76 results about "Digital image watermarking" patented technology

A watermarking apparatus for embedding a watermark in a digital image, an apparatus for extracting watermark information from a watermarked image using a public key having a plurality of secret keys, and an apparatus for identifying whether a watermarked image generated by embedding a watermark in each region using a unit secret key is a copy of contents. The watermarking apparatus includes: a watermark generating unit that divides the digital image into a plurality of regions, assigns predetermined secret keys to each of the divided regions, respectively, and generates a watermark for each of the divided regions using the corresponding secret key; and a watermark embedding unit that generates a watermarked image for the digital image by embedding the watermarks in the corresponding regions, respectively, and combines the watermark-embedded divided regions. Since different kinds of keys are used when watermarking and extracting watermarked information, the watermark can be protected from illegal attacks.

The invention discloses a contourlet-transform-based anti-geometric attack digital image watermarking method, mainly solving the problem of poor robustness of the existing similar method. The invention is technically characterized in that the method completes watermark synchronization through a geometric moment method to realize watermark embedding and extraction in a contourlet transform domain, that is, to calculate a first-order origin moment containing a watermark image I when the watermark is embedded, and reserve the first-order origin moment for the estimation of the geometric attack parameters during extraction; during watermark extraction, to estimate the geometric transformation parameters through the attacked first-order origin moment and a second-order center moment containing watermarks, and to recover the attacked watermarks through contourlet transform. The method of the invention has the advantages of strong anti-geometric attack ability, good watermark extracting effect and self-positioning watermark embedded location, which can be used for safety protection of digital multimedia product copyright.

The invention discloses a digital image watermark detection method based on support vector machine correction, which comprises the following steps of: extracting the phase information of an image in a high-frequency sub-band after the to-be-detected image is subjected to plural pyramid transformation, calculating the energies of Gaussian-Hermite moments on the four directions of a second level of high-frequency sub-band and taking the energies as training features; and training a sample in combination with the minimum square support vector machine theory to obtain a training model, thereby carrying out geometric correction. As the plural pyramid transformation and the support vector machine theory are combined, the digital watermark robustness can be effectively improved through the method, and meanwhile, the imperceptibility and the amount of information of a digital watermark are ensured. The digital image watermark detection method has the characteristics of simple calculation and no original carrier required in the watermark extraction, and the practicability of the watermark for digital image copyright protection is enhanced.

The invention relates to an embeding immediate gained fingerprint watermark to digit image method and device and digital camera which can embed the fingerprint watermark to digit image and detect information of fingerprint watermark. The invention belongs to fields of digital image watermark technology. The picture took by the digital camera of the invention can check the perfectness and copyright. When the image is edit, updated, added and deleted, the changing of the image can be known by checking the perfectness, so the fidelity of the image can be realized, that digital picture is as electronic evidence is possible. At the same time, because the human original fingerprint is as the watermark information, the copyright information can be identified by extracting fingerprint watermark to achieve the effect of copyright identification.

This invention relates to one digital code camera to imbed photos into high height water mark in digital image water mark technique, which adds the device and water mark imbed device to get high data in the camera to use digital water mark technique and imbeds the data height information by water mark type into digital images as future validation base to identification digital image height.

A method for embedding watermark on robust digital image of airspace image includes using chose sequence generated by cipher key to select initial image pixel block, seeking optimum matched block with said pixel block in complete image, recombining them as per their generated order and making DWT conversion, dividing watermark information as per their importance, realizing unequal error protection by utilizing orthogonal variable length OVSF code spread spectrum treatment and embedding spread spectrum watermark into DWT wavelet coefficient. The method for picking up watermark is also disclosed.

The invention discloses a DCT algorithm-based method for digital image watermark extraction, which comprises the following steps: firstly, performing the DCT domain conversion of an original image and an image to be tested respectively, performing subtraction, and determining sequence positions; secondly, comparing the variances of image blocks and sorting out texture blocks so as to determine the position at which a watermark is embedded into the image; thirdly, forming one-dimension watermark sequence according to the sequence positions; and fourthly, recombining the one-dimension watermark sequence into a two-dimension watermark and restoring the image. The method has the characteristics of an automatic compensation function and random frame increase.

