40results about How to "Increase watermark capacity" patented technology

The invention discloses an H.264 standard motion vector-based method for embedding and extracting a fragile watermark, which belongs to the technical field of information security. Watermark information is selectively embedded into the motion vector of a frame P in front of a frame I, so that watermark capacity and fidelity are high; the watermark information comprises a frame number and a time stamp, and is encrypted with a symmetric cryptographic algorithm, so that the watermark information has attack resistance and video tampering can be positioned at a certain accuracy; and an implementation process is performed in a compressed domain, computation complexity is low and the influence on a video coding bit rate is low.

The invention provides a conversion principle based on color space in special color printing, and a special color printing image digital watermark method and system combining IWT and SVD. According tothe method and the system, a carrier image is decomposed into a special color channel, and the special color channel is subjected to IMWT conversion, then the watermark information is directly embedded into the singular value of each sub-band of the first-stage IWT. In order to improve watermark safety, Arnold scrambling encryption processing is conducted on the watermark image, and digital signature capable of resisting the printing-scanning process is embedded in the U and V of the image. In order to improve the robustness of digital signature and watermark, a step correction model for scanning a special color image is provided, and the scanned images are corrected, the digital signatures are extracted for verification, and the watermark information can be extracted if the digital signature is verified. The method has excellent performances in terms of watermark transparency, robustness and capacity, and can resist the printing-scanning process of the offset plate. The algorithm complexity is low, the execution efficiency is high, and the extraction time is not less than 1 second.

The invention relates to a webpage link protection method based on control character coding and steganography. Watermark information can be embedded through selected control characters which are not displayed at a browser end, and thus link information in a webpage can be protected. First, the webpage is partitioned into blocks according to links, watermark information with any bit is generated according to all the characters of all the sub-blocks and coded into corresponding control characters to be embedded into the webpage, and a webpage with watermarks is generated; in detection, whether the link blocks are tampered or not is judged by comparing the relations between different bit numbers and thresholds of extracted watermarks and reconstructed watermarks corresponding to the link blocks; when tampered link blocks are detected, all attribute information including link addresses is deleted, and blocks are marked with warning mark information, so that a prompt is given to a user. Through the webpage link protection method based on control character coding and steganography, link block information in the webpage can be effectively protected; when the link blocks are tampered, the tampering can be detected out in time, and false information is prevented from being propagated, so that negative effects of tampered link blocks on images ad business of enterprise and public institutions are reduced.

The invention discloses a method for embedding and extracting digital watermarks in specific to a three-dimensional point model, comprising the steps of: firstly, reconfiguring the coordinates of a model by adopting a principal component analysis method, then, forming a plurality of projected images inside a spherical surface with a gravity as a sphere by using a visual operator and taking the gravity center as a view point, converting a three-dimensional model into a two-dimensional image, regulating a spectrum coefficient of a low-frequency part by applying a two-dimensional frequency domain analysis method, and mapping the low-frequency part back to the three-dimensional model to realize the embedding and the extracting of the watermarks of the three-dimensional point model. In the invention, the calculated amount is moderate, the watermark capacity is large, and the method is suitable for large-scale point models and can be used for resisting various affine transformation attacks, achieving certain robustness to peak reordering, peak resampling and other various attacks, and effectively protecting the copyright of three-dimensional products.

Provided is a watermarking embedding and authentication method of positioning PDF electronic invoice falsification, comprising: A, watermarking generation based on a file reading page, concretely including blocking a reader page, parsing a code page file structure, generating authentication information, and generating watermarking in dependence on the authentication information; B, watermarking embedding based on file codes; C, updating of a cross reference and an end-of-file; and D, generation of a PDF electronic invoice file with watermarking, including performing E authentication information reconstruction, authentication information extraction and F falsification authentication on a PDF electronic file to be detected, and F falsification authentication including falsification authenticity determination and falsification positioning and marking. The method can guarantee invisibility of watermarking, and meanwhile control file increment within 1%. The method has the characteristics of high falsification detection accuracy, and low false drop rate, and can effectively resist replacing, adding, deleting, etc.

