Efficiently Storing Well-Composed Polyhedral Complexes Computed Over 3D Binary Images

A 3D binary image I can be naturally represented by a combinatorial-algebraic structure called cubical complex and denoted by Q(I), whose basic building blocks are vertices, edges, square faces and cubes. In Gonzalez-Diaz et al. (Discret Appl Math 183:59–77, 2015), we presented a method to “locally repair” Q(I) to obtain a polyhedral complex P(I) (whose basic building blocks are vertices, edges, specific polygons and polyhedra), homotopy equivalent to Q(I), satisfying that its boundary surface is a 2D manifold. P(I) is called a well-composed polyhedral complex over the picture I. Besides, we developed a new codification system for P(I), encoding geometric information of the cells of P(I) under the form of a 3D grayscale image, and the boundary face relations of the cells of P(I) under the form of a set of structuring elements. In this paper, we build upon (Gonzalez-Diaz et al. 2015) and prove that, to retrieve topological and geometric information of P(I), it is enough to store just one 3D point per polyhedron and hence neither grayscale image nor set of structuring elements are needed. From this “minimal” codification of P(I), we finally present a method to compute the 2-cells in the boundary surface of P(I).     

Digital Topology: Regular Sets and Root Images of the Cross-Median Filter

In the study of topological properties of digital images, which is the central topic of digital topology, one is often interested in special operations on object boundaries and their properties. Examples are contour filling or border following. In classical topology there exists the strong concept of regularity: regular sets in R² show no exotic behaviour and are extensively used in the theory of boundary value problems. In this paper we transfer the concept of regularity to digital topology within the framework of semi-topology. It is shown that regular open sets in (a special) semi-topology can be characterized graphically. A relationship between digital topology and image processing is established by showing that regular open digital sets, interpreted as digital pictures, are left unchanged when the cross-median filter is applied.     

A New Fuzzy Connectivity Measure for Fuzzy Sets

Fuzzy set theory constitutes a powerful representation framework that can lead to more robustness in problems such as image segmentation and recognition. This robustness results to some extent from the partial recovery of the continuity that is lost during digitization. In this paper we deal with connectivity measures on fuzzy sets. We show that usual fuzzy connectivity definitions have some drawbacks, and we propose a new definition that exhibits better properties, in particular in terms of continuity. This definition leads to a nested family of hyperconnections associated with a tolerance parameter. We show that corresponding connected components can be efficiently extracted using simple operations on a max-tree representation. Then we define attribute openings based on crisp or fuzzy criteria. We illustrate a potential use of these filters in a brain segmentation and recognition process.

数字图像的公开水印技术

基于领域中象素的相关性,提出一种将水印嵌入数字图像的空域的公开水印技术,首先,在图像的空域中,用密钥随机地选取一些图像象素及它们的领域,并将领域听象素排序,然后,通过调整被选象素与邻域中其它象素的大小关系来隐藏水印信息,为了提高水印的稳健性,将其重复嵌入,实验结果表明,文中方法对通常的图像处理操作是隐健的,特别地,当JPEG压缩比达1：13时,提取的水印仍可识别。     

基于灰度频率与空间连通性的运动目标检测

笔者提出一种基于灰度频率与空间连通性的运动目标检测算法。算法过程为采用初始或前一状态的前景比例值计算本帧灰度频率统计下的阈值,然后用该阈值对灰度图像进行二值化并统计二值图中不具有连通性的目标点,对于每一灰度图中首次独立点数量确定收敛方向,非首次独立点数量确定收敛完成。通过实验证明,本文算法针对不同实际场景均能有效准确检测运动目标。     

A New Algorithm for Hiding Gray Images Using Blocks

Abstract

As vast channels for communication, such as the Internet, become more popular, the security of digital media becomes a greater concern. Steganography is one of the techniques used to make detecting the transmitted data over channels more difficult, as hiding a message will reduce the probability of detecting this message. In this paper we suggest a new algorithm of steganography for hiding a gray image in one another. The cover is divided into blocks of equal sizes. Each block size equals the size of the embedding image.

The results drawn in this paper with the similarity equals 0.9717 are more improved and give the clear picture of the object.     

