基于向量内积的新型骨架提取方法

为了提高骨架提取的准确性和连通性,提出了一种基于向量内积的新型骨架提取方法。对二值图像进行欧氏距离变换,获得了由内部像素点指向边界点的边界向量,通过比较内部像素点8-邻域范围内对应边界向量内积值符号在4个方向上的变化情况确定了边界向量方向发生重大变化的次数,并据此选取候选骨架点;采用基于回归分析的方法确定延伸方向,并完成连接操作生成完整的骨架线。实验结果表明,该算法能够保证骨架的连通性和完整性,且骨架定位准确,平均正确率达到92.27%,同时可以克服边界扰动,是一种有效的骨架提取算法。     

基于距离场细化的骨架提取算法

骨架保存了要处理对象的拓扑信息,是图像分析的重要研究内容之一.传统的骨架细化算法不能保证结果的准确性,而距离场的方法无法保证结果的连续性.为此提出一种快速有效的骨架提取算法,将经典的距离变换法和细化方法结合,克服二者之间存在的缺陷,实现算法的互补.经过大量实验验证,此方法能够得到连续、准确的骨架,可以很好地满足实际应用的需求.     

基于骨架的人体识别

本文采用了人体骨架模型的方法,通过距离变换的算法对人体进行了骨架特征提取,同时用腐蚀和还原的算法对骨架的细小分支进行剔除,保留了骨架的主要特征,取得了较好的效果。     

大斜视SAR原始数据的快速模拟算法研究

该文针对小斜视和大斜视模式合成孔径雷达(SAR)提出了两种高效的原始数据模拟算法:变尺度傅里叶变换(SCFT)算法和沿距离向积分算法。基于SCFT的模拟算法将传统的基于2维快速傅里叶变换的2维频域算法推广到斜视模式,采用SCFT取代插值操作,提高了小斜视SAR原始数据模拟的计算效率和仿真精度。沿距离向积分算法适用于大斜视SAR原始数据模拟,保证了大斜视SAR原始数据的模拟精度并同时提高了计算效率。最后,通过仿真证明了这两种算法的有效性。     

一种快速简便的图像骨架变换方法

骨架变换是图像处理的一种重要手段。针对已有的骨架变换方法成编程复杂，或运算速度慢，提出一种快速简便的骨架变换方法。该方法采用起飞—着陆法对二维和三维图像进行距离变换，然后采用局部方向最大值搜索法进行骨架变换。     

一种快速的目标骨架提取算法

提出了一种已知骨架点邻域骨架点的判别准则,首先确定邻域骨架点的大致位置,根据图像离散化的特性在大致位置附近进行骨架点的精确判断,据此可以直接判别初始骨架点邻域的骨架点,以此生成目标的整个骨架结构.同时利用曲线演化与最大圆弦长的方法进行骨架的多尺度控制.算例研究表明:该算法保证了目标骨架的连通性与单像素性,而对骨架的多尺度控制能较好地表示图像中的视觉重要成分,且算法的运算复杂度是骨架点数级的,大大提高了运算速度,为将目标骨架应用于实时目标识别提供了支持.     

一种基于能谱的康普顿散射逐点重建成像方法

利用康普顿散射可以重建物质的电子密度图像。传统的逐点重建法算法简单，但实验装置复杂，且存在对焦误差，文章对传统的逐点重建成像方法进行了改进，提出了基于行扫描散射能谱的逐点重建方法，在此基础上用对称校正的方法对重建结果进行了改善，并给出了计算机仿真的结果。     

基于FPGA的圆弧快速生成算法及其应用

本文设计了一种基于FPGA的圆弧快速生成算法。该算法依靠FPGA强大的计算能力,计算预估圆弧所在区域内各像素点到圆心的距离和到圆弧边界弧度的距离判定该像素是否在圆弧上,从而实现圆弧的快速生成。相较计算机图形学常用的Bresenham圆生成算法和数字微分分析仪算法(digitaldifferentialanalyzer,DDA),本方法消除了圆弧生成过程中逐点递推计算的先后关系,能够充分利用FPGA并行计算的优势,提高圆弧绘制速度。另外通过计算像素到圆弧边界弧度的距离来处理圆弧的两个端点,使圆弧绘制更美观。仿真和实验结果表明:本圆弧生成算法绘制的圆弧视觉效果好,时间效率高,达到了工程应用的目的。     

基于图像森林变换算法的区域增长方法研究

引入了一种基于图的连通性的图像分割算法——图像森林变换算法．通过对其特性的仿真和分析,在目标区域内灰度级变化范围不大的情况下,提出了一种提高执行速度、减少存储空间的IFT新算法,仿真结果证明了该算法的可行性。     

基于Radon变换的昆虫上升下降率提取算法及实验验证

昆虫上升下降率是反映昆虫在迁飞过程中的运动方向与运动速率的重要指标。由于传统垂直昆虫雷达存在距离分辨率低、目标检测关联算法不完善等问题,昆虫上升下降率的提取较为复杂。本文提出一种基于Radon变换的昆虫上升下降率提取算法,该算法通过脉冲多普勒积累与恒虚警检测实现了雷达快时间/慢时间一维距离像矩阵到二值化航迹矩阵的转换,再利用Radon变换从二值化航迹矩阵中实现了昆虫上升下降率的直接提取。通过对实测数据的处理,验证了该算法的可行性。      

Skeletonization for fuzzy degraded character images

Most skeletonization algorithms are operated on binary images. To avoid information loss and distortion, a topography-based approach is proposed to apply directly on fuzzy or gray scale images. A membership function is used to indicate the degree of membership of each ridge point with respect to the skeleton. Significant ridge points are linked to form strokes of skeleton. Experimental results show that our algorithm can reduce deformation of junction points anti correctly extract the whole skeleton, although a character may be broken into pieces. For merged characters, the breaking positions can be located by searching for the saddle points. A multiple context confirmation is used to increase the reliability of breaking hypotheses.     

