Embedded zerotree coding method on basis of inverse Loop subdivision

Abstract

The invention relates to an embedded zerotree coding method on the basis of inverse Loop subdivision, which comprises the following steps of: (1) constructing an offset wavelet tree, i.e. forming an offset d by obtaining difference of an actual vertex O and a forecast vertex O' and simultaneously, establishing a corresponding quad-tree relation of edges in each mesh Mj-1 and four edges in a thinner layer mesh Mj, wherein the offset d is generated on a corresponding edge of a delete vertex reconstruction mesh; (2) carrying out offset wavelet processing and selecting a threshold value; and (3) encoding and carrying out code-stream ordering, wherein important information is preferentially encoded by adopting an embedded encoding mode on the basis of a three-dimensional graph triangular mesh and a result obtained after compression is placed at an initial part of a code stream. The invention provides the embedded zerotree coding method on the basis of inverse Loop subdivision, through which compression efficiency is greatly improved.

Description

technical field

[0001] The invention relates to the technical field of digital media, in particular to a coding method for computer three-dimensional graphics. Background technique

[0002] Two-dimensional image compression has been widely used in applications, among which embedded zerotree coding is one of the effective methods. Image embedded zero-tree coding includes three processes:

[0003] (1) Zero tree prediction, encoding important images with zero tree structure, successive approximation quantization. The wavelet-transformed image forms a tree structure according to its frequency band from low to high. The root of the tree is the node of the lowest frequency sub-band. It has three children located in the corresponding positions of the three sub-low frequency sub-bands. See figure 1 upper left corner. The nodes of the remaining subbands (except the highest frequency subband) have four children located in the corresponding positions of the higher-level subband (due...

Examples

Embodiment Construction

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] refer to Figure 1 ~ Figure 4, an embedded zero-tree encoding method based on inverse Loop subdivision, the Loop subdivision surface may simplify and decompose the triangular mesh through inverse transformation to generate a progressive mesh (see patent for details: A progressive network based on inverse Loop subdivision Grid generation method, patent number: ZL2006101241528), the vertices and triangles contained in the base grid are greatly reduced, but every time an edge is deleted, an offset information is generated, so the offset information occupies a large storage space. Since the simplified model does not have a large mutation between adjacent points in the triangular mesh, and there is a good correlation between adjacent points, the offsets generated by the simplified prediction process are often small in value. Most of them have the characteristics of ...

technical field

[0001] The invention relates to the technical field of digital media, in particular to a coding method for computer three-dimensional graphics. Background technique

[0002] Two-dimensional image compression has been widely used in applications, among which embedded zerotree coding is one of the effective methods. Image embedded zero-tree coding includes three processes:

[0003] (1) Zero tree prediction, encoding important images with zero tree structure, successive approximation quantization. The wavelet-transformed image forms a tree structure according to its frequency band from low to high. The root of the tree is the node of the lowest frequency sub-band. It has three children located in the corresponding positions of the three sub-low frequency sub-bands. See figure 1 upper left corner. The nodes of the remaining subbands (except the highest frequency subband) have four children located in the corresponding positions of the higher-level subband (due...

Examples

Embodiment Construction

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] refer to Figure 1 ~ Figure 4, an embedded zero-tree encoding method based on inverse Loop subdivision, the Loop subdivision surface may simplify and decompose the triangular mesh through inverse transformation to generate a progressive mesh (see patent for details: A progressive network based on inverse Loop subdivision Grid generation method, patent number: ZL2006101241528), the vertices and triangles contained in the base grid are greatly reduced, but every time an edge is deleted, an offset information is generated, so the offset information occupies a large storage space. Since the simplified model does not have a large mutation between adjacent points in the triangular mesh, and there is a good correlation between adjacent points, the offsets generated by the simplified prediction process are often small in value. Most of them have the characteristics of ...

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