The invention provides a scheme self-adaptive digital watermark embedding and extracting method based on the camouflage technology. The method comprises the main steps that multiple sets of subschemes of relevant operations having both the camouflage property and the identity property are built; an index number is set for each set of subschemes, and an initial scheme sequence is obtained by arraying the subschemes in an ascending order; the BKDR Hash value of secret key information is calculated, and is used for carrying out sorting operation on the initial subscheme sequence to obtain a self-adaptive scheme sequence; according to a self-adaptive scheme sequence table, watermark information is embedded in sequence in a circulation mode. The scheme self-adaptive digital watermark embedding and extracting method has the advantages that the tamper localization function is achieved, the purpose of improving the safety of formatted text document watermark robustness is achieved by means of the camouflage technology, and the problem that watermark information is likely to be illegally extracted and then cracked due to the method of embedding watermarks by adjusting formats of formatted text document watermarks is solved.

The invention discloses a spatial domain color image blind watermarking method fused with Haar transform by combining the advantages of good concealment of an airspace digital watermarking algorithm and strong robustness of a frequency domain digital watermarking algorithm. According to the method, based on the characteristic that Haar transform has correlation between space-frequency domains, themaximum energy coefficient in a matrix of an image block after Haar transform is directly obtained in a space domain. The embedding and blind extraction of digital watermarks are completed by quantizing the maximum energy coefficient. According to the method, the color image digital watermark can be embedded into the color host image. The method has the advantages of being high in robustness, good in watermark concealment, high in safety, high in execution efficiency and high in embedding amount. The method is suitable for occasions of high-concealment high-capacity color digital image rapidcopyright protection.

The invention discloses a color blind watermarking method based on Hamming codes, eigenvalue decomposition and image correction by combining a Hamming coding theory and eigenvalue decomposition. Firstly, all characteristic values of a pixel block are obtained according to characteristics of characteristic value decomposition, and embedding and blind extraction of a digital watermark are completedby quantizing the sum of absolute values of the characteristic values; secondly, according to the geometric attributes of the image containing the watermark, the image after various geometric attackscan be corrected. According to the method, the digital watermark of the color image can be embedded into the color host image, so that the method not only has better watermark concealment and higher safety, but also has stronger robustness and larger embedding capacity, and is suitable for occasions of copyright protection of high-capacity color digital images with strong robustness.

The invention discloses a watermark embedding method and detection method based on polar-harmonic-Fourier moment, and belongs to the field of the watermark embedding and detection. A to-be-solved technical problems are that the irresistible geometric attack is existent in the existing watermark embedding and detection method, the watermark capacity is small, and partial algorithm is the non-blinddetection algorithm. The embedding method comprises the following steps: constructing an original image block; constructing a polar-harmonic-Fourier moment of the original image block; embedding watermark for the original image block, and computing the polar-harmonic-Fourier moment value of each original image block after embedding the watermark; reconstructing the original image block based on the moment value; and constructing the watermark-embedded image. The watermark detection method comprises the following steps: constructing the original to-be-detected image block; performing polar-harmonic-Fourier moment reconstruction on the original to-be-detected image block; detecting the watermark information corresponding to the amplitude of the polar-harmonic-Fourier moment value of each original to-be-detected image block based on the maximum likelihood estimation. The watermark method can resist the geometric attack and is large in capacity.

The invention relates to an embedding method and an extracting method of a color image. The embedding method comprises the following steps: carrying out lossy compression coding on a color image by adopting a JPEG compression algorithm to generate a watermark bit string; calculating a row identification number of each row of data in the data set according to the watermark embedding key; calculating a data identification number corresponding to the data in the data set according to the numerical value of the data and the row identification number corresponding to the data; determining a watermark bit position according to the watermark embedding parameter, the data identification number and the length of the watermark bit string; determining the bit of the watermark to be embedded in the data according to the watermark embedding parameter and the data identification number; embedding the watermark bit value of the watermark bit position in the watermark bit string into the bit of the watermark to be embedded in the data to obtain data with watermark bit information; and sequentially obtaining all data with watermark bit information, and obtaining a data set with color image watermarks. The method can improve the protection effect of the data copyright.

