Checking overlapping-free property for patches in mesh compression

An apparatus for mesh processing, comprising processing circuitry configured to:

• receive, first UV coordinates associated with first vertices of a first patch and second UV coordinates associated with second vertices of a second patch, the first patch and the second patch being partitions from a three dimensional (3D) mesh, the 3D mesh representing a surface of an object with polygons and being partitioned into patches, the first patch comprising the first vertices that are mapped to first two dimensional (2D) vertices of a first 2D patch in a 2D map according to the first UV coordinates, the second patch comprising the second vertices that are mapped to second 2D vertices of a second 2D patch in the 2D map according to the second UV coordinates;
• determine a first region that encompasses the first 2D patch in the 2D map, the first region being larger than the first 2D patch;
• determine a second region that encompasses the second 2D patch in the 2D map, the second region being larger than the second 2D patch;
• determine whether the first region and the second region are overlapping free based on first corner coordinates of the first region and second corner coordinates of the second region;
• and
• determine whether the first 2D patch and the second 2D patch are overlapping free based on the first region and the second region, wherein:
• when the first 2D patch is an enlarged first 2D patch from a first initial 2D patch and the second 2D patch is an enlarged second 2D patch from a second initial 2D patch, the first 2D patch and the second 2D patch are determined to be overlapped when a square region corresponding to a corner pixel of the first initial 2D patch intersects a boundary edge of the second initial 2D patch.

A non-transitory computer-readable storage medium storing instructions which when executed by at least one processor cause the at least one processor to perform:

• receiving, first UV coordinates associated with first vertices of a first patch and second UV coordinates associated with second vertices of a second patch, the first patch and the second patch being partitions from a three dimensional (3D) mesh, the 3D mesh representing a surface of an object with polygons and being partitioned into patches, the first patch comprising the first vertices that are mapped to first two dimensional (2D) vertices of a first 2D patch in a 2D map according to the first UV coordinates, the second patch comprising the second vertices that are mapped to second 2D vertices of a second 2D patch in the 2D map according to the second UV coordinates;
• determining a first region that encompasses the first 2D patch in the 2D map, the first region being larger than the first 2D patch;
• determining a second region that encompasses the second 2D patch in the 2D map, the second region being larger than the second 2D patch;
• determining whether the first region and the second region are overlapping free based on first corner coordinates of the first region and second corner coordinates of the second region;
• and
• determining whether the first 2D patch and the second 2D patch are overlapping free based on the first region and the second region, wherein:
• when the first 2D patch is an enlarged first 2D patch from a first initial 2D patch and the second 2D patch is an enlarged second 2D patch from a second initial 2D patch, the first 2D patch and the second 2D patch are determined to be overlapped when a square region corresponding to a corner pixel of the first initial 2D patch intersects a boundary edge of the second initial 2D patch.