4 results about "Color image watermarking" patented technology

The present application relates to the field of digital image watermarking technology in information security, and provides a double color data image watermarking, image watermarking embedding, image watermarking extraction method and system. The double color data image watermarking method comprises an embedding process and an extraction process. In the embedding process, the color watermarking image W is encrypted by using HDNA, Mandelbrot graph and three-dimensional IPCM chaotic system to obtain an encrypted watermarking; the color carrier image is decomposed by QR decomposition, and then the encrypted watermarking is embedded into the color carrier image. In the extraction process, the encrypted watermarking information is extracted by QR decomposition, and then the original color watermarking information is extracted from the encrypted watermarking information by HDNA and Mandelbrot graph. The present application provides a safe, transparent and efficient double color image watermarking method, which has the advantages of high security, strong robustness, large copyright information capacity and fast operation speed, and has stronger application value.

In order to overcome the limitation of a traditional transform domain watermarking technology in the aspect of resisting traditional attacks and geometric attacks, the invention discloses a robust watermarking scheme based on secondary division and three-dimensional quantization, a selected image block is subjected to secondary division to obtain an upper left sub-image block, a lower left sub-image block and a lower right sub-image block, then DC coefficients of the three sub-blocks are directly calculated, and a robust watermarking algorithm is established. And watermark quantization index modulation in a three-dimensional space is carried out to realize watermark embedding, so that the resistance to noise interference and geometric attack is enhanced. The method not only has good invisibility and robustness, but also can effectively solve the problem of weak digital watermark resistance of the color image, and is suitable for occasions of digital media copyright protection.

The invention is suitable for the technical field of information hiding and digital watermarking, and provides a color image watermarking method based on vector binary statistical modeling, which comprises the following steps of: firstly, obtaining an amplitude coefficient domain by combining discrete inseparable shear wave transformation and quaternion improved polar harmonic Fourier moment suitable for a color image; the imperceptibility of the algorithm is improved, and meanwhile, the correlation between RGB channels is effectively reserved; secondly, a cross-sub-band vector binding strategy is adopted to enhance the statistical modeling capability, and a vector BIUPWD model is constructed; and finally, designing a color image watermark decoder in combination with a maximum likelihood decision criterion. The method can effectively balance the relation among robustness, imperceptibility and watermark capacity in color image watermark processing.

The invention relates to a color image watermark embedding method and system based on Walsh-Hadamard transform, and the method comprises the steps: carrying out the partitioning of a carrier image, calculating the entropy value of each image block, and carrying out the sorting preprocessing of the image blocks, the method comprises the following steps: selecting a plurality of in-block smooth image blocks as to-be-embedded image blocks, carrying out frequency conversion on the to-be-embedded image blocks through Walsh-Hadamard transform, carrying out secondary partitioning on each converted to-be-embedded image block, selecting an embedding position of a watermark according to a frequency difference value between pixel points after Walsh-Hadamard transform, and carrying out watermark embedding according to the frequency difference value between the pixel points after the Walsh-Hadamard transform. The image attack resistance of the embedded secret-carrying image is improved, and the balance between the unperceivability and robustness of the image watermark based on Walsh-Hadamard transform is improved.