Fast recolor for video based point cloud coding

Patent metadata

Field	Value
Publication number	US-12101505-B2
Application number	US-202117500345-A
Country	US
Kind code	B2
Filing date	Oct 13, 2021
Priority date	Jun 4, 2021
Publication date	Sep 24, 2024
Grant date	Sep 24, 2024

Abstract

Methods and apparatuses of encoding a video stream using video point cloud coding include obtaining a source point cloud; obtaining a geometry-reconstructed point cloud, wherein the geometry-reconstructed point cloud is reconstructed using lossy coding; obtaining a target point included in the geometry-reconstructed point cloud; performing at least one of a forward K-dimensional (KD)-tree search to determine a first plurality of points of the source point cloud which are nearest neighbors to the target point, and a backward KD-tree search to determine a second plurality of points of the source point cloud for which the target point is a nearest neighbor; determining an average color value based on at least one of a first average color value of the first plurality of points and a second average color value of the second plurality of points; selecting a color value for the target point based on the average color value; and generating an encoded video stream based on the selected color value.

First claim

What is claimed is:

1. A method of encoding a video stream using video point cloud coding, the method being performed by at least one processor and comprising:
obtaining a source point cloud;
obtaining a geometry-reconstructed point cloud, wherein the geometry-reconstructed point cloud is reconstructed using lossy coding;
obtaining a target point included in the geometry-reconstructed point cloud;
performing a uni-directional search in which (i) a forward K-dimensional (KD)-tree search is performed to determine a first plurality of points of the source point cloud which are nearest neighbors to the target point and a backward KD-tree search is not performed, or (ii) the backward KD-tree search is performed to determine a second plurality of points of the source point cloud for which the target point is a nearest neighbor and the forward KD-tree search is not performed;
determining an average color value based on a first average color value of the first plurality of points in response to the forward KD-tree search being performed, and a second average color value of the second plurality of points in response to the backward KD-tree search being performed, the first average color value determined based on a Euclidian distance between two points including a first point in the first plurality of points and a second point in the geometry-reconstructed point cloud, the second average color value determined based on a Euclidian distance between two points including a first point in the second plurality of points and the second point in the geometry-reconstructed point cloud;
selecting a color value for the target point based on the average color value; and
generating an encoded video stream based on the selected color value.

2. The method of claim 1 , wherein the average color value is determined based on the second average color value without using the first average color value.

3. The method of claim 2 , wherein the two points are q and p r , wherein the second average color value is determined as follows:

Ψ
¯

2

=

∑

q
∈

Ψ
2

c
⁡
(
q
)

Δ
⁢

(

q
,

p
r

)

∑

q
∈

Ψ
2

1

Δ
⁢

(

q
,

p
r

)

,

where Ψ 2 represents the second plurality of points, Ψ 2 represents the second average color value, where c(q) represents a color of point q included in the second plurality of points, and where Δ(q,p r ) represents the Euclidian distance between q and p r .

4. The method of claim 1 , wherein the average color value is determined based on the first average color value without using the second average color value.

5. The method of claim 4 , wherein the two points are q and p r , wherein the first average color value is determined as follows:

Ψ
¯

1

=

∑

q
∈

Ψ
1

c
⁡
(
q
)

Δ
⁢

(

q
,

p
r

)

∑

q
∈

Ψ
1

1

Δ
⁢

(

q
,

p
r

)

,

where Ψ 1 represents the first plurality of points, Ψ 1 represents the first average color value, where c(q) represents a color of point q included in the first plurality of points, and where Δ(q,p r ) represents the Euclidian distance between q and p r .

6. The method of claim 1 , wherein the at least one of the first average color value and the second average color value is determine

Assignees

• Tencent America LLC

Inventors

• Zhang Xiang
• Gao Wen
• Liu Shan
• Feng Weiwei
• Jian Bing

Classifications

• H04N19/186

  the unit being a colour or a chrominance component · CPC title

• G06T9/00

  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

• H04N19/172

  the region being a picture, frame or field · CPC title

• H04N19/85

  using pre-processing or post-processing specially adapted for video compression · CPC title

• G06T9/40

  Tree coding, e.g. quadtree, octree · CPC title