53 results about "Arnold transformation" patented technology

The invention provides a multi-chaotic mapping and DNA coding-integrated image encryption method and a device thereof, an image decryption method and a device thereof. The image encryption method comprises an image scrambling step used for converting a target image into RGB three color component matrixes, and respectively scrambling the three color component matrixes by adopting an Arnold transformation matrix; a matrix replacement step used for respectively carrying out coding treatment on the three color component matrixes which have been scrambled by adopting different DNA coding schemes, carrying out DNA coding treatment on a chaotic sequence generated by chaotic mapping, and overlapping the three color component matrixes after being coded with the DNA to obtain replaced color component matrixes; and a ciphertext reconstruction step used for carrying out DNA unlocking on the replaced color component matrixes, combining the obtained color component matrixes to obtain a middle ciphertext, and diffusing the middle ciphertext after a sum value is calculated and according to the bitwise XOR form. The method is high sensitivity to plaintexts and secret keys. Meanwhile, the method andthe device have a good scrambling effect and a stronger anti-statistical attack resistance.

The invention relates to an image encryption method combining three-dimensional Arnold transformation with a chaotic sequence. The method includes the steps that firstly, images are processed and converted into multi-dimensional images, pixel value data matrixes of the images are acquired, multiple times of three-dimensional Arnold scrambling transformation is conducted, and then the Logistic chaotic sequence is utilized to conduct bitwise exclusive-or operation with the images to change pixel values of the images. The three-dimensional Arnold transformation is utilized to conduct pixel position scrambling on processed multi-dimensional image data, compared with an ordinary two-dimensional scrambling technology, the scrambling degree of three-dimensional Arnold transformation is higher, then, the chaotic sequence is utilized to change the pixel values, encryption is completed, and the image encryption method has the advantages of being good in safety and high in secret key sensitivity and anti-attack capacity.

The invention relates to an image encryption method based on Arnold transformations and a Henon chaotic system. Firstly, a plurality of Arnold scrambling transformations are carried out on images, then scrambling is carried out for a second time on the images through use of a Henon chaotic sequence and then the Henon chaotic sequence is used to carry out a bit-by-bit XOR operation with images to change pixel values of the images. The two technologies are adopted to carry out pixel-value position scrambling twice so that the scrambling degree of the images is higher compared with a single scrambling technology and then the chaotic sequence is adopted to change the pixel values so that any information related to plaintext is completely hidden in the encrypted images. Therefore, the method has the advantages of being great in safety and high in anti-attack ability and the like.

The invention discloses an image watermark embedding and extracting method based on a back propagation (BP) neural network compressed domain. The image watermark embedding and extraction method is based on Arnold transformation, to support BP neural network image compression processing, and the watermark is embedded into the neural network hidden layer to the output layer weight of the carrier image almost no effect, invisibility is very strong, and more secure. In the compressed domain that BP neural network, the carrier watermarked image even after multiple attack, is still able to remember the local relationship between pixels in order to achieve the correct detection of the watermark signal, making this embedding and extracting methods images of a variety of conventional attack has strong robustness, good balance contradictory and robust image watermarking imperceptibility between, and enables the blind to detect the watermark image.

The invention relates to zero-watermarking embedding and extracting methods and zero-watermarking embedding and extracting devices based on DWT and PCA compression. When a watermark is embedded, improved Arnold transformation is used to transform an original watermark; a compression image is obtained by using wavelet transformation and PCA compression methods; and XOR operation is carried out on the compression image and a scrambled watermark image to obtain a characteristic matrix. When the watermark is extracted, discrete wavelet transformation is carried out on a carrier image with zero-watermark, the PCA compression method is used to compress a low-frequency sub-band image, XOR operation is carried out on the obtained matrix and the characteristic matrix, the scrambled watermark image is obtained, and a reverse Arnold transformation formula is used to obtain the original watermark image. According to the method and device of the invention, zero watermark is easy to construct and extract, and the safety and anti-attack capability of the watermark are improved effectively.

