77 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 encrypted kinoform based digital image watermarking embedding and extracting methods and systems. The digital image watermarking embedding method comprises the following steps of: transforming an original watermarking image through non-cascaded phase recovery and random fractional fourier transform (RFrFT) to acquire an encrypted kinoform of the original watermarking image; and adaptively embedding the encrypted kinoform into a carrier image based on a human visual system (MVS) model. In the invention, the safety of the watermarking of the kinoform is enhanced by using a non-cascaded iterative encryption method; meanwhile, blink watermarking is realized by adopting an adaptive embedding algorithm; and experiments verify that extremely high robustness against various attacks is achieved, and the safety performance is extremely high.

The present invention relates to a digital image watermarking apparatus and method. Luminance component of a digital image are transformed into coefficients of a frequency domain, and watermark is generated by encrypting a user key and generating pseudo random number from encrypted user key. Then, a replacement coefficient generated from a coefficient of a first frequency area and the watermark is replaced with a coefficient of a second frequency area so that the watermark is embedded into the digital image. The embedded watermark is extracted at an authenticating apparatus and the digital image is authenticated by finding the correlation between the extracted watermark and watermark for authentication.

This invention relates to a method and apparatus for inlaying watermark in digital image and digital camera capable of adding watermark, which comprises a device to acquire signal and read out signal value, a device for bit division to divide the pixel data of digital image into the bit for image eigenvalue calculation, the bit for hiding watermark, and the bit for location interpolation area; an initialization device for location interpolation area to set the all bits as zero or one, a device to calculate eigenvalue of digital signal, a encipher device for the eigenvalue, and a watermark- embedding device to embed eigenvalue information into the digital signal.

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.

A digital image watermarking method based on visual perception characteristics provided by the invention relates to the technical field of information hiding and digital watermarking in multimedia information security, and mainly comprises the following five steps: preprocessing a digital image watermark; extracting an important region; creating a visual perceptual model; embedding the digital image watermark; and detecting the digital image watermark. A specific flow comprises the following steps: firstly, mapping a carrier image into a geometrical invariant space by using an image normalization method based on moment, and determining the important region in the normalized image by combining an invariant centroid theory; and then, establishing the visual perceptual model according to the visual perception characteristics; and finally, combining the visual perceptual model, and using a special adaptive quantization modulation policy to adaptively embed a 256-bit readable watermark in a DFT (discrete Fourier transformation) area of the important region. An original carrier is unnecessary for extracting out the watermark, so that blind detection is realized well. The method is not only good in transparency, but also has better robustness.

The invention discloses a digital image watermark method based on a visual attention mechanism. The digital image watermark method comprises the following steps of: firstly partitioning an image remarkable area by a visual attention mechanism module, obtaining a high-frequency area relative to the remarkable area by wavelet transform, continuously carrying out watermark embedding on dithering quantification modulation of coefficients of the high-frequency area, and dynamically regulating quantified step length depending on a JND (just noticeable difference) visual module in a quantification modulation process. Through the digital image watermark method based on the visual attention mechanism, disclosed by the invention, the step length is dynamically quantified and the watermark is embedded by combining the characteristics of human vision; when the robustness of the watermark is stabilized, the imperceptibility of the watermark is greatly balanced; and simultaneously, the influence of an image background area subjected to operations, such as filtering, noise pollution and the like, in the correctness of a watermark extracting result is further reduced to a certain extent by the introduction of a vision attention mechanism module; and the robustness of watermark detection is further improved.

The invention provides electronic stamp based visible digital image watermark embedding and detection methods. The embedding method comprises the following steps of S10: representing a to-be-embedded watermark by using the values of ASCII codes and then converting the codes according to predetermined rule and mapping relationship; S20: scanning an electronic stamp of the to-be-embedded watermark to obtain pixel information of the to-be-embedded watermark; S30: according to the obtained pixel information and watermark information, confirming watermark embedding way and position; and S40: according to the confirmed watermark embedding way and position, performing watermark embedding.

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.

A detecting method and device for the embedding of bit flow robust digital image watermark are disclosed that belongs to the digital image watermark technique, the data is embedded in the digit image and can be extracted accurately, even if the picture is processed by image operation, for example, magnification, contraction, rotating, inverting, mirroring, printing-scanning and so on. It includes two parts of embedded digit watermark and detecting digit watermark. A method and device for embedded digit watermark include: the data is encoded and modulated, and the encoded signal form an axial symmetry cycle watermark are embed into the digit image self-adaptively. The method and device for detecting the watermark include: calculating the auto-correlation function of forecasting watermark, judging the affine transformation parameter which the image undergo by the coordinate of auto-correlation function local peak value, and recovering the image according to the parameter. Finally, forecasting the watermark from the recovered image, and the data is extracted after demodulation and decoding.

