Fractal sorting vector-based least significant bit chaotic permutation for image encryption

The image's least significant bit(LSB) covers lots of the details that have been commonly used in image encryption analysis. The newly proposed fractal sorting vector(FSV) and FSV-based LSB chaotic permutation(FSV-LSBCP) is a novel chaotic image encryption cryptosystem introduced in this article. The FSV-LSBCP effectively strengthens the security of the cryptographic scheme concerning the properties of the FSV. Key analysis, statistical analysis, resistance differential attack analysis, and resistance to cropping attacks and noise attacks are the focus of the suggested image encryption cryptosystem. The security experiment shows that the cryptosystem is adequate to achieve the desired degree of security.

Watermarking Images in the Frequency Domain by Exploiting Self-Inverting Permutations

In this work we propose efficient codec algorithms for watermarking images that are intended for uploading on the web under intellectual property protection. Headed to this direction, we recently suggested a way in which an integer number w which being transformed into a self-inverting permutation, can be represented in a two dimensional (2D) object and thus, since images are 2D structures, we have proposed a watermarking algorithm that embeds marks on them using the 2D representation of w in the spatial domain. Based on the idea behind this technique, we now expand the usage of this concept by marking the image in the frequency domain. In particular, we propose a watermarking technique that also uses the 2D representation of self-inverting permutations and utilizes marking at specific areas thanks to partial modifications of the image’s Discrete Fourier Transform (DFT). Those modifications are made on the magnitude of specific frequency bands and they are the least possible additive information ensuring robustness and imperceptiveness. We have experimentally evaluated our algorithms using various images of different characteristics under JPEG compression. The experimental results show an improvement in comparison to the previously obtained results and they also depict the validity of our proposed codec algorithms.

Blind-restoration-based blind separation method for permuted motion blurred images

A novel single-channel blind separation algorithm for permuted motion blurred images is proposed by using blind restoration in this paper. Both the motion direction and the length of the point spread function （PSF） are estimated by Radon transformation and extrema a detection. Using the estimated blur parameters, the permuted image is restored by performing the L-R blind restoration method. The permutation mixing matrices can be accurately estimated by classifying the ringing effect in the restored image, thereby the source images can be separated. Simulation results show a better separation efficiency for the permuted motion blurred image with various permutation operations. The proposed algorithm indicates a better performance on the robustness against Gaussian noise and lossy JPEG compression.

Decryption of pure-position permutation algorithms

Pure position permutation image encryption algorithms, commonly used as image encryption investigated in this work are unfortunately frail under known-text attack. In view of the weakness of pure position permutation algorithm,we put forward an effective decryption algorithm for all pure-position permutation algorithms. First, a summary of the pure position permutation image encryption algorithms is given by introducing the concept of ergodic matrices. Then, by using probability theory and algebraic principles, the decryption probability of pure-position permutation algorithms is verified theoretically; and then, by defining the operation system of fuzzy ergodic matrices, we improve a specific decryption al-gorithm. Finally, some simulation results are shown.

An Algorithm for Boundary Extraction Based on Turning Row Permutation into Sequence Permutation

Image output by computer is done row by row,the shortcoming of which is that we cannot know the topological relations between points at the image boundary.To obtain the closed boundary of the target from an image and turn points＇ row permutation of boundary into sequence permutation,an algorithm based on 4-connection relation of pixel points is proposed and the analysis of its correctness and complexity is given.Compared with classical operators and existing method,the single pixel boundary extracted from gray images by this algorithm is more complete and more distinct.Moreover,it has a lower time complexity and can eliminate the noise inside and outside the target area.The obtained sequence permutation of points is also conducive to follow-up image processing.

A Color Image Encryption Algorithm Based on 2D-CIMM Chaotic Map

To ensure the safe transmission of image information in communication, and improve the security performance of image encryption algorithm, we proposed a color image encryption algorithm with higher security based on chaotic system. Firstly, the 2-dimensional Cubic ICMIC modulation map(2D-CIMM) is designed, which has simple form, easy to construct, and high Spectral Entropy(SE) complexity. Secondly, the hash values of the original image are used to update the initial values of the 2D-CIMM map in real time, which increases the sensitivity of the image encryption algorithm to the plaintext and improves the finite precision effect. Finally, the permutation and diffusion processes of the encryption algorithm based on bit-level are performed. In addition, simulation and performance analysis show that the proposed algorithm has higher security.