基于3D体感技术的动态手势识别

提出了一种基于3D体感机Kinect的图像处理手势识别算法,通过深度图像和骨骼图像的方法实现动态手势识别。首先在Kinect提供的骨骼图像中20个骨点中,选取2个离手部最近的骨骼点,通过追踪这两个骨骼点的位置来实现对手部的追踪,再通过判断手部的深度（即其相对于摄像头的距离）的变化来实现动态手势识别。     

A generalized discrete morphological skeleton transform with multiple structuring elements for the extraction of structural shape components

A common problem shared by several leading morphological shape representation algorithms is that there is much overlapping among the representative disks of the same size. A shape component represented by a group of connected disk centers sometimes uses many heavily overlapping representative disks to represent a relatively simple shape part. A shape component may also contain a large number of representative disks that form a complicated structure. We introduce a generalized discrete morphological skeleton transform that uses eight structuring elements to generate skeleton subsets so that no two skeletal points from the same skeleton subset are adjacent to each other. Each skeletal point represents a shape part that is in general an octagon with four pairs of parallel opposing sides. The number of representative points needed to represent a given shape is significantly lower than that in the standard skeleton transform. A collection of shape components needed to build a structural representation is easily derived from the generalized skeleton transform. Each shape component covers a significant area of the given shape and severe overlapping is avoided. The given shape can also be accurately approximated using a small number of shape components.     

结合区域生长及主成分分析的机载LiDAR建筑物点云提取

针对机载LiDAR建筑物点云提取过程中与树木紧邻的建筑物难以提取,已有先滤波后提取算法效率低等问题,提出一种结合区域生长与主成分分析的机载LiDAR建筑物点云提取算法。该算法首先对粗差剔除后的机载LiDAR离散点云构建TIN三角网,依据建筑物边缘点所在三角形的特征提取建筑物边缘点;然后将邻域特征优化后的建筑物边缘点作为种子点进行区域生长得到建筑物点云;最后采用主成分分析对提取结果进行检核,剔除非建筑物点云,在此基础上基于连通性对建筑物点云进行单体化分割,剔除小面积区域,得到最终的建筑物激光脚点数据。实验选取国际摄影测量与遥感协会提供的三组典型区域的LiDAR点云数据进行建筑物提取,并与传统形态学和区域生长两种建筑物点云提取算法进行比较,结果表明本文算法可以实现建筑物点云的高精度提取,且对地形及不同类型屋顶的建筑物具有良好的自适应性,验证了算法的可靠性。      

An efficient rate-distortion optimal shape coding approach utilizing a skeleton-based decomposition

In this paper, we present a new shape-coding approach, which decouples the shape information into two independent signal data sets; the skeleton and the boundary distance from the skeleton. The major benefit of this approach is that it allows for a more flexible tradeoff between approximation error and bit budget. Curves of arbitrary order can be utilized for approximating both the skeleton and distance signals. For a given bit budget for a video frame, we solve the problem of choosing the number and location of the control points for all skeleton and distance signals of all boundaries within a frame, so that the overall distortion is minimized. An operational rate-distortion (ORD) optimal approach using Lagrangian relaxation and a four-dimensional direct acyclic graph (DAG) shortest path algorithm is developed for solving the problem. To reduce the computational complexity from O(N/sup 5/) to O(N/sup 3/), where N is the number of admissible control points for a skeleton, a suboptimal greedy-trellis search algorithm is proposed and compared with the optimal algorithm. In addition, an even more efficient algorithm with computational complexity O(N/sup 2/) that finds an ORD optimal solution using a relaxed distortion criterion is also proposed and compared with the optimal solution. Experimental results demonstrate that our proposed approaches outperform existing ORD optimal approaches, which do not follow the same decomposition of the source data.     

Propagation of double-exponential pulse through Debye medium

The saddle point method is applied to the problem of signal propagation through Debye medium. The steepest descent method is used to calculate the propagation of a double-exponential pulse through Debye medium, and the results are compared with those obtained through Hosono's (1980) method and finite-difference time-domain (FDTD) method. It is found that a Gaussian function can be used to approximate the propagated signal for sufficiently long propagation distance and the analytical representations for the amplitude, center, and width of the propagated pulse are obtained based on the first-order asymptotic representation. An analytical approximation of the saddle points valid for late time is also obtained     

基于广义势场的肝脏管道骨架可视化方法研究

为了使复杂的肝脏血管管道结构易于重建及分析,提出了一种基于广义势场的三维骨架化方法。通过构建斥力场源计算三维势场值,检测矢量场的关键点,从而得到血管管道的核骨架,再利用OpenGL进行可视化。结果表明,该方法所提取的骨架具有较好的光滑性、单体素宽和连通性,对后续的肝脏管道数学模型建立、肝脏管道形态结构的三维重建具有一定的指导意义。