基于序贯蒙特卡罗的多线索目标跟踪算法

颜色直方图对噪声和部分遮挡不敏感,当背景颜色与目标颜色相近时,会影响跟踪效果.本文提出一种有效的基于多线索融合的序贯蒙特卡罗图像序列跟踪方法,采用颜色直方图和边缘直方图与序贯蒙特卡罗算法结合起采进行视频跟踪.颜色直方图和边缘直方图一起构建目标观测似然函数.在序贯蒙特卡罗方法的框架下,采用观测模型函数获取图像序列中目标位置的后验概率分布.实验结果表明,结合图像颜色与边缘特征,在序贯蒙特卡罗的框架下可以取得更为有效和稳健的跟踪效果.     

基于HSI空间彩色图像多结构元形态边缘检测

构建了一类在HSI 颜色空间基于多结构元彩色形态边缘检测梯度算法实现彩色图像边缘检测新方法,多结构元形态边缘检测有着比单一结构元素形态边缘检测更优越的性能。所定义的算法充分考虑了边缘的方向性和噪声对边缘检测的影响,本算法在噪声抑制方面显示了优良的性能,能满足不同应用的需要。     

基于GVF模型的多目标边缘提取

针对活动轮廓模型的多目标边缘提取问题,本文提出了一种基于GVF模型的改进算法.该算法首先利用GVF模型对整个目标区域进行边缘提取,由于目标间存在滞止点区域,边缘提取的结果中将包含伪边缘.针对这些伪边缘进行分析并设置新的初始轮廓线,再次利用GVF模型进行目标边缘提取,并进行判断.将分别提取到的真实边缘首尾相连,去除伪边缘,可进行多次判断是否存在伪边缘,直至得到完整的多目标边缘.实验结果表明,该改进算法可以实现多目标边缘提取,且易于实现.     

一类基于信息融合的粒子滤波跟踪算法

本文提出了一种基于图像多特征信息融合的粒子滤波跟踪算法.该算法利用颜色柱状图描述运动目标颜色分布信息,帧间差的梯度图像描述目标运动信息,并在柱状图框架下给出了运动目标颜色和运动似然模型,保证了颜色和运动似然模型在尺度上的统一.由于图像多特征提供了运动目标多方面的测量信息,从而提高了算法的可靠性.试验表明该算法在使用相同粒子数目的情况下较采用单一颜色特征的粒子滤波跟踪算法效果好.     

基于背景建模和图像分割的运动目标提取

运动分割是视频分析的重要基础步骤。本文研究了从视频序列中提取运动目标的算法。该算法将自适应背景建模和彩色图像分割相结合而得到具有精确边缘的运动目标。在背景建模中,采用混合高斯模型描述像素点的状态,利用高斯分布特性区分噪声、背景、运动。彩色图像分割运用MeanShift迭代算法对图像进行颜色聚类得到一致的颜色区域。实验结果表明该的算法在固定场景下能够精确分割运动目标。     

基于背景代表色提取的迷彩伪装颜色选取算法

为了达到好的伪装效果,迷彩颜色应与背景色调相融合,以使人眼及光学仪器难以探测和分辨.因此,背景主色的准确提取是确定迷彩颜色的前提.利用灰度直方图可以确定背景图像中的主要灰度,但无法区分不同色调.而基于颜色直方图的背景主色提取方法的运算量太大.本文提出了一种基于HSI模型和量化颜色直方图的迷彩颜色选取算法.利用HSI颜色模型描述背景颜色特性,通过特殊量化方式对背景的颜色直方图进行量化,接着借助阈值方法选取背景主色作为迷彩颜色.结合迷彩伪装图案设计方法对上述迷彩颜色选取算法进行了实验分析,并通过边缘检测和相关跟踪方法对不同背景下的目标迷彩伪装效果进行了验证.     

基于图像边缘的灰度加权算法应用于LED管芯检测

LED管芯检测的像素级算法受到图像分割的影响,造成目标中部分像素的丢失.本文利用图像边缘区域的灰度加权算法,以求取物体边缘所在像素点的灰度来计算边缘位置.检测结果分析表明,该算法在检测精度上有了明显提高.     

