基于帧缓存的多角度影像精细纹理映射方法

三维建筑物模型纹理映射方法通常针对单独平面选取单一影像投影,然而单张关联影像通常存在部分遮挡问题,影响纹理映射质量. 为此,本文提出一种基于帧缓存纹理绘制技术的多角度影像精准纹理映射方法. 首先将单体化精细建筑模型和倾斜摄影测量解决方案生成的三角网模型配准,再根据建筑模型空间特征进行纹理绘制基元提取;然后根据纹理绘制基元对三角网模型生成虚拟渲染相机,利用帧缓存纹理绘制方法,获取帧缓存对象并提取纹理,最后通过纹理绘制基元映射到精细建筑物模型表面,实现三角网模型到精细单体化建筑模型的自动纹理映射. 利用倾斜摄影测量数据进行实验,实验结果表明,相比传统方法,本文方法减少了14%以上的不良纹理比率,纹理空间压缩率达到14.21%,且具有更精确的纹理映射效果,能满足精细建筑模型的纹理重建需求.      

基于云模糊理论的图像纹理分割

为了处理图像纹理的模糊性和随机性,基于云模糊理论提出了纹理特征矢量云模型,并成功地应用于纹理图像分割.该方法在对纹理统计描述符模糊化处理后,逆向生成纹理特征矢量云.矢量云模型的数字特征能够很好地表达纹理的模糊性和随机性,据此通过云距离计算及纹理特征矢量云生长,完成对图像纹理的分割.实验结果表明,该方法较经典的ISODATA算法和K-means簇算法的分割精度高,并且迭代收敛速度快.     

数字图像技术在露石混凝土路面中的应用

应用数字图像技术,将普通数码相机拍摄的露石水泥混凝土路面照片进行处理,根据图像的灰度值变化分析得到露石混凝土路表面的构造深度,并通过与常规方法的比较表明,此方法测量的路表面构造深度结果可靠,操作简单,可以在分析露石混凝土路面粗糙的表面特征上应用。     

基于数字图像技术的露石混凝土表面构造研究

运用数字图像技术实现了露石混凝土路面(EACCP)图像像素值量化计算,建立了露石表面像素差平均值与构造深度的关系模型;通过采集的数字图像计算分析了露石表面构造深度,评价了EACCP露石表面构造质量。实例分析表明:数字图像技术的露石表面构造检测方法,能方便快捷地进行露石路表构造深度检测,有利于实现测量工作的连续化。     

基于"3S"的大型水上桥梁识别系统

目标识别长期以来一直是图像处理研究的热点之一,在军事和民事方面有重要的应用.文中基于大型桥梁的先验知识,研究了通过水域的纹理特征来检出水域的方法,再应用"3S集成技术",通过数字高程模型(DEM)检出桥梁域,从而提供了对大型水上桥梁识别的一种新方法.     

Automatic Identification of Butterfly Species Based on Gray-Level Co-occurrence Matrix Features of Image Block

In recent years, automatic identification of butterfly species arouses more and more attention in different areas. Because most of their larvae are pests, this research is not only meaningful for the popularization of science but also important to the agricultural production and the environment. Texture as a notable feature is widely used in digital image recognition technology; for describing the texture, an extremely effective method, graylevel co-occurrence matrix(GLCM), has been proposed and used in automatic identification systems. However,according to most of the existing works, GLCM is computed by the whole image, which likely misses some important features in local areas. To solve this problem, this paper presents a new method based on the GLCM features extruded from three image blocks, and a weight-based k-nearest neighbor(KNN) search algorithm used for classifier design. With this method, a butterfly classification system works on ten butterfly species which are hard to identify by shape features. The final identification accuracy is 98%.     

基于数字图像技术的沥青路表面三维构造获取系统

为了客观、真实地评价沥青路表面三维构造,利用数字图像技术研制了一种沥青路表面三维构造获取系统.首先基于经典的漫反射模型the Lambertian Model,获取3张红、蓝、绿二维图像;然后根据光度立体法,利用3张图像的反射光强度计算其x、y方向上的梯度数据;最后借助Frankot-Chellappa全局积分算法将梯度数据进行傅立叶变换,计算得到高度值,实现路表面构造的三维重建.研究结果表明,该系统获取的高度值精度达到0.000 1 mm,满足分析构造深度的要求;与传统方法铺砂法的测试结果相关系数R=0.887 5,相关性较好,证明了该系统应用的可行性.      