图像的局部约束变形技术

提出了一个基于局部约束的图像变形算法。该算法建立在一个新的C^2连续的变形模型上，局部约束包括单点约束和多点约束，用户可以交互地直接控制变形，实例计算表明，该算法十分灵活、简单和快速、变形效果很好。     

基于手机终端图像的数字水印技术

该文简要介绍了数字水印技术的基本原理。详细阐述了在手机终端的数字图像中进行信息隐藏的数字水印算法及提取算法。并编制了相应的程序对该算法进行了试验和分析。试验证明,该算法能有效地实现手机图像的版权保护。     

一种小波域数字水印算法

数字水印作为数字媒体版权保护的有效办法,近年来越来越为人们所重视。该文提出了一种基于小波变换在静止图像中嵌入数字水印的新算法;算法采用二值图像作为水印,首先利用二维离散小波变换对原始载体图像进行多级分解,然后置乱二值水印图象,将二值水印数据叠加到图象的低频小波系数上实现水印的嵌入,最后进行逆向小波变换生成嵌入水印后的图象。实验结果表明,该算法对JPEG有损压缩、滤波和噪声等水印攻击显示出较强的鲁棒性,取得了隐蔽性和鲁棒性的良好折衷。     

彩色灰度交叉融合的彩色图像渐变技术

研究图像渐变技术,存在着渐变过程不够自然以及渐变质量不够稳定的现象.为提高图像质量,针对上述图像问题,提出了一种新的彩色图像渐变技术,把渐变过程分为两个阶段,每个阶段分别进行彩色图像的灰度图转换和色彩饱和度分量调节.采用了一种新的非线性插值算法,与线性算法相比,渐变效果明显改善;与其它非线性算法相比,渐变的效果更加自然稳定,同时渐变处理的代价较小.实验结果表明,产生的渐变序列更加自然、平滑,图像效果好,同时渐变的效果有非常好的适应性.     

一种改进的数字图像置乱方法

图像置乱技术利于图像的保护,有效地保护数字图像内容为目的,结合Rijndael算法理论,提出了一种新的图像置乱算法.算法在原Rijndael算法的密钥扩展方案上进行了改进,综合运用了像素值置乱、像素位置乱、块置乱等技术,增强了图像置乱的效果.同时,算法改进了种子密钥的长度策略,使其与待加密图像的像素个数相等,以便适应于各种尺寸的数字图像,并有效提高了算法执行效率.采用图像相似度和图像直方图的评价方法对置乱的效果进行仿真计算.计算机仿真结果表明,与传统方法相比,算法对图像置乱简单高效,达到了很好的效果.     

Image-adaptive and Robust Digital Wavelet-domain Watermarking for Images

We propose a new frequency domain wavelet based watermarking technique. The key idea of our scheme is twofold： multire solution representation of image and odd-even quantization embedding/extracting watermark. Because many complementary watermarks need to be hidden, the watermark image designed is image-adaptive. The meaningful and complementary watermark images was embedded into the original image （host image） by odd-even quantization modifying coefficients, which was selected from the detail wavelet coefficients of the original image, if their magnitudes are larger than their corresponding Just Noticeable Difference thresholds. The tests show good robustness against best-known uttacks such as noise addition, image compression, median filtering, clipping as well as geometric transforms. Further research may improve the performance by refining JND thresholds.     

一种改进的TNAM灰度图像表示算法研究

图像表示在机器人、图像处理、模式识别等领域里是一个非常重要的研究内容之一.以流行的线性四元树表示方法和TNAM表示方法为研究对象,提出一种改进的TNAM灰度图像表示算法,并对算法的存储结构和总数据量进行了分析.理论分析和实验结果均表明:与流行的线性四元树表示方法和TNAM表示方法相比.改进的TNAM表示方法能更有效地减少数据存储空间,是灰度图像模式表示的一种良好表示方法.     

