Digital watermark embedding and detecting method of CAD model indicated on basis of NURBS

Abstract

The invention discloses a digital watermark embedding and a detecting method of CAD model indicated on basis of NURBS, comprising: a) embedding a watermark: 1) sequentially sequencing and scrambling an NURBS curve and / or curved surface in a model, and then selecting the NURBS curve and / or curved surface which serves as actual watermark to be embedded into a carrier; 2) pre-treating watermark information; 3) using a method of inserting node in reverse to embed the watermark information section by section into the corresponding node position of each selected NURBS curve and / or curved surface; b) detecting the watermark: 1) selecting the NURBS curve and / or curved surface which serves as actual watermark to be embedded into a carrier according to the same method of step 1 in a; 2) respectively extracting the watermark information of each NURBS curve and / or curved surface; 3) combining and reducing watermark information, performing similarity analysis to the watermark information with the original watermark information, and verifying the accuracy. The invention has the advantages that the invention can accurately keep the geometric configuration of a CAD model, does not need to have the aid of original CAD model in the detecting process and has strong robustness to various common attacks.

Description

technical field [0001] The invention relates to a method for embedding and detecting digital watermarks of CAD models, in particular to a method for digital watermarking of CAD models based on NURBS representation, which is suitable for copyright protection of CAD models. Background technique [0002] With the rapid development and continuous application of the network, product data security has become a research problem. The traditional password authentication technology is powerless for any illegal copying, tampering and dissemination of digital products. Therefore, in recent years, a new digital information product copyright protection and data security maintenance technology - digital watermarking technology has been proposed internationally. After more than ten years of research and development, digital watermarking technology has been successfully applied to traditional media types such as still images, videos and texts. During this period, the basic algorithm using si...

AI Technical Summary

Problems solved by technology

[0005] 2) The current model watermarking algorithms all modify the geometric or topological information of the model to embed watermarks that are transparent in perception rather than transparent in function, but in CAD models, the geometry of the CAD model must be precisely maintained

The anti-attack ability of various existing algorithms is still relatively weak, and watermarking algorithms with strong robustness are rarely seen.

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