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 a digital image watermarking method based on Cauchy statistical modeling, wherein the method includes steps of selecting a NSST sub-band with biggest host image energy as an optimal sub-band; modifying its coefficient by multiply embedding method, performing reversed NSST on the sub-band of the modified coefficient and other sub-band, and acquiring the watermarking-containing image; secondly, estimating the rotating angle of the watermarking-containing image at the receiving end through two perpendicular axial lines at the DFT frequency spectrum and amplitude center, correcting and restoring the image; performing the NSST on the corrected watermarking-containing image; selecting a high-entropy block of the sub-band with biggest energy and modeling the coefficient by the Cauchy distribution; estimating the model parameter by the coefficient of the part without watermarking part according to the internal coefficient dependency; using the local maximum potential checking method, and designing a local optimal detector to extract specific watermarking information.

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 DCT algorithm-based method for digital image watermark embedment, which comprises: a first step of reading an original public image and a light and shade watermark image into two-dimensional arrays I and W respectively; a step two of dividing the original public image I and the watermark image W into 2*2 image blocks which do not cover each other respectively, computing the average gray m and a variance sigma of the sub blocks, and performing the DCT conversion of the sub blocks of the public image; a step three of embedding one element W(p,q) in the light and shade watermark in a sub block with a complex texture; a step four of performing the inverse DCT conversion of image blocks embedded with watermark information; and a step five of combining image the image blocks to obtain an image embedded with the light and shade watermark. The method is characterized by counterfeit prevention, falsification prevention, verification, and data security and integrity guarantee.

Methods and systems for watermarking of digital images are presented. In one aspect, a method of embedding information in a digital image includes transforming the digital image to a set of coefficient blocks having coefficients in a frequency domain, embedding a watermark-indicator in one or more of the coefficient blocks, and embedding a watermark in one or more watermark blocks that have a predetermined number of coefficient blocks. The embedded watermark is substantially invisible in the output watermarked digital image. Another aspect is a method of extracting a watermark from a digital image that includes transforming a digital image to a coefficient matrix, determining if the digital image is watermarked based on a predetermined watermark-indicator, and retrieving a watermark from a projected watermark block of a projected watermark block distribution.

A watermarking device for embedding a watermark into a digital image, a device for extracting watermark information from a watermarked image using a public key having a plurality of secret keys, and a device for identifying The unit secret key embeds a watermark into each area to generate a watermarked image whether the device is a copy of the content. The watermarking device includes: a watermark generating unit that divides a digital image into a plurality of regions, assigns a predetermined secret key to each divided region, and generates a watermark for each divided region using a corresponding secret key; and a watermark An embedding unit that generates a watermarked image of the digital image by embedding watermarks into corresponding regions, respectively, and combining the divided regions in which the watermarks are embedded. 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 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 discloses a watermark embedding method for a host image and a watermark extracting method for an image including a watermark. The watermark embedding method for the host image comprises the steps that (S101) when the pixel of the host image is judged to be not the power of two, the pixel is adjusted to be the power of two through pixel processing; (S102) when the pixel of the host image is judged to be the power of two, NSCT transformation is conducted on the host image to obtain an image multi-resolution coefficient, and a watermark image is compressed with a compressive sensing algorithm to obtain a sparse coefficient of the watermark image; (S103) the sparse coefficient is embedded in the image multi-resolution coefficient with an embedding algorithm, and a coefficient including watermark information is obtained; (S104) NSCT inverse transformation is conducted on the coefficient including the watermark information, and the image including the watermark is obtained. Through the watermark embedding method for the host image and the watermark extracting method for the image including the watermark, the imperceptibility and the robustness of the digital image watermark can be effectively improved.

The invention relates to a device embedding acquired iris watermark to the digital image. It adds a device for acquiring iris data and a watermark embedding device in the digital camera. Using the original iris of the photo taker as the watermark acquiring the digital iris information of the photo taker in the mean time of photo taking, to verify the copyright information. It will not affect the picture quality.

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 discloses a multi-correlation HMT model-based digital image watermark embedding and extraction method. The method comprises the steps of firstly selecting an NSST domain sub-band with the maximum energy in a host image as an optimal sub-band of watermark embedding, modifying a coefficient of the sub-band in a multiplicative embedding mode, and combining the sub-band with the modifiedcoefficient and other sub-bands for performing NSST reconstruction to obtain a watermark image; selecting high-entropy blocks in the NSST domain sub-band with the maximum energy in the watermark image, performing modeling on the coefficient of the sub-band by using BKF-VB-HMM, and estimating parameters of a model by utilizing coefficient correlation among intra-sub-band, inter-scale and intra-scale directions; and finally, designing an optimal detector by utilizing a maximum likelihood test method to detect specific watermark information embedded in each high-entropy block, and performing sorting in sequence to obtain a final watermark sequence.

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.

A digital image watermarking method is provided. The digital image watermarking method includes the steps of combining host image data sets and signature image data sets by a predetermined method for combining the sets to be linearly independent, and generating a watermarked image and a key from the combined image. A signature image embedded in a combined image is similar to the combined image in view of existence and durability.