A color image encryption algorithm based on hyperchaotic map and DNA mutation

We devise a color image encryption scheme via combining hyperchaotic map,cross-plane operation and gene theory.First,the hyperchaotic map used in the encryption scheme is analyzed and studied.On the basis of the dynamics of hyperchaotic map,a color image encryption scheme is designed.At the end of the encryption process,a DNA mutation operation is used to increase the encoding images’randomness and to improve the encryption algorithm’s security.Finally,simulation experiments,performance analysis,and attack tests are performed to prove the effectiveness and security of the designed algorithm.This work provides the possibility of applying chaos theory and gene theory in image encryption.

DWT-SVD Based Image Steganography Using Threshold Value Encryption Method

Digital image steganography technique based on hiding the secret data behind of cover image in such a way that it is not detected by the human visual system.This paper presents an image scrambling method that is very useful for grayscale secret images.In this method,the secret image decomposes in three parts based on the pixel’s threshold value.The division of the color image into three parts is very easy based on the color channel but in the grayscale image,it is difficult to implement.The proposed image scrambling method is implemented in image steganography using discrete wavelet transform(DWT),singular value decomposition(SVD),and sorting function.There is no visual difference between the stego image and the cover image.The extracted secret image is also similar to the original secret image.The proposed algorithm outcome is compared with the existed image steganography techniques.The comparative results show the strength of the proposed technique.

A Novel Bit-level Image Encryption Method Based on Chaotic Map and Dynamic Grouping

In this paper,a novel bit-level image encryption method based on dynamic grouping is proposed.In the proposed method,the plain-image is divided into several groups randomly,then permutation-diffusion process on bit level is carried out.The keystream generated by logistic map is related to the plain-image,which confuses the relationship between the plain-image and the cipher-image.The computer simulation results of statistical analysis,information entropy analysis and sensitivity analysis show that the proposed encryption method is secure and reliable enough to be used for communication application.

基于改进YOLOv5的菌落计数算法研究

针对菌落计数问题,人工计数方法存在效率低、精度不高的问题。为了解决这些问题,提出了一种改进YOLOv5的模型,即YOLOES。该模型通过添加小目标检测层,并将Kmeans算法替换为Kmeans++算法,以更好地适应不同尺寸的目标;同时,采用Focal-EIoU损失函数解决难易样本的问题,引入了SPPCSPS(Spatial Pyramid Pooling Convolutional Spatial Pyramid Convolution)模块以增强特征表示能力,并在特征提取阶段引入了置换注意力机制。通过在大肠杆菌菌落数据集进行实验验证,结果显示相较于初始的YOLOv5模型,YOLOES的mAP@0.5提升了17.3百分点,表明YOLOES在菌落检测任务上具有更优越的性能。

结合自适应脉压与排列熵特征的陆海分割方法

针对陆海交接处强陆地杂波距离旁瓣影响近岸海上目标检测的问题,提出了1种自适应脉冲压缩与排列熵特征提取相结合的陆海分割方法。首先,采用两级相位补偿的自适应脉冲压缩技术,抑制近岸强地物杂波距离旁瓣对陆海分割的影响;随后,利用每个距离方位分辨单元中的观测数据计算该单元的排列熵,该特征显著增强了地物回波与海面回波的对比度;最后,利用大津法图像分割和形态学处理等数字图像处理技术,提取出陆海分界线。实测数据处理结果表明,自适应脉冲压缩与排列熵特征提取相结合,能够有效提升陆海回波的对比度,保证了陆海分界线提取的准确性。

基于嵌入式CPU+GPU异构平台的遥感图像滤波加速

针对遥感图像在轨实时处理提出一种基于嵌入式CPU+GPU异构平台的遥感图像滤波加速设计方法.以加速拉普拉斯滤波为例,利用GPU的并行计算特点,通过数据划分及数据映射的方法对算法进行并行设计;利用GPU的向量单元和缓存等硬件资源,通过采取向量化和向量重组以及工作组调优方法进一步提高了算法的运行速度.在嵌入式开发板上验证了加速设计的可行性和高效性.实验结果表明,相比于单CPU的串行实现,在增加GPU并行处理后的拉普拉斯滤波获得了4.08~16.92倍的加速比.进一步利用GPU硬件资源优化性能后,加速比可达15.38~56.41倍.