Disclosed is a method, apparatus, and system to provide for robust digital image watermarking utilizing a Walsh transform algorithm. A first image processor performs operations including partitioning a cover image, generating a key, and inserting a watermark symbol into the cover image utilizing a Walsh transform and the key. A second image processor performs operations including extracting the watermark symbol from the cover image utilizing a Walsh transform and the key.

The invention discloses a depth information-based image watermarking method, belonging to the field of image information safety. The method comprises the following steps: A) obtaining distribution conditions of depth information of a host image; B) according to the distribution conditions of the depth information of the host image, determining areas to be embedded with watermarks and the quantity of the embedded watermarks in each area, wherein the greater the depth value of the area is, the greater the quantity of the embedded watermarks is; C) according to the area to be embedded with the watermarks and the quantity of the embedded watermarks in each area in the step B), embedding and extracting the watermarks. According to the method disclosed by the invention, the areas to be embedded with the watermarks and the quantity of the embedded watermarks in each area are determined according to the depth information of the host image, and the greater the depth value of the area is, the greater the quantity of the embedded watermarks is; accordingly the vision effect of the image with the embedded watermarks is ensured, moreover, under the condition of attacks by proper noise, cutting, JPEG and the like, better robustness is realized, and a new idea is provided for digital image watermarking technology.

The invention discloses a watermark embedding method based on wavelet-domain enhanced image masks, and the method is mainly used for solving the defects that just distortion thresholds of wavelet coefficients calculated by the existing method are inaccurate and nonadjustable. The method comprises the following steps: firstly performing wavelet decomposition on an input image; calculating brightness masks for the wavelet coefficients through the maximum weighted averages of background brightness and brightness variation of low-frequency sub-bands, calculating texture masks for the wavelet coefficients through local standard deviation of the compressed input image and edge masks of high-frequency sub-bands, and determining directional masks for the wavelet coefficients according to the direction of the sub-bands; and finally performing weighed synthesis on the brightness masks, the texture masks and the directional masks so as to obtain the just distortion thresholds of the wavelet coefficients. The method has the advantages that the accuracy and adjustability of the just distortion thresholds of the wavelet coefficients are improved, the watermark embedding strength is better estimated, and the visual quality of the watermark-containing image is improved; and the method can be used for evaluating the perception characteristics of eyes on a digital image so as to adaptively control the watermark embedding strength in the field of digital image watermarking.

The invention discloses digital image watermark embedding method and system thereof based on computer-generated hologram. The method comprises the steps of: fabricating an original watermark image into a Boqi type computer-generated hologram watermark according to the theory of Boqi type computer-generated hologram; segmenting an original carrier image into a plurality of subimage blocks which are not overlapped mutually, wherein each image block comprises 8*8 pixel points; respectively carrying out the Fourier transform on each subimage block; embedding the Boqi type computer-generated hologram watermark into each block subjected to the Fourier transform to obtain an embedded frequency domain image; and carrying out inverse Fourier transform on the embedded frequency image to obtain a watermark embedded image. The bargain characteristic of the Boqi type computer-generated hologram and the shearing resistance of the Fourier transform are applied to the digital watermark, the watermark is embedded in a Fourier frequency domain by blocks, and clear watermark information can be always extracted under the condition of bearing more than 80 percent of strong shearing attack.