基于Gabor变换和灰度梯度共生矩阵的人耳识别研究

人耳识别作为一种新兴的生物特征识别技术,具有其自身独特的优势。提出一种基于Gabor变换和灰度梯度共生矩阵的人耳身份识别方法。首先,利用Gabor变换和灰度-梯度共生矩阵融合提取人耳图像的纹理特征,然后采用K-NN分类器对特征进行分类。该方法用USTB人耳图像库做测试。实验结果表明介绍的提取人耳图像的纹理融合特征的方法优于只采用Ga-bor变换提取特征或是只提取灰度梯度共生矩阵的二次统计特征的性能。在明氏距离测度及K=1时,交叉验证识别率达到81.77%。     

基于MS-RG混合图像分割模型的道路检测研究

道路场景因其结构的多样性、纹理变化的复杂性和自然曝光的不稳定性,使得传统基于道路分割的道路检测方法大多存在信息冗余,并且存在边界丢失、模糊等质量问题.本文首先在道路图像上使用 Meanshift均值漂移算法,通过空间内的概率密度呈梯形上升去寻找局部最优,并搜索属于同一模点的像素然后生成获得超像素块.然后利用 Meanshift算法获得的聚类超像素块进行多种子点区域生长,规范生长规则,克服不能得到封闭边界的缺陷,改进道路图像的分割效果.实验结果表明,本文提出的模型适用性强,相比于传统方法有效地提升了分割准确性和实时性,可准确识别出图像中的道路信息,确保车辆能够行驶在可行驶区域上.     

沥青路面表面纹理三维高精度激光非接触式检测

为实现沥青路面纹理构造高精度自动检测，借助三维激光技术实现路面纹理三维重构，提出模拟铺砂的沥青路面构造深度测量方法. 首先采用高精度三维激光扫描仪获取雅康高速公路沥青路面0.1 mm精度三维高程数据，同时人工铺砂法获取对应区域的宏观构造深度值；其次通过数字图像处理技术实现重构沥青路面三维云图并进行数据噪声处理；最后设计四连通多种子组合填充算法，实现在滤波后的三维路面纹理云图上自动铺砂并获取路面纹理宏观构造深度值. 研究结果表明:模拟铺砂测量方法与人工铺砂法测量的平均构造深度（MTD，M)的平均绝对误差为0.052 mm，两者相关系数为0.96. 研究成果验证了用非接触式路面纹理测试替代现有的接触式路面摩擦性能测试的可行性，为道路交通安全网级监测与管理奠定基础.      

A semi-fragile wavelet transform watermarking scheme for content authentication of images

A novel semi-fragile watermarking scheme for the content authentication of images using wavelet transform (WT) is presented in this paper. It is tolerant to the embedded wavelet image compression methods based on WT such as embedded zerotree wavelet (EZW), set partitioning in hierarchical trees (SPIHT) and embedded block coding with optimized truncation (EBCOT) in JPEG2000 to a pre-determined bit-plane, but is sensitive to all other malicious attacks. The image features are generated from the lowest-frequency (LF) subband of the original image as the embedded watermark. The watermark is embedded into the pre-determined bit-plane by adjusting the corresponding values in the given subband. In the process of watermarking authentication, we compare the image features generated from the LF subband of the received image with the embedded watermarking information (the image features of the original image) extracted from the pre-determined bit-plane in the given subband of the received image to decide whether the image is attacked maliciously or processed acceptably (the embedded wavelet compression). The most important advantage of our watermarking scheme is that the watermark information can be extracted from the watermarked image when detecting watermark, so the received image authentication needs no information about the original image or watermark. Experimental results prove the effectiveness of our proposed watermarking scheme.     

利用窄带信号分类选择宽带声成像信号探讨

讨论了利用现有对窄带信号的分类来选择需要的宽带信号类型的方法.通过对宽带成像模型的分析以及比较宽带模糊函数与窄带模糊函数的联系,指出在一定条件下,按照窄带模糊函数分类的信号其宽带模糊函数具有相似的形状,该方法可用于宽带声成像时对信号的选择,仿真结果表明该方法是一种比较系统的信号设计和选择方案.     

Certificateless strong key-insulated signature without random oracles

It is important to ensure the private key secure in cryptosystem. To reduce the underlying danger caused by the private key leakage, Dodis et al. (2003) introduced the notion of key-insulated security. To handle the private key leakage problems in certificateless signature schemes, we propose a new certificateless strong key-insulated signature scheme. Our scheme has two desirable properties. First, its security can be proved without utilizing the random oracle model. Second, it solves the key escrow problems in identity-based key-insulated signatures (IBKISs).     

基于小波变换在图像去噪中应用

基于噪声是影响图像质量的重要因素.噪声的存在导致图像的某些特征细节不能被辨识,图像信噪比下降.本文将小波阈值去噪与维纳滤波结合起来,在小波域进行维纳滤波.设计了双小波基维纳滤波器,采用两路小波变换,对静态图像和动态影像进行去噪实验,结果表明改进的小波域去噪方法相比其他方法能够获得较好的视觉效果和较高的信噪比.     