一种基于灰度数学形态学的水印算法

本文根据灰度图像数学形态学的特点以及小波的多尺度分辨特性,提出了一种鲁棒性较好的水印算法。首先,对载体图像和水印信息做预处理,第一个预处理是将载体图像做小波分解,分解的级数由水印信息量来确定,第二个预处理是对水印信息进行置乱;然后,对于小波分解得到的低频信息进行膨胀和腐蚀,并将膨胀的结果减去小波低频信息,同时将低频信息减去腐蚀的结果;接下来,在上一步得到的两个结果里同时嵌入有意义的水印;最后,利用小波逆变换重构含水印图像。实验结果证明,这个算法具有比较好的抗攻击性、不可见性。     

Polygonal Representations of Digital Sets

In the context of discrete curve evolution the following problem is of relevance: decompose the boundary of a plane digital object into convex and concave parts. Such a decomposition is very useful for describing the form of an object, e.g. for shape databases. Although the problem is relatively trivial in ordinary plane geometry, in digital geometry its statement becomes a very difficult task due to the fact that in digital geometry there is no simple set-complement duality. The paper is based on results given by Hübler et al. The main new contribution of the paper is the generalization of the concepts introduced by these authors to nonconvex sets. The digital geometric “low level” segmentation of the boundary of a digital object can be used as a starting basis for further reduction of the boundary by means of discrete evolution.     

高分辨率灰度图像的快速多分辨率着色

灰度图像的计算机快速着色有着广泛的应用前景,尤其足对老照片或者旧影片的彩色化处理.基于最优化的着色方法利用少量的人工标色,就能够得到好的着色效果,但是该方法在处理较高分辨率图像时需要消耗大量的存储和计算资源,有时甚至不能得到最后的结果.在最优化着色方法的基础上,文中利用图像着色的特征,提出了使用最优化着色的金字塔模型进行多分辨率着色处理的新方法,始终控制矩阵计算的规模,能够很快地得到视觉效果一致甚至更好的着色效果.实验结果也证明新方法无论在计算时间、存储需求还是最后着色的质量上,尤其是针对高分辨率图像,比原方法有了很大的改进.     

Polygonal Representations of Digital Sets

In the context of discrete curve evolution the following problem is of relevance: decompose the boundary of a plane digital object into convex and concave parts. Such a decomposition is very useful for describing the form of an object, e.g. for shape databases. Although the problem is relatively trivial in ordinary plane geometry, in digital geometry its statement becomes a very difficult task due to the fact that in digital geometry there is no simple set-complement duality. The paper is based on results given by Hübler et al. The main new contribution of the paper is the generalization of the concepts introduced by these authors to nonconvex sets. The digital geometric low level segmentation of the boundary of a digital object can be used as a starting basis for further reduction of the boundary by means of discrete evolution.     

彩色图像的W-SVD数字水印技术

水印图像经过幻方置乱和加密后采用W-SVD模板嵌入,利用人类视觉系统HVS的特性,实现了水印的自适应嵌入;改进了基于小波变换与加密的彩色水印算法。根据标准相关光谱亮度功效函数确定嵌入R、G、B子图像中的比例系数,水印的提取需要原始图像的参与,并受到密钥的限制,不知道原始图像和密钥的人无法正确地恢复数字水印,最后对该算法进行了一些基本的图像处理操作。实验表明所提出的方法具有更好的鲁棒性、不可见性和安全性。     

Connectivity Preserving Multivalued Functions in Digital Topology

We study connectivity preserving multivalued functions (Kovalevsky in A new concept for digital geometry, shape in picture, 1994) between digital images. This notion generalizes that of continuous multivalued functions (Escribano et al. in Discrete geometry for computer imagery, lecture notes in computer science, 2008; Escribano et al. in J Math Imaging Vis 42:76–91, 2012) studied mostly in the setting of the digital plane \({\mathbb {Z}}^2\). We show that connectivity preserving multivalued functions, like continuous multivalued functions, are appropriate models for digital morphological operations. Connectivity preservation, unlike continuity, is preserved by compositions, and generalizes easily to higher dimensions and arbitrary adjacency relations.     

数字图像的平滑技术

一幅原始图像在获取和传输过程中会受到各种噪声的干扰,使图像质量下降.退化会引起图像模糊,特征淹没,对分析图像不利.为了抑制噪声改善图像质量进行的处理称为图像平滑或去噪.主要分析图像在空间域平滑处理方法,相关方法的适用场合.