5 results about "Arnold transformation" patented technology

The invention discloses an image encryption method and device, a program product and a medium, relates to the technical field of image processing, and provides an image encryption method aiming at the problem of insufficient security of image encryption by a traditional RNA (Ribonucleic Acid) algorithm to realize image encryption through combination of Arnold transformation and an RNA encryption algorithm. Moreover, in the image encryption process, a chaotic sequence is used to determine control parameters of Arnold transformation and a scrambling rule and a diffusion algorithm of an RNA encryption algorithm, so that the unpredictability of the algorithm is increased, and the encryption effect is improved. The chaotic system is high in key stream generation speed, sensitive to initial conditions and suitable for generating high-complexity keys at low cost. And the RNA encryption algorithm can quickly search the optimal encryption parameter, so that the calculation redundancy is reduced. The image encryption scheme provided by the method is high in complexity, relatively large in key space and good in security, can resist various attacks, and has very considerable application prospect and value for encryption transmission of the image.

The application relates to a light wavelet enhancement fusion medical image segmentation method, and belongs to the technical field of medical image processing and computer-aided diagnosis. The core of the method is to construct a light WEF-Net network, which comprises an encoder, a bottleneck layer and a decoder. The encoder adopts a dual-domain perception module, extracts complementary features from the frequency domain and the time domain through wavelet transformation and convolution, and simultaneously extracts complementary features from the frequency domain and the time domain. The bottleneck layer is designed with a feature aggregation Kolmogorov-Arnold transformation module, which is used for efficiently fusing multi-scale semantic information and enhancing the nonlinear modeling capability. The network level also integrates a sawtooth rolling feature fusion module, which enhances the global continuity of the features through the channel rolling and spatial scanning mechanism to improve the integrity of the boundary segmentation. Experiments show that the method realizes excellent performance on multiple public medical image datasets, while maintaining low parameter quantity and low computational quantity, and significantly improves the segmentation precision.

The present invention belongs to the field of geographic information security technology, and specifically relates to a vector geographic data encryption method and decryption method based on three-dimensional Arnold transformation. The method first obtains vector geographic ciphertext data, and then determines the vector geographic plaintext data corresponding to the vector geographic ciphertext data based on the constructed three-dimensional Arnold inverse transformation formula. The encryption method of the present invention is based on the three-dimensional Arnold transformation, which can convert vector geographic plaintext data into vector geographic ciphertext data. On the basis of not changing the original data structure, the vector geographic data is geometrically scrambled based on spatial transformation. It has the characteristics of simplicity, high scrambling degree, fast encryption speed, complete reversibility and resistance to enumeration attacks, and provides a performance-balanced, lightweight and efficient scrambling encryption protection option for vector geographic data encryption. The decryption method is the inverse process of the encryption method, which can simply and quickly convert vector geographic ciphertext data into corresponding vector geographic plaintext data to achieve data restoration and decryption.

The invention discloses a document image watermark adding and tampering detection method based on Chebyshev and Arnold. The watermark adding method comprises the following steps: converting a digital paper file into an image file; performing Arnold transformation on the image to obtain a scrambled image xi; converting the image xi into a Ycbcr color space, and extracting a Y channel; two-dimensional Chebyshev transformation is carried out on the Y channel; keeping coefficients greater than a set threshold value mu, and setting the rest coefficients to be zero; performing Chebyshev inverse transformation on the processed Y channel, replacing the processed Y channel into a Y channel in a Ycbcr space, converting the Y channel back to an image, and performing Arnold inverse transformation; and performing Chebyshev inverse transformation on the part of which the coefficient is smaller than a set threshold value mu, and forming encrypted global summary information by extracting noise level features. According to the method, the image storage overhead is hardly increased after the watermark is embedded, and the storage smaller than the original file in size can be obtained under partial conditions, so that the storage and transmission cost is effectively reduced.

The application relates to a video encryption method and device based on a linear fractional order hyperbolic equation and a storage medium, and the method comprises the following steps: S01) acquiring all image frames of a to-be-encrypted video, and performing normalization processing on the all image frames; S02) performing segmentation on the image frames, and performing Arnold transformation and gray scrambling operation on data information of each group of image frames after the segmentation; S03) performing encryption on the data information by using a linear fractional order hyperbolic equation encryption model; S04) performing an exclusive or operation on the encrypted data information based on a chaotic sequence to obtain ciphertext data; and S05) arranging the ciphertext data according to an initial arrangement order of the image frames. The application solves the problem that the solving efficiency of an encryption model of a fractional order partial differential equation used for video encryption in the prior art is low, and greatly increases the stability of the video encryption and decryption process.