Region-adaptive hierarchical transform and entropy coding for point cloud compression, and corresponding decompression

One or more computer-readable media storing computer-executable instructions for causing a computer system, when programmed thereby, to perform operations comprising:

• receiving encoded data as part of a bitstream;
• decoding the encoded data to reconstruct point cloud data, the point cloud data comprising multiple points in three-dimensional (“3D”) space, each of the multiple points being associated with an indicator of whether the point is occupied and, if the point is occupied, an attribute of the occupied point, wherein the decoding the encoded data includes:
• applying an inverse region-adaptive hierarchical transform (“RAHT) to transform coefficients for attributes of occupied points among the multiple points, wherein the applying the inverse RAHT includes, at a given level of a hierarchy for the point cloud data, for each given group of one or more groups of points at the given level:
• inverse transforming one or more values for the given group, thereby producing any attributes of occupied points of the given group, wherein the one or more values include any of the transform coefficients that are associated with the given group at the given level;
• and
• if the given level is not top level of the hierarchy, reserving the any attributes of occupied points of the given group, for use as attributes at a next higher level than the given level in the hierarchy, in successive application of the inverse RAHT at the next higher level;
• and
• storing the reconstructed point cloud data.

In a computer system, a method comprising:

• receiving encoded data as part of a bitstream;
• and
• decoding the encoded data to reconstruct point cloud data, the point cloud data comprising multiple points in three-dimensional (“3D”) space, each of the multiple points being associated with an indicator of whether the point is occupied and, if the point is occupied, an attribute of the occupied point, wherein the attribute is selected from the group consisting of:
• a sample value defining, at least in part, a color associated with the occupied point;
• an opacity value defining, at least in part, an opacity associated with the occupied point;
• a specularity value defining, at least in part, a specularity coefficient associated with the occupied point;
• a surface normal value defining, at least in part, direction of a flat surface associated with the occupied point;
• a motion vector defining, at least in part, motion associated with the occupied point;
• and
• a light field defining, at least in part, a set of light rays passing through or reflected from the occupied point;
• and
• wherein the decoding the encoded data includes:
• applying an inverse region-adaptive hierarchical transform (“RAHT”) to transform coefficients for attributes of occupied points among the multiple points;
• and
• storing the reconstructed point cloud data.

In a computer system, a method comprising:

• receiving point cloud data comprising multiple points in three-dimensional (“3D”) space, each of the multiple points being associated with an indicator of whether the point is occupied and, if the point is occupied, an attribute of the occupied point, wherein the attribute is selected from the group consisting of:
• a sample value defining, at least in part, a color associated with the occupied point;
• an opacity value defining, at least in part, an opacity associated with the occupied point;
• a specularity value defining, at least in part, a specularity coefficient associated with the occupied point;
• a surface normal value defining, at least in part, direction of a flat surface associated with the occupied point;
• a motion vector defining, at least in part, motion associated with the occupied point;
• and
• a light field defining, at least in part, a set of light rays passing through or reflected from the occupied point;
• encoding the point cloud data, thereby producing encoded data, wherein the encoding includes:
• applying a region-adaptive hierarchical transform (“RAHT”) to attributes of occupied points among the multiple points, thereby producing transform coefficients;
• and
• outputting the encoded data as part of a bitstream.