基于邻域比较的JPEG 脆弱水印算法及性能分析

为提高篡改检测性能和协调安全性与不可见性之间的矛盾,提出一种利用邻域比较判定图像块真实性的JPEG脆弱水印算法.该算法将原始图像分成8×8的图像块,基于图像块保护DCT系数生成的4比特水印基于密钥随机嵌入到其他4个图像块量化步长较小的DCT系数最低位.通过比较该图像块与相应4个水印嵌入块8邻域中不一致图像块个数来判定该图像块的真实性,推导给出一般篡改和拼贴攻击下算法的虚/漏警率,并利用统计实验对理论分析结果进行验证.理论分析和实验统计结果表明,通过比较图像块与其相应水印嵌入块8邻域中不一致图像块个数能够提高篡改检测性能,在量化步长较小DCT系数的最低位嵌入水印,解决了保护DCT系数个数与不可见性之间的矛盾.     

DNA微阵列图象信息的自动提取

微阵列图象分析是分子生物学中DNA微阵列杂交实验数据测定过程的一个重要部分。其目的是将微阵列图象中大量象素灰度信息简化为微阵列靶点的信号值。该文介绍了一种对DNA微阵列图象信息进行自动提取的方法,使用此方法完全不需要人为操作,可避免操作者主观性对实验的影响,提高数据提取的效率和可重复性。其关键步骤包括:图象滤波,图象灰度信息提取,微阵列间距确定,靶点定位和靶点信号值计算。实验结果表明使用此算法提取DNA微阵列图象信息具有重复性好、效率高和分析准确的特点。     

Effective composite image detection method based on feature inconsistency of image components

This paper proposes an effective composite image detection method that uses the feature inconsistency of image components of the composite image to detect tampered regions. The composite image is first divided into image components. Next, the variance of the noise remaining after de-noising in each image component is calculated and used as a feature. Finally, tampered regions are detected using this feature based on a tampering detection rule. Experimental results show that the proposed method has good composite image detection performance.     

扫描图象的圆弧的定位识别算法

提出对扫描图象圆弧的定位算法。该算法分为两步：第一步对图象进行条块化,条块化就是把原图象的黑象素依据一定的条件合并若干个块;第二步就是在第一步的条件化基础上,提取候选圆弧链,进而对圆弧圆心,半径,弧的起始点和终止点进行准确定位。实验对圆弧的识别处理。     

Multi-block dependency based fragile watermarking scheme for fingerprint images protection

For traditional fragile watermarking schemes, isolated-block tamper which will destroy the minutiae of the fingerprint image can hardly be efficiently detected. In this paper, we propose a multi-block dependency based fragile watermarking scheme to overcome this shortcoming. The images are split into image blocks with size of 8 × 8; a 64-bit watermark is generated for each image block, and then equally partitioned into eight parts. Each part of the watermark is embedded into another image block which is selected by the corresponding secret key. Theoretic analysis and experimental results demonstrate that the proposed method not only can detect and localize the isolated-block tamper on fingerprint images with high detection probability and low false detection probability, but also enhances the systematic security obviously.     

Two-stage dither to enhance gray scales based on real-time motion detection in plasma display panel

In order to reduce gray scale loss in low and middle-high gray scale ranges which are caused by inverse gamma conversion and limited gray scale method for dynamic false contour (DFC) improvement, respectively, and enhance gray scales both in static and moving regions of an image, two-stage dither based on real-time motion detection method is proposed. Firstly, the image is divided into blocks, and the motion state of each image block is detected according to real-time motion detection method. So limited gray scale method to improve DFC can only be used in moving image blocks. Then, ordered dither and random dither combined with minor pixel separation (MPS) are used to improve gray scale loss caused by inverse gamma conversion and limited gray scale method, respectively. The experimental results show that motion detection can be implemented easily and the detection accuracy is more than 99.3%. The gray scales in moving and static image regions are all expressed smoothly while DFC is markedly improved.     

Structural matching of 2D electrophoresis gels using deformed graphs

2D electrophoresis is a well-known method for protein separation which is extremely useful in the field of proteomics. Each spot in the image represents a protein accumulation and the goal is to perform a differential analysis between pairs of images to study changes in protein content. It is thus necessary to register two images by finding spot correspondences. Although it may seem a simple task, generally, the manual processing of this kind of images is very cumbersome, especially when strong variations between corresponding sets of spots are expected (e.g. strong non-linear deformations and outliers). In order to solve this problem, this paper proposes a new quadratic assignment formulation together with a correspondence estimation algorithm based on graph matching which takes into account the structural information between the detected spots. Each image is represented by a graph and the task is to find a maximum common subgraph. Successful experimental results using real data are presented, including an extensive comparative performance evaluation with ground-truth data.     