The invention discloses a medical image robust watermarking method based on Arnold scrambling transformation and DCT (discrete cosine transformation), belonging to the field of multimedia signal processing. The method comprises the following steps: firstly embedding a watermark, specifically including (1) carrying out Arnold transformation on the watermark to be embedded to implement the pretreatment, (2) carrying out overall image DCT transformation on a medical image, and extracting a vector of a feature in a transformation domain, (3) obtaining a binary logic sequence through a Hash function by using the feature vector and the pre-treated watermark; and then carrying out watermark extraction, specifically including (4) carrying out overall image DCT transformation on a medical image to be tested, and extracting a feature vector; (5) extracting the watermark by using the property of the Hash function and a binary logic sequence of a third party; and (6) obtaining the original watermark through inverse transformation of the Arnold scrambling transformation. The experiment shows that the method has a very good information hiding capability and is of great significance in protecting the information of a patient in telemedicine.

The invention provides a self-adaptive audio blind watermark method based on an auditory model. Arnold transformation, dimension reduction processing and chaotic transformation are performed on a watermark signal so that watermark information is obtained; a human ear auditory masking threshold is calculated; a watermark embedding segment and an embedding position are self-adaptively selected; embedding of a digital watermark is performed; audio segment recombination is performed, and all the audio segments without embedding of the watermark and the audio segments with embedding of the watermark are recombined so that audio signals containing all the watermarks are formed; and the digital watermark is extracted. The watermark information of large energy is embedded under the premise that the watermark signal does not influence the audio quality so that self-adaptive selection of the watermark embedding segment, the watermark embedding position and the watermark embedding strength can be realized, the imperceptibility of the algorithm can be guaranteed and the watermark robustness and the watermark embedding capacity can be enhanced. The human ear auditory characteristic can be utilized in a more detailed way so that the method has better hiding performance, the security of the watermark can be further guaranteed and the attack of common signal processing can be effectively resisted.

The invention discloses a cat mapping and chaos based image information fusion and encryption method, which mainly solves a problem that an existing technology of performing encryption on an image by using a chaotic system is insufficient in scrambling and relative poor in safety. Implementation of the method comprises the steps of 1, performing generalized Arnold transformation on an image to acquire a preliminary scrambling image; 2, acquiring a chaos generation image matrix with the length and width being four times of those of the image to be encrypted by using a generalized three-dimensional Henon hyper-chaotic system; 3, acquiring a binary substring sequence for scrambling by using Lorentz chaos; 4, inserting the preliminary scrambling image into the chaos generation image matrix by using the binary substring sequence to acquire an image matrix after insertion; and 5, reducing the image matrix after insertion by using an image information fusion technology so as to acquire a final encrypted image. The method disclosed by the invention is high in scrambling degree and high in sensitivity, improves the safety of image encryption and can be applied to information security.

The invention discloses an image hiding method based on a video carrier and under an off-line controllable mechanism. A key frame of a video is firstly subjected to 2-DWT transformation; then Arnold transformation is carried out on sub-bands; through characteristics of singular value decomposition and multi-resolution characteristics of wavelet transformation, images are embedded in sub-band singular values which have undergone scrambling; when the video is under different attacks, blind extraction of the image can be realized; and the blind extraction specifically comprises two steps which are color image confidential storage and color image extraction checking. As technology of embedding and extraction of the color image in the video and the technology of limited frequency checking and anti-copying in an image off-line condition, the method of the invention is the image confidential storage technology based on the video carrier and under the off-line controllable mechanism, and can solve problems of confidentiality and storage of confidential and private images, thereby reaching a purpose of protecting private and confidential information, and realizing validity and controllability access of the image in an extent of competence.

The invention provides image encryption and reading methods and devices, and relates to the field of image encryption. The image encryption method comprises: performing Arnold transformation on an original image to form a scrambling image; and according to a Chen' chaotic sequence, encrypting the scrambling image to obtain an object image. According to the methods and devices provided by the invention, first of all, an image is scrambled through the Arnold transformation, then encryption processing is carried out by use of the Chen' chaotic sequence, the whole process is simple and easily implemented, the secret key space is large, and the security is high.

The invention discloses a fractional domain image encryption method based on Arnold transformation and compound chaos and mainly solves the problems that the scrambling degree is low, the secret key sensitivity is low and the robustness is poor in the prior art. The method comprises the following implementation steps: (1), carrying put generalized Arnold transformation on an image so as to obtain the preliminarily scrambled image; (2), carrying out random phase encoding on the scrambled image so as to obtain the encoded image; (3), carrying out fractional Fourier transformation on the encoded image so as to obtain the transformed image; (4), generating a sequence used for scrambling by using a compound chaotic system and processing the sequence so as to obtain the processed chaos sequence; and (5), carrying out secondary scrambling on the transformed image by using the processed chaos sequence so as to obtain a final encrypted image. The method is high in scrambling degree, strong in sensibility, and good in robustness, improves image transmission security and can be applied to information security.

