Non-blind Watermarking Method for 3D Mesh Model Based on Mesh Segmentation

Abstract

The invention provides a mesh segmentation-based non-blind watermark realization method for a three-dimensional mesh model, which comprises a watermark information embedment process and a watermark information detection process. The watermark information embedment process comprises the steps of significantly segmenting a three-dimensional mesh model, then calculating the robust gravity center of every segmentation block, taking every gravity center as a center to convert rectangle coordinates of the corresponding segmentation block into spherical coordinates, and finally, embedding the watermark sequence through modulating climax norm distribution of every segmentation block. The watermark information detection process comprises the steps of allowing a model to be detected and a master model to be subjected to aligning and re-sampling operation, and performing watermark extraction after the segmentation block information of the model to be detected is determined. The method provided by the invention can resist single convention attack, such as simplification, shearing and noise, and shows stronger robust in resisting combined attack.

Description

technical field [0001] The invention relates to the technical field of multimedia information security, in particular to a method for realizing a non-blind watermark of a three-dimensional grid model based on grid segmentation. Background technique [0002] Since the global watermarking algorithm is not robust to cutting attacks, people propose a block-based watermarking algorithm. The main idea is to first segment or extract several meaningful or meaningless blocks from the 3D model, and then Embed the watermark data into different blocks, that is, each block has one or several sets of watermark data. When extracting the watermark, as long as there are several blocks preserved intact, then the complete watermark can be extracted from these blocks. Watermark information. [0003] Usually, such block-based 3D mesh watermarking has the following problems: 1) After the model is attacked, the mesh block during watermark extraction cannot obtain a block result that is consistent...

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Problems solved by technology

[0003] Usually, such block-based 3D mesh watermarking has the following problems: 1) After the model is attacked, the mesh block during watermark extraction cannot obtain a block result that is consistent with the original model, especially when mesh clipping occurs. 2) The method of mesh segmentation generally cannot guarantee the boundary problem of the block model, because one more point or one less point on the boundary will not affect the visual effect of mesh segmentation, so for models that depend on model segmentation boundaries The watermarking algorithm will cause the extracted watermark data to be inaccurate due to the slight inconsistency of the boundary segmentation

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