The invention discloses a digital image watermarking method based on the local index torque characteristic. Characteristic points of an original image are extracted and screened through brightness probability density gradient Harris-Laplace operators, and a screened characteristic point image is obtained; in the obtained characteristic point image, round areas with the characteristic points as circle centers are extended into square areas, and local characteristic areas are constructed and screened; the index toque of the obtained local characteristic area image is obtained through calculation, needed stable index toque is selected, the amplitude values of the index torque are modified with a quantization index modulation method, and watermarking information is embedded; the selected index torque is respectively reconstructed before or after the watermarking information is embedded, two reconstructed images are obtained and subjected to difference value calculation, the obtained difference values are overlaid into the local characteristic areas corresponding to the original image, and small images with watermarks are obtained; watermarking information is embedded into all the local characteristic areas.

A certificate anti-counterfeiting digital watermarking processing method based on mathematical modelling comprises mathematical modelling and correction of the print-and-scan distortion of a certificate image, watermark embedment and watermark detection, wherein pixel distortion of the certificate image produced in the print-and-scan process is corrected by establishing a mathematical model; a model curve is fitted through a mass of experimental data; the certificate image after the print and scan is corrected through the obtained model curve; the watermark detection is performed on the corrected image, so that the accuracy rate of the watermark detection can be effectively increased; therefore, a new print-and-scan resilient digital image watermark algorithm based on VQIM and Discrete Fourier Transformation (DFT) is provided in combination with pixel distortion modeling and correction; and the new algorithm is to embed and detect a watermark in the DFT transformation domain of the certificate image, thus obtaining good robustness for the print-and-scan process.

The invention belongs to the technical field of digital image watermarking, and provides a robust image watermarking method and system based on deep learning and an attention network, and the method comprises the following steps: obtaining an original image tensor; obtaining an attention image tensor according to the obtained original image tensor and an attention model; generating a watermark-containing image based on the obtained attention image tensor and a watermark embedding model; generating an attacked image according to the generated watermark-containing image and the constructed attack network model; and extracting an image watermark according to the attacked image, the attention model and the deep learning model. Attention weights are deduced along two dimensions of a channel and a space by utilizing the perception capability of a human visual system to different regions and the anti-attack capability of different pixel points, and regions which have small influence on human visual perception and are good in robustness are searched for watermark embedding.

The invention relates to a printing and scanning resilient watermarking method based on mathematical modeling, comprisng the mathematical modeling and correction of pixel distortion, watermark embedment and watermark detection. Mathematical modeling and correction of pixel distortion carries out mathematical modeling to the pixel distortion of an image brought by digital halftoning, dot gain, gamma correction, quantification and other links during a printing and scanning process and corrects the pixel distortion based on mathematical modeling so as to improve the watermark detection accuracy. Watermark embedment conducts analysis based on the mathematical modeling to determine an appropriate embedded domain, further investigate the impact of embedded watermarks at different positions in the embedded domain on the robustness and capacity of watermark algorithm and the fidelity of the image and determine the reasonable embedding positions of the watermarks. Watermark detection corrects the image to be detected and extracts the watermarks according to a model curve of the changed embedded domain before and after image printing and scanning obtained from mathematical modeling analysis. The invention corrects the pixel distortion that the printing and scanning process to the image by mathematical modeling, fits the model curve through a large amount of experimental data, corrects the printed and scanned image with the obtained model curve, detects the watermarks of the corrected image and can effectively improve the accuracy of watermark detection; and novel printing and scanning resilient digital image watermarking algorithm based on DWT and DFT is presented by integrating the pixel distortion mathematical modeling and correction, and the novel algorithm carries out pixel distortion mathematical modeling and correction on a wavelet approximation subgraph of the image.

The invention discloses a digital image blind watermarking method based on two-dimensional discrete cosine transform by utilizing the advantage of high robustness of a frequency domain digital watermarking algorithm. According to the method, a part of intermediate frequency coefficients of an image block subjected to two-dimensional discrete cosine transform are selected in a transform domain, andthe embedding and blind extraction of the digital watermark are completed by modifying the size relation between the selected frequency coefficients. According to the method, the digital image watermark is embedded into the host image, so that the method not only has relatively good watermark invisibility, but also has relatively high robustness, and is suitable for occasions of digital image copyright protection.