The invention discloses an image information encryption and decryption method based on improved Arnold transformation and LSB. The method includes: using the improved Arnold transformation to preprocess an image, and using an LSB algorithm to embed the preprocessed image into a background image to form a new image with the encrypted image. The encryption process mainly includes: calculating the information quantity which can be contained by the background image, inputting a key, using the improved Arnold transformation to preprocess a hidden-information image, saving the size of the hidden-information image, and using the LSB algorithm to embed the hidden-information image into the background image. The decryption process mainly includes: extracting the size of the hidden-information image, using the LSB algorithm to extract the hidden-information image, inputting a key and performing reverse Arnold transformation on the extracted hidden-information image so as to achieve decryption. By the image information encryption and decryption method, information confidentiality is enhanced greatly.

The present invention provides an image encryption method based on two-dimensional Arnold transformation, and belongs to the technical field of encryption. The method comprises: expressing a two-dimensional planar image with a binary function I=f (x, y), performing two-dimensional Arnold transformation on the image f(x,y), and changing a layout of a gray value of an original image by changing pixel coordinates; and taking the original image as a matrix, wherein an image subjected to Arnold transformation is ''messy'', and due to periodicity of Arnold transformation, continuing using Arnold transformation, which can reproduce the image, so as to decrypt the image. According to the method, periodicity of Arnold transformation is used, that is, the original image can be reproduced when iteration is performed to a certain step. Compared with other encryption methods, image encryption and decryption become easier, so that image encryption efficiency is greatly increased.

The invention discloses a robust watermarking technology for medical images on the basis of Arnold scrambling transformation and DWT (discrete wavelet transform)-DFT (discrete Fourier transform), and belongs to the field of multimedia signal processing. The robust watermarking technology includes embedding watermarks and then extracting the watermarks, and particularly includes steps of (1), performing Arnold transformation for watermarks to be embedded; (2), performing DWT for a medical image, performing DFT for approximation sub-images of the medical image, and extracting vectors of a feature; (3), generating a binary logic sequence via a Hash function by the vectors of the feature and the preprocessed watermarks so as to complete the process for embedding the watermarks; (4), performing DWT for a medical image to be measured, performing DFT for approximation sub-images of the medical image to be measured and extracting vectors of a feature; (5), extracting watermarks by the aid of the Hash function and a binary logic sequence stored in a third party; and (6), obtaining the original watermarks via Arnold inverse transformation so as to complete the process for extracting the watermarks. The robot watermarking technology has an important significance in protecting information of patients during remote medical treatment.

The present invention discloses a fragile watermark embedding and detection method of an MPEG-2 compressed domain video. An MPEG-2 decoder is employed to analyze the MPEG-2 video code flow according to the MPEG-2 video coding standard, the nonzero coefficient number of a brightness block Y component, a chroma block U component and a V component through DCT transformation and quantification are subjected to statistics according to the macro-block data of the I-frame video, the energy difference statistical value of the brightness block Y component is calculated according to the mapping relation; and the binary system watermarking information is generated through the Arnold transformation to embed the video code flow. The fragile watermark embedding and detection method of an MPEG-2 compressed domain video generates watermarking according to the video macro block to provide reliable watermarking embedding and detection for MPEG-2 digital products and is able perceive tiny attack; the watermarking embedding detection based on the compressed domain has no influence on the video quality, the calculation complexity is low, and the timeliness is good; and the fragile watermark embedding and the detection method of MPEG-2 compressed domain video performs watermarking detection with no need for original video and belongs to a blind watermarking method.

The invention discloses a video content protection method and apparatus based on watermarks. The apparatus comprises a watermark information generation module and a watermark information embedding module. The watermark information generation module generates binary images of a check identifier and a copyright identifier according to a watermark capacity threshold, performs Arnold transformation on the binary images, generates image bit strings and encrypts the image bit strings with private keys to generate watermark information. The watermark information embedding module decodes the video images to obtain a video stream, and embeds the watermark information of the appropriate intensity in key frame transform domain intermediate frequency coefficients. According to the video content protection method and apparatus based on the watermarks, digitalal watermarks of the video content can be relatively well realized, and the digit watermarks in the invention has a relatively high encryption degree and safety degree.

