摄像机标定中特征点的一种自动对应方法

基于计算几何理论中Delaunay三角化原理,提出了一种对具有阵列网络结构的靶标特征点的图像坐标与世界坐标进行自动对应方法.通过对图像处理获取的特征点进行Delaunay三角化预处理,并去除冗余三角形,得到相邻特征点之间的几何连接关系,利用特征点之间的连接关系实现阵列网络结构的靶标特征点的图像坐标与世界坐标的对应.实验...     

Robust multi-view correspondence of noisy 2D points usingrelaxation

An efficient ghost removal algorithm for reliably extracting correspondence information for 2D points from several views using epipolar constraints is proposed. The point matching relations are modelled using a weighted k-partite graph and a globally convergent iterative algorithm is used to extract reliable maximum cliques from the graph using probabilistic relaxation labelling. Experimental results show the effectiveness of the proposed method     

Direct algorithm for rectifying pairs of uncalibrated images

Given the fundamental matrix connecting two uncalibrated images of a 3D scene a convenient procedure is presented for determining transformations to make corresponding points lie on the same horizontal lines. The method is illustrated using two images of a calibration cube, one of many successful applications     

一种双正交消隐点的双目相机标定方法

为了保证双目相机标定精度的同时,提高算法速度。利用田字形模板中的两对正交消隐点,拍摄两幅图像,实现快速标定。首先,提出了消隐点寻优的方法来提取每幅图像中误差最小的两对正交消隐点,线性计算相机主点和归一化焦距,作为内参数的初值。再根据同一幅图像消隐点共线和所有直线畸变后也为直线的原则,构建约束函数,利用优化的差分进化算法进行全局寻优,完成相机畸变校正。最后,根据优化后消隐点坐标求得左右相机的旋转矩阵,并结合左右相机的角点世界坐标,利用刚性变换求得平移向量。双目标定的平均重构误差为0.598pixel,跟传统方法标定误差相当。该标定算法重构误差与传统算法在一个级别,能满足标定中稳定可靠、精度高、抗干扰能力强等要求。     

Representing images using points on image surfaces.

This paper presents a new approach to represent an image by "verge points," which are defined as high-curvature points on the image surface. This representation offers a compact and reversible way to preserve the essence of the original image. Various applications, such as compression, edge detection, image enhancement, and image editing, can be achieved based on this representation. In this paper, the whole procedure for verge point representation is presented. Based on these verge points, image reconstruction can be easily achieved via iterative linear interpolation. These extracted verge points with compatible properties are further linked into verge curves to offer more compact representation. Progressive representation is also developed based on a multiscale extraction scheme. Some potential applications are then presented to demonstrate the versatility of this representation.     

基于电磁特性SAR图像目标识别模板的建立

针对SAR图像目标识别过程中识别模板形成的缺点和难点,提出了基于电磁散射特性SAR图像目标识别模板的数学模型和成像原理。采用一种混合算法计算了复杂目标的雷达截面(RCS),由目标的散射系数σ或RCS值,通过宽带合成孔径原理求出物体散射特性的空间分布,建立了SAR图像目标识别模板。实验验证了其正确性、有效性,以及具有近实时性、目标姿态连续性和精确性等特点,为快速准确地获取SAR图像中的目标信息提供技术支持。     

红外舰船目标的要害点检测算法

针对红外成像与跟踪系统中舰船目标自动识别转跟踪后的跟踪点自动选取问题, 提出了一种新的舰船目标要害点自动检测算法。基于舰船吃水线位于船体位置下方的几何关系以及动力舱的高亮度特征,检测吃水线和动力舱的交叉部位作为首要攻击点,将吃水线中部作为次要攻击点。首先对目标区域进行去噪预处理,通过Canny 边缘提取、边缘闭合、两次连通域去噪等操作滤除背景纹理杂波确定目标的边缘,然后对目标底部边缘进行分段直线拟合,将拟合结果作为吃水线,最后利用灰度值统计确定最亮区域为求取的动力舱位置。实验结果统计表明,该方法检测结果稳定,具有良好的鲁棒性,适用于不同观测方向下的红外舰船目标的要害点检测,为跟踪点的自动选取提供了有效解决方案。     

基于ONU的通信数据传递上行接入控制

利用ONU上行接入算法,防止上行方向数据包的碰撞,给出了一种新的上行授权帧结构,一种改进的动态带宽分配算法.结合了轮询机制和申请的优先级,提高了上行带宽利用率.     

Determining correspondence in 3-D MR brain images using attribute vectors as morphological signatures of voxels

Finding point correspondence in anatomical images is a key step in shape analysis and deformable registration. This paper proposes an automatic correspondence detection algorithm for intramodality MR brain images of different subjects using wavelet-based attribute vectors (WAVs) defined on every image voxel. The attribute vector (AV) is extracted from the wavelet subimages and reflects the image structure in a large neighborhood around the respective voxel in a multiscale fashion. It plays the role of a morphological signature for each voxel, and our goal is, therefore, to make it distinctive of the respective voxel. Correspondence is then determined from similarities of AVs. By incorporating the prior knowledge of the spatial relationship among voxels, the ability of the proposed algorithm to find anatomical correspondence is further improved. Experiments with MR images of human brains show that the algorithm performs similarly to experts, even for complex cortical structures.     

