Vextex correction method and apparatus for rotated three-dimensional (3D) components

摘要

A 3D model can be modeled using pattern-instance representation, wherein an instance component may be represented as transformation (for example, rotation, translation, and scaling) of a pattern. Quantization errors may be introduced when encoding rotation information, causing different vertex coordinate errors at different vertices of an instance. To efficiently compensate the vertex coordinate errors, an upper bound can be estimated for the vertex coordinate error of a vertex. Based on the upper bound, the codec decides whether the vertex coordinate error of the vertex needs to be compensated, and decides a quantization parameter for compensating the vertex coordinate error if compensation is needed. The upper bound can be estimated at both the encoder and decoder, and thus, no explicit signaling is needed to indicate whether vertex coordinate error compensation is used or to indicate the quantization parameter for the vertex coordinate error.

主权项

1. A method for generating or decoding a bitstream representing a 3D model, comprising:
accessing a reconstructed instance corresponding to an instance associated with a pattern, the pattern representative of a plurality of repetitive structures in the 3D model, and the instance being one of the plurality of repetitive structures and represented as a transformation of the pattern; accessing a first quantization parameter used for quantizing a rotation part of the transformation, wherein the reconstructed instance is determined in response to the pattern and the first quantization parameter; estimating an upper bound of a vertex coordinate error between a vertex of the instance and a corresponding vertex of the reconstructed instance, in response to at least one of (1) the first quantization parameter and (2) a distance between the corresponding vertex of the reconstructed instance and a rotation center of the reconstructed instance; determining a second quantization parameter for quantizing the vertex coordinate error in response to the estimated upper bound; and performing encoding or decoding of the vertex coordinate error between the vertex of the instance and the corresponding vertex of the reconstructed instance based on the second quantization parameter.