| With the development of 3D printing,objects in three-dimensional digital products form are widely used in many fields.Three-dimensional digital models bring great benefits to production and life,yet face threats such as illegal copying and dissemination.In order to effectively protect the copyright of 3D digital products,3D digital watermarking algorithm appeared.The paper studies digital watermarking algorithm of color point cloud model from the aspects of robustness and imperceptibility.The main work is as follows:(1)The paper proposes a 3D color point cloud model watermarking algorithm based on discrete cosine transform.The algorithm first projects the vertex of the color point cloud model onto a two-dimensional plane to obtain RGB color images.Then the discrete cosine transform is performed on the coordinate array of the projected image.Secondly,the watermark is embedded in the transformed intermediate frequency coefficient.Finally,the watermarked color image is mapped to the point cloud model to complete the watermark embedding.Experimental results show that the algorithm not only guarantees imperceptibility,but has good robust to geometric attacks,especially for scaling,translation,and rotation attacks.The change of vertex position will not affect the quality of the extracted watermark,aiming at scenes with high robustness such as copyright protection.(2)The paper proposes a 3D color point cloud model watermarking algorithm based on cepstrum transform.The algorithm first projects the color point cloud model onto a two-dimensional plane,and converts the projected color image from RGB space to YCbCr space.Secondly,the watermark is embedded into the component Cb which is insensitive to eyes.Finally,the watermarked two-dimensional image is mapped to the three-dimensional model to obtain the watermarked model.Experimental results show that the algorithm has good imperceptibility under the premise of satisfying the robustness,aiming at scenes with high imperceptibility. |
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