a non-transitory, computer-readable storage medium so as to configure the modules to provide the method of:

obtaining, by a processing module, prediction data of a current image block of the depth map;

obtaining, by the processing module, a predicted pixel value from the prediction data according to a preset process;

obtaining, by the processing module, a first average value of the prediction data according to the predicted pixel value, wherein the preset process is determined based on a size of the current image block, and wherein different preset processes are determined for different sizes of the current image block so that a number of the obtained predicted pixel values for each of the different sizes of the current image block is the same;

obtaining, by a decoding module, a residual of the current image block; and

obtaining, by the decoding module, a pixel value of a pixel of the current image block according to the first average value of the prediction data and the residual of the current image block.

9. The method according to claim 8, wherein obtaining the pixel value of the pixel of the current image block according to the first average value of the prediction data and the residual of the current image block comprises one selected from the group consisting of:

(a) adding the first average value of the prediction data of the current image block and the residual of the current image block to obtain the pixel value of the pixel of the current image block; and

(b) adding the first average value of the prediction data of the current image block and the residual to obtain an average pixel value of the current image block, and using the average pixel value of the current image block as the pixel value of the pixel of the current image block.

10. The method according to claim 9, further comprising parsing a bitstream to obtain a value that identifies the preset process.

11. The method according to claim 9, wherein the preset process is used to identify an interval between position coordinates of the prediction data.

12. The method according to claim 9, wherein obtaining the residual of the current image block comprises:

performing decoding processing on a coding result of the current image block to obtain a mapping value of the residual of the current image block; and

mapping the mapping value of the residual to the residual, and using the residual as the residual of the current image block, wherein the number of bits that represent the mapping value of the residual is less than the number of bits that represent the residual.

13. The method according to claim 9, wherein before obtaining the predicted pixel value from the prediction data according to the preset process, the method further comprises:

determining, according to an intra-frame prediction mode of the current image block, whether the intra-frame prediction mode belongs to a preset intra-frame prediction mode set; and

if the intra-frame prediction mode belongs to the preset intra-frame prediction mode set, determining the predicted pixel value from the prediction data according to the preset process.

14. The method according to claim 13, wherein the intra-frame prediction mode set comprises at least one of the following intra-frame prediction modes:

a direct current (DC) mode;

a Planar mode;

an explicit Wedgelet mode; and

an intra-predicted Wedgelet partitioning mode.

15. An apparatus for decoding a depth map comprising a processor and a memory with stored instructions which when executed by the processor cause the processor to:

obtain prediction data of a current image block of the depth map;

obtain a predicted pixel value from the prediction data according to a preset process;

obtain a first average value of the prediction data according to the predicted pixel value, wherein the preset process is determined based on a size of the current image block, and wherein different preset processes are determined for different sizes of the current image block so that a number of the obtained predicted pixel values for the different sizes of the current image block are the same; and

obtain a residual of the current image block, and obtain a pixel value of a pixel of the current image block according to the first average value of the prediction data and the residual of the current image block.

16. The apparatus according to claim 15, wherein the processor is further configured to perform one selected from the group consisting of:

(a) adding the first average value of the prediction data of the current image block and the residual of the current image block to obtain the pixel value of the pixel of the current image block; and

(b) adding the first average value of the prediction data of the current image block and the residual to obtain an average pixel value of the current image block, and use the average pixel value of the current image block as the pixel value of the pixel of the current image block.

17. The apparatus according to claim 15, wherein the processor is further configured to parse a bitstream to obtain a value that identifies the preset process.

18. The apparatus according to claim 15, wherein the preset process is used to identify an interval between position coordinates of the prediction data.

19. The apparatus according to claim 15, wherein the processor is further configured to perform decoding processing on a coding result of the current image block to obtain a mapping value of the residual of the current image block, map the mapping value of the residual to the residual of the current image block, and use the mapping value of the residual as the residual of the current image block, wherein a number of bits that represent the mapping value of the residual is less than a number of bits that represent the residual.

20. The apparatus according to claim 19, wherein the processor is further configured to:

determine, according to an intra-frame prediction mode of the current image block, whether the intra-frame prediction mode belongs to a preset intra-frame prediction mode set; and

when the intra-frame prediction mode belongs to the preset intra-frame prediction mode set, determine the predicted pixel value from the prediction data according to the preset process.