# US 12,183,045 B2 · Mesh patch simplification

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- Number: US 12,183,045 B2
- Document ID: US12183045B2
- Status: Granted
- Kind: B2
- Application number: 17/987,841
- Filed: 2022-11-15
- Published: 2023-09-28
- Granted: 2024-12-31
- Earliest claimed: 2022-03-25
- Assignees: Sony Group Corporatiom; Sony Corporation of America
- Applicants: Sony Group Corporation; Sony Corporation of America
- Inventors: Danillo Graziosi; Alexandre Zaghetto; Ali Tabatabai
- Web page: https://patentgrep.com/patent/US12183045B2

## CPC

- G06T 9/001: {Model-based coding, e.g. wire frame}
- H04N 19/597: specially adapted for multi-view video sequence encoding
- G06T: IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- H04N: PICTORIAL COMMUNICATION, e.g. TELEVISION

## Abstract

Ways to simplify connectivity data for patches are described herein. The patches are generated considering the high-resolution mesh information. The connectivity data is simplified at the patch level, while the geometry image is still preserved. For the connectivity simplification, only triangles inside the patch are simplified. If the border is still preserved, the reconstruction in 3D will not suffer from artifacts. The high-resolution geometry image can be used to reverse the simplification and improve the connectivity at the decoder side. Three embodiments of patch mesh simplification are described: quadric error edge collapse, border distance edge collapse, and border triangles only.

## Claims

### Claim 1

A method programmed in a non-transitory memory of a device comprising:
generating a patch; and
performing two dimensional patch mesh simplification to generate a new face list and a new vertex list, wherein performing the two dimensional patch mesh simplification comprises a border triangles only implementation, wherein the border triangles only implementation comprises rotating a triangle so a first edge of the triangle is at a border.

### Claim 2 (depends on 1)

The method of claim 1 wherein performing the two dimensional patch mesh simplification comprises a quadric error edge collapse implementation.

### Claim 3 (depends on 2)

The method of claim 2 wherein the quadric error edge collapse implementation includes a half-edge collapse based on a quadric error metric.

### Claim 4 (depends on 1)

The method of claim 1 wherein performing the two dimensional patch mesh simplification comprises a border distance edge collapse implementation.

### Claim 5 (depends on 4)

The method of claim 4 wherein the border distance edge collapse implementation includes ordering a list of vertices according to a minimum distances to a border of the patch and collapsing a vertex with a neighboring vertex that is most distant to the border.

### Claim 6 (depends on 1)

The method of claim 1 further comprising implementing re-meshing at a decoder which includes marching cubes using border triangles and a decoded geometry video.

### Claim 7

An apparatus comprising:
a non-transitory memory for storing an application, the application for:
generating a patch; and
performing two dimensional patch mesh simplification to generate a new face list and a new vertex list, wherein performing the two dimensional patch mesh simplification comprises a border triangles only implementation, wherein the border triangles only implementation comprises rotating a triangle so a first edge of the triangle is at a border; and
a processor coupled to the memory, the processor configured for processing the application.

### Claim 8 (depends on 7)

The apparatus of claim 7 wherein performing the two dimensional patch mesh simplification comprises a quadric error edge collapse implementation.

### Claim 9 (depends on 8)

The apparatus of claim 8 wherein the quadric error edge collapse implementation includes a half-edge collapse based on a quadric error metric.

### Claim 10 (depends on 7)

The apparatus of claim 7 wherein performing the two dimensional patch mesh simplification comprises a border distance edge collapse implementation.

### Claim 11 (depends on 10)

The apparatus of claim 10 wherein the border distance edge collapse implementation includes ordering a list of vertices according to a minimum distances to a border of the patch and collapsing a vertex with a neighboring vertex that is most distant to the border.

### Claim 12 (depends on 7)

The apparatus of claim 7 wherein the application is further configured for implementing re-meshing at a decoder which includes marching cubes using border triangles and a decoded geometry video.

### Claim 13

A system comprising:
an encoder configured for:
generating a patch; and
performing two dimensional patch mesh simplification to generate a new face list and a new vertex list, wherein performing the two dimensional patch mesh simplification comprises a border triangles only implementation, wherein the border triangles only implementation comprises rotating a triangle so a first edge of the triangle is at a border; and
a decoder configured for:
implementing re-meshing which includes marching cubes using border triangles and a decoded geometry video.

### Claim 14 (depends on 13)

The system of claim 13 wherein performing the two dimensional patch mesh simplification comprises a quadric error edge collapse implementation.

### Claim 15 (depends on 14)

The system of claim 14 wherein the quadric error edge collapse implementation includes a half-edge collapse based on a quadric error metric.

### Claim 16 (depends on 13)

The system of claim 13 wherein performing the two dimensional patch mesh simplification comprises a border distance edge collapse implementation.

### Claim 17 (depends on 16)

The system of claim 16 wherein the border distance edge collapse implementation includes ordering a list of vertices according to a minimum distances to a border of the patch and collapsing a vertex with a neighboring vertex that is most distant to the border.