Algorithm based on morphological component analysis and scale-invariant feature transform for image registration

In this paper, we proposed a registration method by combining the morphological component analysis (MCA) and scale-invariant feature transform (SIFT) algorithm. This method uses the perception dictionaries, and combines the Basis-Pursuit algorithm and the Total-Variation regularization scheme to extract the cartoon part containing basic geometrical information from the original image, and is stable and unsusceptible to noise interference. Then a smaller number of the distinctive key points will be obtained by using the SIFT algorithm based on the cartoon part of the original image. Matching the key points by the constrained Euclidean distance, we will obtain a more correct and robust matching result. The experimental results show that the geometrical transform parameters inferred by the matched key points based on MCA+SIFT registration method are more exact than the ones based on the direct SIFT algorithm.     

On constructing certificateless proxy signature from certificateless signature

In proxy signature schemes, an original signer A delegates its signing capability to a proxy signer B, in such a way that B can sign message on behalf of A.The recipient of the final message verifies at the same time that B computes the signature and that A has delegated its signing capability to B.Recently many identity-based(ID-based) proxy signature schemes have been proposed, however, the problem of key escrow is inherent in this setting.Certificateless cryptography can overcome the key escrow problem.In this paper, we present a general security model for certificateless proxy signature scheme.Then, we give a method to construct a secure certificateless proxy scheme from a secure certificateless signature scheme, and prove that the security of the construction can be reduced to the security of the original certificateless signature scheme.     

Image Betrayal Checking Based on the Digital Fingerprint of Images on the Internet

In the Internet environment, documents are easily leaked, and divulged files spread rapidly. Therefore, it is important for privacy institutions to actively check the documents on the Internet to find out whether some private files have been leaked. In this paper, we put forward a scheme for active image betrayal checking on the Internet based on the digital fingerprint, which embeds fingerprints into privacy documents, extracts codes from the Internet images, and then finds out the divulged files by matching two groups of codes. Due to so many documents on the Internet, the number of times of code comparison is huge, which leads to a large running time. To overcome the deficiency in practical application, we optimized the process by accurate matching methods and approximate matching method. Then a method was proposed to group objects by locality sensitive hashing (LSH) process before code comparison, in order to eliminate the vast majority of unrelated pairs. Experiments prove that this method could operate with less running time and less memory.     

分层CS-LBP和HOG特征融合的人脸识别研究

针对单独的纹理特征只能提取图像的纹理信息而不能得到图像轮廓边缘信息的问题,在人脸识别的特征提取研究中提出了分层CS-LBP和分层HOG特征的融合方法.对图像分别进行多次CS-LBP和HOG特征的提取,得到分层CS-LBP特征提取图像和分层HOG特征提取图像,对分层的特征提取图像再次提取分层CS-LBP和分层HOG特征,并将两种分层特征进行融合,得到更有效的人脸的纹理及边缘轮廓特征.在ORL和GT人脸库上的实验结果验证了所提出的分层特征融合方法的有效性.     

灰度一梯度共生／环形Gabor滤波纹理分类

解决旋转不变纹理分析问题，提出一种新的旋转不变纹理分类方法：灰度～梯度共生（GGC）／环形Gabor滤波（CGF）联合。将灰度—梯度共生矩阵用于纹理图像的统计分析中。此外，将传统的Gabor滤波器（TGF）改进为环形对称形式，通过CGF信道输出区得旋转不变纹理特征。将两种方法结合起来作为分类纹理依据，提出基于信息增益的特征选择算法。实验结果表明该方法具有较高的分类性能。     

Image fusion scheme based on nonsubsampled contourlet and block-based cosine transform

A kind of nonsubsampled contourlet and block-based cosine transform (NSCBCT) is developed, and its application in image fusion is studied in this paper. The construction of filtering banks is based on the nonsubsampled contourlet transform (NSCT) and block-based discrete cosine transform (B-DCT). We combine NSCT and B-DCT to design filters that lead to NSCBCT with better singularity representation than either of them in isolation. A design framework based on the hybrid approach is proposed, which allows for the fast implementation based on NSCT and B-DCT respectively. In addition, a new image fusion scheme based on NSCBCT for multispectral and panchromatic satellite images is proposed. Firstly, because it adopts NSCT, the fused satellite images have higher spatial resolution than those based on wavelets. Secondly, based on the localized high frequency information provided by B-DCT, the proposed fusion scheme can reduce the spectral distortion of the fused image further. Experimental results show that the proposed fusion method is able to increase the spatial resolution and reduce the spectral distortion of the fused image at the same time.