Adaptive partition coding
Although wedgelet-based partitioning seems to represent a better tradeoff between side information rate on the one hand and achievable variety in partitioning possibilities on the other hand, compared to contour partitioning, the ability to alleviate the constraints of the partitioning to the extent that the partitions have to be wedgelet partitions, enables applying relatively uncomplex statistical analysis onto overlaid spatially sampled texture information in order to derive a good predictor for the bi-segmentation in a depth/disparity map. Thus, in accordance with a first aspect it is exactly the increase of the freedom which alleviates the signaling overhead provided that co-located texture information in form of a picture is present. Another aspect pertains the possibility to save side information rate involved with signaling a respective coding mode supporting irregular partitioning.
1. A decoder for reconstructing a block of a depth map associated with a texture picture from a data stream, configured to:
determine a texture threshold based on a statistic of sample values of a reference block of the texture picture;
determine a contour partition of the reference block of the texture picture by comparing each sample of the reference block with the texture threshold;
predict a contour partition of the block of the depth map based on the contour partition of the reference block such that the block of the depth map is segmented into two portions; and
decode the block of the depth map based on the contour partition of the block of the depth map.
2. The decoder according to claim 1 , configured to, in determining the contour partition of the reference block, individually check values of the texture picture within the reference block at tiles of a two-dimensional subdivision of the reference block, as to whether the respective value is greater than or lower than a respective predetermined value, so that each of first and second portions of the reference block of the texture picture is a set of the tiles which together completely cover the reference block of the texture picture and are complementary to each other.
3. The decoder according to claim 2 , configured to, in determining the contour partition of the reference block, individually check values of the texture picture within the reference block at sample resolution so that each tile corresponds to a sample position of the reference block.
4. The decoder according to claim 1 , configured to, in determining a contour partition of the reference block, apply morphological hole filling and/or low-pass filtering onto a result of the comparing in order to acquire two portions of the reference block.
5. The decoder according to claim 1 , configured to, in determining the texture threshold, determine a measure for a central tendency of reconstructed sample values of the reference block of the texture picture, wherein the measure represents the texture threshold.
6. The decoder according to claim 1 , further configured to
determine a dispersion of value of samples within the reference block of the texture picture;
receive a coding option identifier from the data stream; and
use the coding option identifier as an index to perform the determining of the texture threshold, the determining of the contour partition of the reference block, the predicting of the contour partition of the block of the depth map, and the decoding operations in case of the dispersion exceeding a predetermined threshold.
7. The decoder according to claim 1 , wherein the statistic is a mean of the sample values of the reference block.
8. An encoder for encoding a block of a depth map associated with a texture picture into a data stream, configured to:
determine a texture threshold based on a statistic of sample values of a reference block of the texture picture;
determine a contour partition of the reference block of the texture picture by comparing each sample of the reference block with the texture threshold;
predict a contour partition of the block of the depth map based on the contour partition of the reference block such that the block of the depth map is segmented into two portions; and
encode, into the data stream, the block of the depth map based on the contour partition of the block of the depth map.
9. The encoder according to claim 8 , configured to, in determining the contour partition of the reference block, individually check values of the texture picture within the reference block at tiles of a two-dimensional subdivision of the reference block, as to whether the respective value is greater than or lower than a respective predetermined value, so that each of first and second portions of the reference block of the texture picture is a set of the tiles which together completely cover the reference block of the texture picture and are complementary to each other.
10. The encoder according to claim 9 , configured to, in determining the contour partition of the reference block, individually check values of the texture picture within the reference block at sample resolution so that each tile corresponds to a sample position of the reference block.
11. The encoder according to claim 8 , configured to, in determining the contour partition of the reference block, apply morphological hole filling and/or low-pass filtering onto a result of the comparing in order to acquire two portions of the reference block.
12. The encoder according to claim 8 , configured to, in determining the texture threshold, determine a measure for a central tendency of reconstructed sample values of the reference block of the texture picture, wherein the measure represents the texture threshold.
13. The encoder according to claim 8 , further configured to:
determine a dispersion of value of samples within the reference block of the texture picture; and
encode a coding option identifier into the data stream, wherein the coding option identifier is used as an index to perform the operations forming the determining of the texture threshold, the determining of the contour partition of the reference block, the predicting of the contour partition of the block of the depth map, and the decoding operations in case of the dispersion exceeding a predetermined threshold.
14. The encoder according to claim 8 , wherein the statistic is a mean of the sample values of the reference block.
15. A non-transitory computer-readable medium for storing data associated with a video, comprising:
a data stream stored in the non-transitory computer-readable medium, the data stream comprising encoded information of a reference block of a texture picture of the video and encoded information of a block of a depth map, which corresponds to the texture picture, of the video, wherein the block of the depth map is decoded using a plurality of operations including:
determining a texture threshold based on a statistic of sample values of a reference block of the texture picture;
determining a contour partition of the reference block of the texture picture by comparing each sample of the reference block with the texture threshold;
predicting a contour partition of the block of the depth map based on the contour partition of the reference block such that the block of the depth map is segmented into two portions; and
decoding the block of the depth map based on the contour partition of the block of the depth map.
16. The computer-readable medium according to claim 15 , wherein determining a contour partition of the reference block includes individually checking values of the texture picture within the reference block at tiles of a two-dimensional subdivision of the reference block, as to whether the respective value is greater than or lower than a respective predetermined value, so that each of first and second portions of the reference block of the texture picture is a set of the tiles which together completely cover the reference block of the texture picture and are complementary to each other.
17. The computer-readable medium according to claim 16 , wherein determining a contour partition of the reference block includes individually checking values of the texture picture within the reference block at sample resolution so that each tile corresponds to a sample position of the reference block.
18. The computer-readable medium according to claim 15 , wherein determining a contour partition of the reference block includes applying morphological hole filling and/or low-pass filtering onto a result of the comparing in order to acquire two portions of the reference block.
19. The computer-readable medium according to claim 13 , wherein determining the texture threshold includes determining a measure for a central tendency of reconstructed sample values of the reference block of the texture picture, wherein the measure represents the texture threshold.
20. The computer-readable medium according to claim 15 , wherein the statistic is a mean of the sample values of the reference block.