图像的排列变换

任何一幅图像的直方图都可以看作是一个多重集合，该多重集由多种可重复使用的颜色组成，而具有该直方图的任意一幅图像就是该多重集上的一个全排列．因此，可以借助于集合论和群论中的一些理论和方法来研究图像的某些性质．本文首先从多重集和置换群的角度讨论了图像和排列之间的相互关系，然后作为应用实例介绍了两种基于排列变换的图像生成方法．

图像加密技术综述

随着 Internet技术的发展 ,人们对通信隐私和信息安全技术越来越重视 .综述了图像加密技术的进展状况 ,对其中的若干图像加密技术 ,如图像像素置乱技术、基于秘密分割和秘密共享的图像加密技术、基于现代密码学体制的图像加密技术以及基于混沌动力学体制的图像加密技术的原理、特点与算法实现都做了阐述 ,并对这些图像加密技术做了分析与比较 ,指出了它们各自的优缺点和应用局限性 ,并讨论了今后的发展方向 .

基于二维Logistic映射和二次剩余的图像加密算法

针对公共网络中数字图像的安全传播问题,提出了一种基于二维Logistic混沌映射和二次剩余的图像加密算法.该加密算法利用二维Logistic映射的优良随机性,对明文图像进行2次置乱,极大地改变了图像像素位置.然后把置乱图像展开成二进制序列,按照8位一组进行分块,再利用二次剩余密码体制对每个分块进行加密,有效地改变了明文图像的信息.最后,对该算法进行直方图分析、信息熵分析、密钥敏感性分析以及明文图像和密文图像的相关系数分析等仿真实验.实验表明该算法能抵抗统计攻击、信息熵攻击,是一种较安全的图像通信方式.

基于置乱扩散同步实现的图像加密算法

基于数字图像加密设计的两个基本原则是置乱和扩散,一般的算法针对于图像分别单独进行置乱和扩散,而本文提出一种两者相结合同步实现加密的算法.先利用一维Ulam-von Neuman映射来控制二维Logistic映射产生两个混沌序列;再将产生的序列作用于原图像,对图像按照某种扫描方式,在每一个像素点上,每完成一次置乱,紧接着进行一次扩散,直到整个图像加密完成.仿真实验表明,与单独置乱扩散的图像加密算法比较,该算法有很大的密钥空间、很高的安全性、很快的加密速度和很强的鲁棒性.

基于图像相关性的混沌图像加密算法

利用图像相邻像素间的相关性,提出了一种将4个相邻的像素点"分而治之"的方法,对传统混沌加密框架中的置乱过程进行改进.首先对相邻的像素点进行分离,对分离后的4组像素点使用4组不同参数的"猫映射"进行置乱,最后再进行组合和扩散操作.模拟结果表明,该算法在保证加密算法安全性的前提下,减少了加密算法中置乱操作的次数,从而有效地减少了加密时间.

基于仿射变换的数字图象置乱技术

以图象信息安全问题为背景,分析了Arnold变换、排列变换、Fibonacci变换存在的不足,提出了一种新的仿射变换,新变换避免了取模运算且其逆变换有简洁的解析表达式,分析及实验表明新变换在进行图象置乱时效果很好,且计算时间复杂度低。

基于混沌映射的抗剪切鲁棒水印算法

在空域内嵌入水印,具有速度快、容易实现等优点,但如何提高其安全性和抗剪切能力是急待解决的难点。该文提出一种基于混沌映射的鲁棒水印算法能够解决这个问题。首先,运用二值混沌序列对水印信息加密,再用混沌映射对载体图像进行混沌置乱变换;其次,将加密水印嵌入到变换图像位平面的第4、5、6位;最后,反变换得到嵌入了水印的图像。实验表明,该算法具有较好的透明性和抗剪切能力,即使在受到剪切3/4的强攻击时仍然能提取出较清晰的水印信号。

基于随机置乱的内容感知图像缩放算法

针对非等比例缩放算法中线裁剪技术动态规划的复杂性,提出基于随机置乱的内容感知图像缩放算法。该算法利用视觉显著图随机重置能量序列的方式,使得在保护主体区域不被破坏的情况下,避免过度删除非重要区域所造成的图像局部失真。仿真结果表明,与线裁剪算法相比,本文算法在有效保护图像内容的同时,显著提高缩放速度,并能避免图像失真。