红外舰船要害点定义及其快速实现算法

文中给出了一种舰船目标要害点的定义，即吃水线与动力舱的交叉部位；提出了要害点选择的快速实现算法。实验证明该定义适用于多类型多状态的舰船的目标，算法快速有效，具有很好的鲁棒性。     

基于FPGA的图像多尺度特征点提取及匹配

对于图像的多尺度特征点提取及匹配存在提取特征有限、算法复杂度高、处理速度慢的问题,提出了一种利用多尺度Harris角点方法提取图像中物体边界特征点,采用二维高斯拉普拉斯算子检测图像斑点信号,并基于SIFT特征描绘子计算特征描绘子相似度来完成匹配的方法.该方法充分利用FPGA的并行性特点,通过降低多尺度Harris角点检测、斑点提取和SIFT特征描绘子生成算法的复杂度,在FPGA中实现了图像多尺度特征点的快速提取及匹配.通过对多组图片进行对比测试验证,该方法相对于软件实现方法具有处理速度快,而图像主要特征点不丢失的特点.     

一种基于角点检测方法的骨龄图像关键点定位

在骨龄自动化评定系统的研究中,指骨关键点的定位是其中的一个比较重要的环节,对后续工作研究关系重大。由于指骨关键点是手掌轮廓变化最大的地方,因此把图像中常用的角点检测方法引入到医学图像中,在分析常见的角点检测算法的原理与不足的基础上,提出一种改进的算法来定位指骨关键点。通过实验,并与其它同类方法比较,结果表明,在指骨关键点的精确和快速定位方面,该方法都达到了比较好的效果,可直接应用到骨龄自动评价中。     

Clear correspondence between theoretical and experimental lightpropagation characteristics in photonic crystal waveguides

Single line defect optical waveguides in a photonic crystal airbridge fabricated into a silicon-on-insulator wafer with a minimum propagation loss of 11 dB/mm are demonstrated. The observed propagation loss spectrum and near field patterns at fibre communication wavelengths agree well with those expected from the photonic band calculation     

平顶多高斯光束与平顶高斯光束的一致性研究

对描述平顶光束的两种数学物理模型,即平顶多高斯光束(FMGB)和平顶高斯光束(FGB)作了比较,给出了数值计算结果并作了物理分析。研究表明,具有相同M2因子的两个平顶多高斯光束和平顶高斯光束,无论其束腰宽度是否相等,在广义菲涅耳数相等处都具有相似的光强分布。这一结论对实际工作有应用意义。     

Parameter space warping: shape-based correspondence between morphologically different objects

This paper presents a novel and comprehensive method for the automated determination of correspondences between two morphologically different two-dimensional (2-D) or three-dimensional (3-D) objects. Correspondences are determined by warping parametric representations of the objects to be matched. The warp is guided by the minimization of a similarity criterion function that measures features related to structural correspondence, including Euclidian point-to-point distance and differences in normals and curvature. The method uses a continuous harmonic parameterization for both the object and the warp, which provides: 1) a high degree of computational efficiency; 2) robust extraction of differential features, not subject to discretization errors or noise amplification in differentiation; 3) direct formulation of constraints to avoid overlaps in the resulting correspondence set; and 4) a scale-space paradigm of object shape and warp. The new method does not search for individual landmarks, but operates with a complete, integrated representation of the object geometry. The method was tested on 2-D and 3-D objects with substantial shape differences. Results demonstrated substantial improvements of 2%-33% in correspondence accuracy and 15%-59% in correspondence quality compared with direct registration methods.     

How to compute the difference between tomographic images

An algorithm for estimating the difference between two tomographic images is proposed if the two data vectors are obtained in nonoverlapping time intervals. The algorithm takes advantage of statistical independence of the two vectors. The results are significantly different from the traditional approach in which the two images are reconstructed separately and then subtracted.     

初始段安控图像目标识别方法研究

该研究为实现发射场初始段安控电视系统数字化图像采集、处理和存储展开讨论。采用形态学边缘检测算法、霍夫变换直线检测算法和光流法运动检测算法,利用火箭发射初始段安控电视录像进行测试实验,实现了对发射场初始段火箭箭体的识别。该研究使用数字化图像处理方法对现有的安控电视系统进行有效改进,为安控图像实时判读提供了可靠的依据,并为下一步研究提供了有意义的参考。通过对上述几种之间的特点和处理所需的时间的比较分析,形态学边缘检测算法的效果优于其他两种方法。     

大尺寸三维形貌测量中同名非编码点的精确配准

双目立体视觉测量技术以其测量速度快、精度高、自动化程度高等优势,成为一种有效的大尺寸三维形貌测量实现方法.然而,视觉传感器受到视场的限制,无法通过一次测量获得大尺寸型面的整体形貌,需要通过基于全局控制点的单元数据立体拼接实现.针对大尺寸三维形貌测量系统中全局控制点配准的特点,介绍了一种非编码点的精确配准技术,以满足大尺寸三维形貌测量中不同测站下全局控制点百分之百正确配准的要求.此方法在利用对极几何约束获得粗配准结果的基础上,采用同一测量区域的3幅图像进行二次配准.实验结果表明:基于对极几何约束的粗配准的正确配准率是46.55%,利用3幅图像精配准的正确配准率是98.28%.此方法适用于大尺寸三维形貌测量,能够简单、快速、有效地提高全局控制点的正确匹配率.     

Efficient computation of the Hutchinson metric between digitized images

The Hutchinson metric is a natural measure of the discrepancy between two images for use in fractal image processing. An efficient solution to the problem of computing the Hutchinson metric between two arbitrary digitized images is considered. The technique proposed here, based on the shape of the objects as projected on the digitized screen, can be used as an effective way to establish the error between the original and the, possibly compressed, decoded image. To test the performance of our method, we apply it to compare pairs of fractal objects, as well as to compare real-world images with the corresponding reconstructed ones.