The invention discloses a multi-image encryption device based on a computer generated hologram and a multi-image encryption algorithm thereof. The multi-image encryption device comprises an input signal surface, a first random phase plate, a second random phase plate and an output signal surface which represent an input surface, transformation surfaces and an output surface from the left to the right. The image can be clearly displayed under the condition of ensuring information security, and the optical path is simple without transformation lens. Wavelet transformation and Fresnel double random phase encryption are used so that the design system is enabled to have high parallelism and transmission performance. Double encryption of the Arnold transformation scrambling mode is used so that the image decoding difficulty can be greatly increased and storage and transmission of the encrypted hologram are facilitated. The experiment verifies and proves that the method has great robustness and has great encryption effect.

The invention belongs to the technical field of digital image copyright protection, and particularly relates to a color image zero watermarking method based on rapid quaternion generalized polar complex exponential transformation. The invention provides a color image zero watermarking method based on fast quaternion generalized polar complex exponential transformation, and the method comprises thesteps: firstly, calculating the fast quaternion generalized polar complex exponential transformation FQGPCET of an original carrier image, carrying out the moment selection, and constructing a hybridlow-order moment feature with the good robustness and discrimination; secondly, utilizing asymmetric Tent mapping with good security to encrypt and convert the feature vector into a feature map; then,, scrambling the feature map and the watermark image by using generalized Arnold transformation, and taking the XOR of the scrambling results of the feature map and the watermark image to obtain a zero watermark image which can be used for copyright authentication; and finally, in order to ensure that the copyright can be publicly verified, enabling the credible mechanism to authenticate the zerowatermark, the secret key and the copyright owner identity information and adds a digital timestamp.

The invention provides an image compression encryption and decryption method based on compressed sensing and DNA coding, and the method comprises the steps: taking an original image as a parameter of an SHA-256 hash function, and obtaining a hyper-chaos Bao system integer sequence and a Logistic chaos integer sequence; converting the Logistic chaotic integer sequence into a second matrix; carrying out sparse and Arnold transformation on the original image by using wavelet transformation; constructing a Hadamard matrix as a measurement matrix based on the compression ratio; performing compression measurement on the image after sparse decomposition by using the measurement matrix to obtain a first matrix; carrying out block processing on the first matrix and the second matrix, and carrying out DNA coding, operation and decoding on each small block; dynamically controlling DNA coding, decoding and operation modes by a hyper-chaos Bao integer sequence; and combining all sub-blocks to obtain an encrypted image. The defect that traditional compressed sensing cannot resist plaintext attacks is overcome.

The invention relates to an IWT-Schur-based region-of-interest reversible watermark embedding and extracting method. The method comprises steps of during watermark embedding, firstly, performing wavelet decomposition on a carrier image, screening to obtain a region-of-interest coefficient of each component, then encrypting the watermark by using Arnold transformation, carrying out integer wavelettransformation on the scrambled watermark to obtain a series of sub-bands, and finally, correspondingly embedding each sub-band of the watermark into each sub-band ROI of the carrier image by using matrix Schur decomposition. Compared with the prior art, the method has the advantages that nondestructive recovery of the region of interest is guaranteed, it is guaranteed that the watermark is completely embedded into the whole region of interest, and the watermark can better adapt to the ROI coding characteristic.

To improve the image encryption efficiency, under the inspiration of a famous external equipment on-line parallel operation (Simultaneous Peripheral Operations On-Line, Spooling) system, an idea of changing time in space is adopted to design rapid a color image rapid encryption method based on pre-storage and three-dimensional Arnold transformation. Before encryption, T new transformation matrixesin a period are pre-calculated and are respectively stored in T text files. And during encryption, reading the corresponding new transformation matrix from the t th text file (t belongs to [1, T-1]),and new three-dimensional Arnold transformation is carried out on an original image once to obtain an encrypted image. Experiments show that the method is simple to operate and easy to implement, andthe image encryption efficiency can be obviously improved.