34 results about "Color image watermarking" patented technology

The invention discloses a color image watermarking algorithm with good robustness. The color image watermarking algorithm combines the advantages of a spatial-domain watermarking method and a frequency domain watermarking method, aims to improve the instantaneity and the robustness of a digital watermarking method, and satisfies a requirement of color digital image copyright protection. The color image watermarking algorithm is characterized by blocking the blue component of a color host image; acquiring the DC coefficient and the modified value thereof of each 8*8 pixel child block in each block in the spatial domain according to a DC coefficient forming principle in the DCT domain; and then modifying the DC coefficient in the DCT domain to embed a watermark by directly modifying the size of a pixel in the spatial domain; repeating 4 times to embed the child watermarks into the image blocks on the basis of the original watermark blocks; not requiring the original watermark or the original host image in watermark extraction; determining optimum extracted child watermarks by using a majority principle; and combining the child watermarks to form a complete extracted watermark. The color image watermarking algorithm is simple and convenient, good in robustness, and suitable for copyright protection of the color image used as the host image.

The invention discloses an adaptive color digital image blind watermarking method by utilizing the advantages of strong robustness of the transformation domain digital watermarking algorithm. The present invention adaptively selects different embedding coefficients in different image blocks, and modifies part of the intermediate frequency coefficients after the two-dimensional discrete cosine transform in the transform domain, thereby completing the embedding and blind extraction of the color digital watermark; in the watermark preprocessing stage , using affine transformation and Arnold transformation successively to double-encrypt the watermark, which greatly improves the security of the watermark algorithm. The invention embeds the color image watermark into the color host image, which not only has good watermark invisibility and strong robustness, but also has high security, and is suitable for the occasion of digital image copyright protection.

The invention proposes a color image digital watermarking method based on multi-transform domains, combining discrete wavelet transform (DWT), quaternion discrete cosine transform (QDCT) and singular value decomposition (SVD). First, the color image is divided into DWT channels, and then the same frequency subbands of the three channels are described by quaternions, and then divided into blocks according to the size of the watermark, and each sub-block is subjected to DQCT to form a coefficient matrix. Finally, in the guarantee Under visually perceptible quality, the watermark is embedded into the coefficient matrix. The present invention provides a new color image watermarking method. Aiming at the existing color image digital watermarking algorithm, there is still room for improvement in the relationship between robustness and transparency. By making full use of the advantages of each transformation method, under the premise of ensuring transparency, Improve the robustness and embedding capacity of watermarking algorithms.

The invention discloses a color image watermark embedding and extraction method based on fractional order hyper-chaos and discrete wavelet transform-singular value decomposition (DWT-SVD). The method includes: firstly, utilizing a fractional order hyper-chaos system to encrypt a color watermark image W0 to obtain an encrypted image W1; then converting the encrypted image W1 and an original color image I0 from RGB space to YIQ space to obtain images W2 and I1 respectively, and separating Y, I and Q components of the image; performing wavelet transform on components of the image I1 repeatedly, performing singular value decomposition on obtained low-frequency sub-bands, using components of the image W2 as watermark information to be embedded in corresponding singular values, and performing singular value decomposition on changed singular values again; and finally obtaining a color image with embedded watermark through wavelet inverse transformation and color space conversion. The color image watermark embedding and extraction method enhances imperceptibility, safety and abundant information of a watermark, has the advantages of being high in safety, strong in robustness, large in copyright information and rapid in arithmetic speed, and has strong application value.

The color image watermarking method of the present invention based on the compressed sensing mark of human visual characteristics, the steps include: 1) dividing the grayscale image used as the host image into non-overlapping blocks, sorting based on human visual feature values, selecting important blocks to formulate Reference image; 2) decompose the color watermarked image into three components, and compress it with compressed sensing and a measurement matrix generated based on Logistic mapping; 3) Combine the compressed component images to form a grayscale watermarked image, which is generated using another Logistic mapping The chaotic random phase mask modulates the grayscale watermark image, which is transformed by GT; 4) The frequency coefficient obtained from the watermark image is fused with another frequency data obtained by applying GT to the reference image, and the inverse GT is used to transform the fusion result ; 5) The inverse transform result is segmented again, where the modified important blocks are mapped to their original positions to obtain the watermarked image.

The invention discloses a double-color image blind watermarking method based on QR decomposition and compensation, which aims to change the current situation that the current digital watermarks are mostly binary or grayscale images, and meet the needs of color digital images as digital watermarks. The technical point is to embed the color image watermark into the orthogonal matrix Q obtained by QR decomposition, and use its upper triangular matrix R to compensate for the visual distortion caused by embedding the watermark; at the same time, the original watermark or the original host image should not be used when extracting the watermark. With the help of , the purpose of blind detection is achieved. The method is simple and fast, and has high watermark invisibility, strong robustness and large capacity, and the invention is suitable for copyright protection of color digital images as digital watermarks.

The invention discloses a color image blind-watermarking method. A color image for copyright protection is subjected to ternary coding and serves as a digital watermark to be embedded into a color parasite image. The embedded color image watermark has good invisibility and meets the requirement for copyright protection based on color image identification. According to the method, each 4*4 pixel block is subjected to QR decomposition, and the watermark is embedded by modifying the value of the element in the first column and the second row and the value of the element in the first column and the third row in an orthogonal matrix Q of the image; after the image containing the watermark is attacked, the embedded watermark is extracted according to the relation between the modified elements in the orthogonal matrix Q of the image, and the purpose of blind detection is achieved. The color image blind-watermarking method has good watermarking algorithm performance and is suitable for copyright protection with the color digital image as the digital watermark.

The present invention belongs to image signal processing field, in particular a significative digital watermarking algorithm of the supercomplex frequency domain. The algorithm processing quick supercomplex Fourier transform to the color carrier image, selecting proper frequency band to embed in the watermark data in the supercomplex frequency domain, and repairing the value of coefficient of asymmetry, resolving the problem of the precondition of the supercomplex frequency domain embedding in the watermark, ensuring process transmittion by the red, green, blue of the color image when embedding in the watermark image, paving a road for further study of the color image watermarking algorithm of the supercomplex frequency domain. The algorithm also provides a regulation of ''intersecting redundancy embed'' of the watermark data, further improving the Robust of the digital watermark. The analyzing result shows that the proposed method diffuses the error caused by watermark to the whole imge by supercomplex Fourier transform, and diffuses to each weight of red, green, blue colors, achieving excellent combination of the non intangibity and safety of the digital watermark.