Point cloud attribute entropy encoding method and device, and point cloud attribute entropy decoding method and device

Patent metadata

Field	Value
Publication number	US-12406398-B2
Application number	US-202218011397-A
Country	US
Kind code	B2
Filing date	Mar 11, 2022
Priority date	Mar 12, 2021
Publication date	Sep 2, 2025
Grant date	Sep 2, 2025

Abstract

The present invention provides a point cloud attribute entropy encoding method and device, and a point cloud attribute entropy decoding method and device. The encoding method comprises: if an overall encoding processing condition of point cloud attribute residual coefficients is satisfied, performing overall encoding processing on the point cloud attribute residual coefficients, and then ending the encoding; and if not, performing local one-by-one encoding processing on the point cloud attribute residual coefficients until the encoding is ended. The entropy decoding method comprises: if an overall decoding processing condition of the point cloud attribute residual coefficients is satisfied, performing overall decoding processing on the point cloud attribute residual coefficients, and then ending the decoding; and if not, performing local one-by-one decoding processing on the point cloud attribute residual coefficients until the decoding is ended. The present invention better utilizes redundant information in a point cloud and improves compression performance.

First claim

The invention claimed is:

1. A point cloud attribute entropy encoding method, comprising:
for attribute residual coefficients A 1 , A 2 , . . . , A M of a current point, M being an integer greater than 1, determining whether the M attribute residual coefficients A 1 , A 2 , . . . , A M are equal to 0 at the same time;
if the M attribute residual coefficients A 1 , A 2 , . . . , A M are equal to 0 at the same time, the encoding of the attribute residual coefficients of the current point is ended;
if the M attribute residual coefficients A 1 , A 2 , . . . , A M are not equal to 0 at the same time, the encoding a flag bit F k by utilizing contexts to represent whether A k is equal to 0, 0<k<=M;
determining whether A k is equal to 0;
if A k is not equal to 0, adaptively selecting contexts to encode uncoded residual coefficients of the current point by utilizing encoded attribute residual coefficients of the current point;
ending the encoding of the attribute residual coefficients of the current point;
if A k is equal to 0, encoding a flag bit F j by utilizing contexts to represent whether A j is equal to 0, 0<j<=M, and j is not equal to k;
determining whether A j is equal to 0;
if A j is equal to 0, adaptively selecting contexts to encode the uncoded attribute residual coefficients other than A j and A k of the current point by utilizing the encoded attribute residual coefficients of the current point;
ending the encoding of the attribute residual coefficients of the current point;
if A j is not equal to 0, adaptively selecting contexts to encode the uncoded attribute residual coefficients other than A k of the current point by utilizing the encoded attribute residual coefficients of the current point; and
ending the encoding of the attribute residual coefficients of the current point.

2. The point cloud attribute entropy encoding method of claim 1 , wherein
if the attribute residual coefficient A 1 or A 2 , . . . , or A M of the current point is equal to 0, the attribute residual coefficient is taken as an entropy encoding value, and the entropy encoding value is encoded;
when the encoded attribute residual coefficient A 1 or A 2 , . . . , or A M is not equal to 0 and no flag bits are provided, an absolute value of the attribute residual coefficient is taken as an entropy encoding value, and the entropy encoding value and a positive or negative sign bit of the corresponding attribute residual value are encoded; and
when the encoded attribute residual coefficient A 1 or A 2 , . . . , or A M is not equal to 0 and flag bits are provided, a difference obtained by subtracting 1 from the absolute value of the attribute residual coefficient is taken as an entropy encoding value, and the entropy encoding value and a positive or negative sign bit of the corresponding attribute residual value are encoded.

3. The point cloud attribute entropy encoding method of claim 2 , wherein the step of encoding the entropy encoding value specifically comprises:
encoding a flag bit by utilizing contexts to represent whether the entropy encoding value is equal to 0;
if the entropy encoding value is not equal to 0, encoding a flag bit by utilizing contexts to represent whether the entropy encoding value is equal to 1;
if the entropy encoding value is not equal to 1, encoding a flag bit by utilizing contexts to represent whether the entropy encoding value is equal to 2;
performing the operation successively until a flag bit is encoded by utilizing contexts to represent whether the entropy encoding value is equal to n, n is greater than 0; and
if the entropy encoding value is not equal to n, encoding a difference obtained by subtracting n+1 from this value.