基于颜色聚合向量的线序检测方法

颜色聚合向量方法被采用于检测各种连接线的线序。首先对采集到的线束图像进行中值滤波,消除部分噪声;然后截取检测线束的检测区域图像并将其二值化;接下来分割各根导线,得到每根导线的轮廓,再根据各轮廓位置获取原图像中对应各导线的图像块,并计算各根导线图像块的颜色聚合向量（color coherence vector,CCV）特征;最后利用欧氏距离将各导线的归一化的CCV颜色特征和模板各导线的颜色特征进行比较。实验结果表明,该方法在线序检测中能获得较高的准确率（97.8%）和速度（15fps）,满足实时检测要求。     

Using pyramids to define local thresholds for blob detection

A method of detecting blobs in images is described. The method involves building a succession of lower resolution images and looking for spots in these images. A spot in a low resolution image corresponds to a distinguished compact region in a known position in the original image. Further, it is possible to calculate thresholds in the low resolution image, using very simple methods, and to apply those thresholds to the region of the original image corresponding to the spot. Examples are shown in which variations of the technique are applied to several images.     

A robust projector–camera interactive display system based on finger touch control by fusing finger and its shadow

A robust projector–camera interactive display system consisting of one camera and one projector is proposed, which enables users to interact with computer by touching on arbitrary surfaces with bare hand. The system utilizes the camera to recover 3D information of fingertip for touch detection. Firstly, predicted image generated from geometric and photometric calibration matrix is used to segment hand and its shadow. Secondly, fusion degree of the hand and its shadow is detected using linear‐scanning method. Finally, a square tracking mask is used to determine the touch action on the projection surface. Experimental results show that the proposed system is robust to different lighting conditions. The touch detection accuracy is 93.0% and the average processing time of each frame is 36 ms.     

采用圆谐-傅里叶矩的图像区域复制粘贴篡改检测

现有检测方法大多对图像区域复制粘贴篡改的后处理操作鲁棒性不高.针对这种篡改技术,提出一种新的基于圆谐-傅里叶矩的区域篡改检测算法.首先将图像分为重叠的小块;然后提取每个图像块的圆谐-傅里叶矩作为特征向量并对其进行排序;最后根据阈值确定相似块,利用位移矢量阈值去除错误相似块以定位篡改区域.实验结果表明,该算法能有效抵抗噪声、高斯模糊、旋转等图像后处理操作,且与基于HU矩的方法相比有更好的检测结果.     

自适应融合局部和全局稀疏表示的图像显著性检测

针对基于局部或全局稀疏表示的图像显著性检测方法频繁出现提取对象不完整、边界不光滑及噪声消除不干净等问题,提出自适应融合局部和全局稀疏表示的图像显著性检测方法。首先,对原始图像进行分块处理,利用图像块代替像素操作,降低算法复杂度;其次,对分块后的图像进行局部稀疏表示,即：针对每一个图像块,选取其周围的若干图像块生成过完备字典,基于该字典对图像块进行稀疏重构,得到原始图像的初始局部显著图,该显著图能够有效提取显著性目标的边缘信息;接着,对分块后的图像进行全局稀疏表示,与局部稀疏表示过程类似,不同的是针对每一个图像块所生成的字典来源于图像四周边界处的图像块,这样可以得到能有效检测出显著性目标内部区域的初始全局显著图;最后,将初始局部和全局显著图进行自适应融合,生成最终显著图。实验结果表明,提出算法在查准率（precision）、查全率（recall）及F-measure等指标上优于几种经典的图像显著性检测方法。     

大口径光学元件面形检测中重叠激光光斑的分离

在大口径光学元件面形检测系统中,激光光斑的检测及后续处理是基础,直接影响面形检测的精度;针对光学元件面形检测中激光光斑重叠的问题,提出了一种激光光斑重叠分离算法;该算法首先用一种减背景与乘法滤波相结合的方法对光斑图像进行预处理,再用两次阈值法分割图像以获取光斑目标,最后采用距离变换、重叠判别及估算圆心相结合来分离重叠的光斑;实验中,对3种重叠类型不同的光斑进行分离,结果表明,算法能有效地分离重叠的激光光斑;目前,该算法通过长时间的实验验证与改进,已成功运用于实际项目中.     

利用分块相似系数构造感知图像Hash

提出一种基于图像分块相似系数的感知稳健图像Hash.先对图像预处理,再进行重叠分块,在密钥控制下,利用高斯低通滤波器生成伪随机参考图像块,分别计算每个分块与参考图像块的相关系数得到图像特征序列.依此将相邻两个分块特征值合并以缩短Hash长度,同时对压缩后的特征序列进行重排,进一步提高图像Hash的安全性.最后对归一化特征值进行量化,并运用Huffman方法对其编码,进一步压缩Hash长度.理论分析和实验结果表明,该图像Hash方法对JPEG压缩、适度的噪声干扰、水印嵌入、图像缩放以及高斯低通滤波等常见图像处理有较好的鲁棒性,能有效区分不同图像,冲突概率低,可用于图像篡改检测.     

