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Abstract:This paper proposes a new fractional order total variation (TV) denoising method, which provides a much more elegant and effective way of treating problems of the algorithm implementation, ill-posed inverse, regularization parameter selection and blocky effect. Two fractional order TV-L 2 models are constructed for image denoising. The majorization-minimization (MM) algorithm is used to decompose these two complex fractional TV optimization problems into a set of linear optimization problems which can be solved by the conjugate gradient algorithm. The final adaptive numerical procedure is given. Finally, we report experimental results which show that the proposed methodology avoids the blocky effect and achieves state-of-the-art performance. In addition, two medical image processing experiments are presented to demonstrate the validity of the proposed methodology. PACS

In this paper, a novel image encryption algorithm is proposed based on a sevendimensional (7D) hyperchaotic system and simultaneous row-column swapping. First, the 7D hyperchaotic system is introduced. The SHA-512 hash function is applied in order to generate the system parameters and initial values of the 7D hyperchaotic system. Seven real numbers are transformed in order to form three new sequences. The new sequences are used for the scrambling and diffusion operations. Then, the scrambling matrix is formed, and a plain image is subjected to the permutation process. Finally, the diffusion method is performed on the scrambled image, and the cipher image is ultimately obtained. The experimental results reveal that the proposed scheme has good performance. This scheme has large secret keys and is highly sensitive to the plain images and initial keys. This method could also resist many kinds of attacks. The proposed method is superior with respect to its security and encryption performance compared with some other methods.

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Shuliang Sun, "Chaotic image encryption scheme using two-by-two deoxyribonucleic acid complementary rules," Opt. Eng. 56(11), 116117 (2017), doi: 10.1117/1.OE.56.11.116117. Abstract. An image encryption technique has been proposed using deoxyribonucleic acid (DNA) operations and chaotic map in this scheme. First, initial conditions of row encryption and column encryption are calculated. Then, a two-dimensional sine iterative chaotic map with infinite collapse (ICMIC) modulation map (2D-SIMM) is adopted to produce chaotic sequences. Extended exclusive OR (XOR) is executed to enhance security. A mask matrix is produced by 2D-SIMM. It performs XOR operation with the DNA-encoded matrix. Finally, the revised DNA-encoded matrix is performed two-by-two DNA complementary rules and executed DNA decoding to obtain the cipher image. Experiment results prove that the proposed scheme is secure enough and can resist various attacks. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI.

Bit-plane complexity segmentation (BPCS) steganography is advantageous in its capacity and imperceptibility. The important step of BPCS steganography is how to locate noisy regions in a cover image exactly. The regular method, black-and-white border complexity, is a simple and easy way, but it is not always useful, especially for periodical patterns. Run-length irregularity and border noisiness are introduced in this paper to work out this problem. Canonical Cray coding (CGC) is also used to replace pure binary coding (PBC), because CGC makes use of characteristic of human vision system. Conjugation operation is applied to convert simple blocks into complex ones. In order to contradict BPCS steganalysis, improved BPCS steganography algorithm adopted different bit-planes with different complexity. The higher the bit-plane is, the smaller the complexity is. It is proven that the improved BPCS steganography is superior to BPCS steganography by experiment.

Image encryption is an important method for protecting private data during communication. This paper proposes a novel hyperchaotic image encryption algorithm based on stochastic signal insertion and block permutation. First, the 5D hyperchaotic system is applied to generate pseudorandom number sequences. The SHA-256 hash function and secret keys are used to produce the initial values of the cryptosystem. The hash values can effectively enhance the sensitivity to plain image. To enlarge the key space and change orbit of cryptosystem, some stochastic signals are inserted during iteration. The plain image is equally divided into two parts. An X-coordinate, a Y-coordinate and a control table are established with produced pseudonumber sequences. The pixel is swapped with another pixel in the current block or another block depending on the control table. Cyclic shift is performed during the diffusion process. Performance and security analyses are executed to verify the effect of the proposed scheme. It is clear that the proposed scheme has a large key space and is highly sensitive to plain image and secret keys. Moreover, the cryptosystem has low computation complexity and can resist correlation analysis, entropy analysis, statistical attack, differential attack, noise and data loss attacks.

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