4. The point cloud attribute entropy encoding method of claim 1 , wherein the step of adaptively selecting contexts to encode uncoded residual coefficients of the current point by utilizing encoded attribute residual coefficients of the current point specifically comprises:
for an encoded attribute residual coefficient A t of the current point, setting H flag bits b t0 , b t1 , . . . , bt (H-1 ), wherein b th represents whether A t is equal to h, and h=0, 1, . . . , H−1; and
for r encoded attribute residual coefficients of the current point, encoding the uncoded residual coefficients of the current point by taking a number of r/H flag bits as contexts.

5. A point cloud attribute entropy decoding method, comprising:
a code stream being decoded;
for attribute residual coefficients A 1 , A 2 , . . . , A M of the current point, M being an integer greater than 1, determining whether the M attribute residual coefficients A 1 , A 2 , . . . , A M are equal to 0 at a same time;
if the M attribute residual coefficients A 1 , A 2 , . . . , A M are equal to 0 at the tame time, the decoding of the attribute residual coefficients of the current point is ended;
if the M attribute residual coefficients A 1 , A 2 , . . . , A M are not equal to 0 at the same time, decoding a flag bit F k by utilizing contexts to represent whether A k is equal to 0, 0<k<=M;
determining whether A k is equal to 0;
if A k is not equal to 0, adaptively selecting contexts to decode undecoded residual coefficients of the current point by utilizing decoded attribute residual coefficients of the current point;
ending the decoding of the attribute residual coefficients of the current point;
if A k is equal to 0, decoding a flag bit F j by utilizing contexts to represent whether A j is equal to 0, 0<j<=M, and j is not equal to k;
determining whether A j is equal to 0;
if A j is equal to 0, adaptively selecting contexts to decode the undecoded attribute residual coefficients other than A j and A k of the current point by utilizing the decoded attribute residual coefficients of the current point;
ending the decoding of the attribute residual coefficients of the current point;
if A j is not equal to 0, adaptively selecting contexts to decode the undecoded attribute residual coefficients other than A k of the current point by utilizing the decoded attribute residual coefficients of the current point;
ending the encoding of the attribute residual coefficients of the current point.

6. The point cloud attribute entropy decoding method of claim 5 , wherein
decoding is performed to obtain an entropy decoding value, and when the entropy decoding value is equal to 0, the entropy decoding value is taken as the attribute residual coefficient A 1 or A 2 , . . . , or A M ;
when the entropy decoding value is not equal to 0 and no flag bits are provided, the entropy decoding value is taken as an absolute value of the attribute residual coefficient A 1 or A 2 , . . . , or A M , and decoding is performed to obtain a positive or negative sign bit of the attribute residual coefficient A 1 or A 2 , . . . , or A M ; and
when the entropy decoding value is not equal to 0 and flag bits are provided, a sum obtained by adding 1 to the entropy decoding value is taken as the absolute value of the attribute residual coefficient A 1 or A 2 , . . . , or A M , and decoding is preformed to obtain a positive or negative sign bit of the attribute residual coefficient A 1 or A 2 , . . . , or A M .

7. The point cloud attribute entropy decoding method of claim 6 , wherein the step that decoding is performed to obtain an entropy decoding value specifically comprises:
decoding a flag bit by utilizing contexts to represent whether the entropy decoding value is equal to 0;
if the entropy decoding value is not equal to 0, decoding a flag bit by utilizing contexts to represent whether the entropy decoding value is equal to 1;
if the entropy decoding value is not equal to 1, decoding a flag bit by utilizing contexts to represent whether the entropy

Assignees

• Univ Peking Shenzhen Graduate School

Inventors

• Li Ge
• Ma Chuang
• Wang Jing
• Shao Yiting

Classifications

• G06T9/005

  Statistical coding, e.g. Huffman, run length coding · CPC title

• H04N13/161

  Encoding, multiplexing or demultiplexing different image signal components (for multi-view video sequence encoding H04N19/597) · CPC title

• G06T9/00 Primary

  Image coding (bandwidth or redundancy reduction for static pictures H04N1/41; coding or decoding of static colour picture signals H04N1/64; methods or arrangements for coding, decoding, compressing or decompressing digital video signals H04N19/00) · CPC title

• G06T9/001 Primary

  Model-based coding, e.g. wire frame · CPC title

• H04N19/13 Primary

  Adaptive entropy coding, e.g. adaptive variable length coding [AVLC] or context adaptive binary arithmetic coding [CABAC] · CPC title