基于超像素的印刷品色差在线检测方法

针对彩色印刷行业中,印刷品色差在线检测准确率低、速度慢的问题,提出一种新的检测方法.基于超像素的思想,采用简单线性迭代聚类(SLIC,simple linear iterative clustering)算法,对具有相似特征的相邻像素进行聚类,形成结构紧凑、近似均匀的像素块,每个像素块即为一个超像素.用超像素代替像素块内多个相似像素,分别提取标准图像和待检测图像的颜色特征.再用CIEDE2000色差公式进行色差计算.实验结果表明,该方法在保证检测结果准确率的基础上,能够有效地减少数据计算量,提高检测效率.     

基于改进Gabor优化选择的布匹瑕疵检测方法

针对传统Gabor优化选择方法用于布匹瑕疵检测时准确率低、鲁棒性差的缺点,提出了改进的优化选择方法,通过瑕疵图像与标准图像Gabor滤波后分块子图均值差平方和的代价函数实现优化选择。设置一组不同方向和尺度的Gabor滤波器并提取标准图像滤波后相关参数,通过改进的优化选择方法实现滤波后瑕疵图像的最优选择,利用迭代式阈值分割对最优滤波后图像进行二值分割,根据分割后图像的像素信息检测是否含有瑕疵并输出瑕疵信息。实验验证该方法,并与传统优化选择方法对比分析,结果表明该方法运算量较少,且检查性能高,可满足在线检测要求。     

卫星遥感技术在永定河流域（河北）土壤侵蚀调查评价中的应用研究

利用Landsat-5TM图像,在分析土壤侵蚀影响因素的基础上,首先进行与土壤侵蚀相关密切的各单项要素的解译;其次,以土壤侵蚀在TM图像上的综合反映为标志进行基本侵蚀图斑的综合解译;第三步通过选定的的土壤侵蚀强度评判模型,对每个基本侵蚀图,由不同权重的各单项要素给出其分值,最后根据综合分值确定每个图斑的土壤侵蚀强度等级。研究结果表明,冀西北地区土壤侵蚀是非常严重的,以轻度侵蚀为下限的侵蚀区面积占全区面积的65％。两大地貌单元区相比,盆地区更严重于山地区。但多时相对比研究也表明,近十几年的治理工作取得了明显成效,土壤蚀的总趋势是向减缓方向发展。     

基于分块特征收缩的行人检测方法

针对基于梯度方向直方图(Histogram of Oriented Gradient,HOG)特征和局部二值模式(Local Binary Patterns,LBP)特征的行人检测存在特征向量维度大、检测精度有待提高的问题,提出了一种分块特征收缩的行人检测方法。首先将样本图像划分成多个大小相同的重叠分块;然后提取各分块的HOG和LBP特征,并将两种特征融合作为分块的特征,通过该特征来训练分块分类器,根据分块分类器的行人检测精度对分块进行排序,选取检测精度较高的分块进行特征收缩;最后将特征收缩后的分块特征向量连接在一起作为最终用于行人检测的特征。在INRIA公共测试集合上的实验结果表明,该方法在降低了特征向量维度的同时提高了行人检测精度。     

Secure video summarization framework for personalized wireless capsule endoscopy

Wireless capsule endoscopy (WCE) has several benefits over traditional endoscopy such as its portability and ease of usage, particularly for remote internet of things (IoT)-assisted healthcare services. During the WCE procedure, a significant amount of redundant video data is generated, the transmission of which to healthcare centers and gastroenterologists securely for analysis is challenging as well as wastage of several resources including energy, memory, computation, and bandwidth. In addition to this, it is inherently difficult and time consuming for gastroenterologists to analyze this huge volume of gastrointestinal video data for desired contents. To surmount these issues, we propose a secure video summarization framework for outdoor patients going through WCE procedure. In the proposed system, keyframes are extracted using a light-weighted video summarization scheme, making it more suitable for WCE. Next, a cryptosystem is presented for security of extracted keyframes based on 2D Zaslavsky chaotic map. Experimental results validate the performance of the proposed cryptosystem in terms of robustness and high-level security compared to other recent image encryption schemes during dissemination of important keyframes to healthcare centers and gastroenterologists for personalized WCE.     

基于DCT变换的脆弱水印技术

提出了一种用于图像鉴定的脆弱水印方法。该方法首先对图像进行8×8分块,计算每一块的DCT值,然后选择所要保护的区域,确定完全属于该区域的分块,并提取这些分块的特定位置的低频分量,采用Hash函数加密生成相应的具有固定长度的数字摘要,然后选取该数字摘要的若干位作为脆弱水印,并把其隐藏到该区域其余的DCT分块中去,以实现水印检测时不需要任何额外信息,试验表明这是一种行之有效的图像鉴别方法。