The invention discloses an anti-screen-shooting text image watermark embedding and extracting method based on deep learning. The method specifically comprises the following steps: step 1, preparing a training set and a test set; 2, establishing a screen shooting text image watermark resisting model; 3, training the screen shooting text image watermark resisting model; 4, inputting the images in the test set into the screen shooting resistant text image watermark model trained in the step 3 one by one, and detecting the accuracy of the model; and step 5, inputting a carrier image which needs to be subjected to watermark embedding into the trained screen shooting resistant text image watermark model to obtain the carrier image after watermark embedding and watermark information. The method provided by the invention has the characteristics of high watermark capacity, high robustness and strong practicability. In the actual use process, the cost is lower, the detection precision is higher, and the consumed time is shorter.

The invention discloses an anti-print-scanning text image digital watermarking method. The method comprises the following specific steps: (1) text line identification; (2) text character recognition; (3) watermark information preprocessing; (4) watermark embedding pretreatment; (5) watermark embedding; (6) image correction; (7) watermark extraction pretreatment; and (8) extracting the watermark. The text watermarking method solves the problems that the redundancy is low and the watermark is not strong in resistance to printing and scanning attacks when the watermark is embedded in the text watermarking method. According to the method, the advantages of an airspace text watermarking algorithm are utilized, the robustness to printing scanning attacks is high, the invisibility of watermarks is good, calculation is simple, and the watermark embedding capacity is high.

The invention relates to a digital watermarking algorithm of a relational database. The threat problems of copyright protection, confidentiality and privacy of content and authenticity and integrity of data faced by the security of the existing database are solved. The method comprises the following steps: 1, preprocessing data; 2, converting a watermark plaintext into a binary sequence by using aprivate key of a database copyright owner; 3, respectively executing a watermark embedding program by taking each attribute value as a non-numerical attribute column of the natural language as a unit; 4, publishing the database table embedded with the watermark; 5, when a copyright dispute occurs, carrying out watermark extraction work on the database table with the copyright dispute, and using the watermark as an effective proof of copyright affiliation; and 6, completing watermark extraction according to the personal private key of the database owner, the key corresponding to the attributecolumn, the existence of the virtual splitting column and the embedding process operation record involved in step 3. The method can be widely applied to copyright protection of character database security.

The present invention relates to an adaptive video watermark embedding method based on variance analysis, which comprises the following steps of calculating contrast and entropy for received video key frames, and discarding the frame if both the contrast and entropy are lower than a preset threshold; If it meets the requirements, go to the next step; extract the grayscale component of the key frame; perform 4*4 intra-frame prediction based on H.264 on the extracted grayscale image, and calculate the prediction residual matrix; calculate the variance of the prediction residual matrix, And generate the variance matrix of the video frame; according to the threshold th ₁ and th ₂ , divide the texture complexity of the video frame into low-texture regions S ₀ , the highly textured region S ₁ and higher texture regions S ₂ ; Perform DCT transformation on the 4*4 video frame block in the high texture area, and embed the watermark information on the DC coefficient of the DCT. The embedding method adaptively embeds the watermark information in the high texture area of ​​the video frame, and transforms the invisibility and robustness of the domain watermark.

The invention discloses a spatial domain adaptive color image blind watermarking method based on Slant transform by combining a Slant transform theory and an integer pairing theory. Firstly, the maximum energy coefficient of a coefficient matrix obtained after Slant transformation is directly solved in an airspace according to watermark capacity, a self-adaptive watermark coding mode and Slant transformation characteristics, the coefficient is quantized to complete embedding of the color watermark, and the method has good concealment and large watermark capacity; Secondly, the step length canbe adaptively quantified according to the size of the image, the geometric attributes of the attacked image can also be utilized to correct the images of various attacks, and the robustness of geometric attack resistance is high. A plurality of integer keys can be encrypted into a large integer and steganographically written into the file structure of the image, so that the security is relativelyhigh. The invention is suitable for occasions of efficient color digital image copyright protection with high safety, good concealment, strong robustness and large watermark capacity.