Methods of coding duplicate and isolated points for point cloud coding

1. A method for coding information of a point cloud, the method performed by at least one processor and comprising:

obtaining the point cloud including a set of points in a three-dimensional space;

determining whether a current node in the set of points is eligible to be coded in an isolated mode, wherein determining that the current node is eligible comprises:

determining that a current partition depth of the current node is smaller than a threshold, wherein the threshold is specified by a high-level syntax, and

determining that the current node has no siblings in an associated octree structure,

based on a determination that the current node is eligible to be coded in the isolated mode, coding the current node in isolation mode by:

setting a geometry isolation flag that indicates the current node has one or more isolated points coded in the isolated mode,

based on the geometry isolation flag indicating that the current node has the one or more isolated points coded in the isolated mode, determining whether the current node is eligible for a duplicate mode,

based on the current node being eligible for the duplicate mode, determining a number of duplicate points in the current node, and

determining an isolated position of the current node in the three-dimensional space, and

based on a determination that the current node is not isolated, coding the current node in a non-isolation mode.

2. The method of claim 1 , further comprising, based on a determination that the current node is a duplicate node, determining a duplicate number as the number of duplicate points.

3. The method of claim 2 , wherein the isolated position of the current node is determined after the duplicate number is determined.

4. The method of claim 1 , further comprising, in the non-isolation mode, coding the current node in the non-isolation mode, in which:

a duplicate number is determined for the current node based on a determination that the current node is a leaf node, or

occupancy information is determined based on a determination that the current node is not the leaf node.

5. The method of claim 4 , further comprising, in the non-isolation mode, determining whether the current node is the leaf node and terminating tree partition based on a determination that the current node is the leaf node.

6. The method of claim 5 , further comprising, based on a determination that the current node is not the leaf node, coding the current node to include occupancy information and inserting all occupied child nodes in a first-in-first-out list.

7. An apparatus for coding information of a point cloud, the apparatus comprising:

at least one memory storing computer program code; and

at least one processor configured to access the computer program code and operate as instructed by the computer program code, the computer program code including:

obtaining code configured to cause the at least one processor to obtain the point cloud including a set of points in a three-dimensional space;

isolation determining code configured to cause the at least one processor to determine whether a current node in the set of points is eligible to be coded in an isolated mode, wherein the isolation determining code comprises:

threshold determining code configured to cause the at least one processor to determine that a current partition depth of the current node is smaller than a threshold, wherein the threshold is specified by a high-level syntax, and

sibling determining code configured to cause the at least one processor to determine that the current node has no siblings in an associated octree structure,

encoding code configured to cause the at least one processor to, based on a determination that the current node is eligible to be coded in the isolated mode, code the current node in isolation mode by:

setting a geometry isolation flag that indicates the current node has one or more isolated points coded in the isolated mode,

based on the geometry isolation flag indicating that the current node has the one or more isolated points coded in the isolated mode, determining whether the current node is eligible for a duplicate mode,

based on the current node being eligible for the duplicate mode, determining a number of duplicate points in the current node, and

determining a position of the current node in the three-dimensional space; and

based on a determination that the current node is not isolated, coding the current node in a non-isolation mode.

8. The apparatus of claim 7 , wherein the encoding code is further configured to cause the at least one processor to, based on a determination that the current node is a duplicate node, determine a duplicate number as the number of duplicate points.

9. The apparatus of claim 7 , wherein, in the non-isolation mode, the encoding code is further configured to cause the at least one processor to code the current node in the non-isolation mode, in which:

a duplicate number is determined for the current node based on a determination that the current node is a leaf node, or

occupancy information is determined based on a determination that the current node is not the leaf node.

10. The apparatus of claim 9 , wherein, in the non-isolation mode, the encoding code is further configured to cause the at least one processor to determine whether the current node is the leaf node and terminate tree partition based on a determination that the current node is the leaf node.

11. The apparatus of claim 10 , wherein the encoding code is further configured to cause the at least one processor to code a duplicate number and terminating tree partition based on a determination that the current node is the leaf node.

12. The apparatus of claim 10 , wherein, based on a determination that the current node is not the leaf node, the encoding code is further configured to cause the at least one processor to code the current node to include occupancy information and inserting all occupied child nodes in a first-in-first-out list.

13. A non-transitory computer readable medium having stored thereon computer code that when executed by at least one processor can cause the processor to code information of a point cloud by:

obtaining the point cloud including a set of points in a three-dimensional space;

determining whether a current node in the set of points is eligible to be coded in an isolated mode, wherein determining that the current node is eligible comprises:

determining that a current partition depth of the current node is smaller than a threshold, wherein the threshold is specified by a high-level syntax, and

determining that the current node has no siblings in an associated octree structure,

based on a determination that the current node is eligible to be coded in the isolated mode, coding the current node in isolation mode by:

setting a geometry isolation flag that indicates the current node has one or more isolated points coded in the isolated mode,

based on the geometry isolation flag indicating that the current node has the one or more isolated points coded in the isolated mode, determining whether the current node is eligible for a duplicate mode,

based on the current node being eligible for the duplicate mode, determining a number of duplicate points in the current node, and

determining an isolated position of the current node in the three-dimensional space, and

based on a determination that the current node is not isolated, coding the current node in a non-isolation mode.

14. The non-transitory computer readable medium of claim 13 , further comprising:

determining a duplicate number as the number of duplicate points based on a determination that the current node is a duplicate node.

15. The non-transitory computer readable medium of claim 13 , wherein the isolated position of the current node is determined after the duplicate number is determined.