基于边缘识别的虹膜定位算法

为了提高虹膜定位算法的抗干扰能力,本文提出了一种基于虹膜边缘识别的虹膜定位算法.该算法应用图像几何矩函数提取虹膜内外边缘的特征,通过由支持向量机(SVM)训练的分类器进行虹膜边缘点的识别.最后由Hough变换对识别的结果进行参数求解并实现虹膜的定位.本算法经过了CASIA虹膜图形库的实验验证,仿真实验数据表明所提算法不仅具有较快的定位速度和较高的定位成功率,而且性能稳定.     

基于Camshift的多特征自适应融合船舶跟踪算法

基于航道内船舶监控图像序列的多目标跟踪技术是开展船撞主动预警,提升桥区船舶通航安全的前提.基于颜色直方图的Camshift跟踪算法在复杂气象条件下无法得到准确的跟踪结果,本文提出了一种多特征自适应融合的多目标跟踪算法.该算法的目标模型由颜色、形状及纹理多特征自适应融合实现,增加了描述目标模型的可靠性和鲁棒性;在跟踪目标...     

基于多特征发现的生理切片骨小梁识别技术研究

目标区域计算机自动识别是骨组织形态计量学的发展趋势。研究图像多特征信息,识别苏木素尹红染色病理切片中的骨小梁。分析骨组织病理切片HSL颜色空间通道的直方图特征,进行基于颜色通道的阈值分割,采用Lazy Snapping算法获得骨小梁深层次特征信息,改进扫描种子填充算法,使其融合目标区域多特征信息。实验结果表明改进的扫描种子填充算法将复杂图像骨小梁提取时间从常规软件的10多分钟提速到257ms。改进的扫描线算法,能快速获得稳健的目标区域。     

Contrast polarity and edge integration in achromatic color perception

Previous work has shown that the achromatic color of a target patch embedded in simple two-dimensional display depends not only on the luminance contrast between the target and its immediate surround but also on the contrasts of other nearby edges. Quantitative models have been proposed in which the target color is modeled as a spatially weighted sum of edge contrasts in which the target edge receives the largest weight. Rudd and Arrington [Vision Res.41, 3649 (2001)] elaborated on this idea to include an additional mechanism whereby effects of individual color-inducing edges are "partially blocked" by edges lying along the path between the inducing edge and the target. We tested the blockage model in appearance matching experiments performed with disk-and-single-ring stimuli having all four possible combinations of inner and outer ring edge contrast polarities. Evidence was obtained for both "blockage" (attenuation) and "antiblockage" (amplification) of achromatic color induction signals, depending on the contrast polarities of the inner and outer ring edges. A neural model is proposed to account for our data on the basis of the contrast gain control occurring between cortical edge detector neurons.     

一种快速虹膜定位算法

针对虹膜内边缘易变形,外边界边缘模糊从而虹膜定位困难等问题,提出了一种快速虹膜定位算法。基于虹膜边缘图像的几何特征,依据偏差平方和定位虹膜内边缘;利用图像灰度曲线得到模糊外边缘的边缘点,根据圆的相交弦性质以及投票策略确定虹膜外边缘的圆心,从而快速定位虹膜外边缘。实验结果表明,该方法提高了虹膜定位的速度以及定位的稳定性,减少了传统虹膜定位算法中搜索的盲目性。     

基于数学形态学的HSI空间彩色边缘检测方法

针对在RGB空间中很难有效区分颜色相似性的问题,选择更加符合颜色视觉特性的HSI颜色空间进行图像处理,提出一种基于HSI空间的多结构多尺度自适应彩色图像边缘检测方法.首先对H、S、I三个分量采用不同结构和不同尺度的结构元素进行形态学边缘检测,然后对三个边缘分量利用信息熵加权得到融合后的彩色边缘信息.实验结果表明,该方法可以充分利用彩色图像的色度,饱和度和亮度信息,有效地抑制噪声,自适应地提取完整的边缘信息.     

纹理贴图模型的彩色截面轮廓生成算法研究

针对彩色3D打印彩色轮廓生成问题,本文提出一种基于纹理贴图模型的彩色轮廓生成算法。根据平面投影法建立纹理和三维模型的映射关系,接着对该模型进行切片处理取得轮廓顶点的几何信息和纹理信息;并根据轮廓顶点和纹理图片的映射关系,插值出顶点间色彩信息;同时给出一种内外轮廓的快速识别算法,并提出一种基于偏置算法的彩色轮廓偏置方法,形成颜色厚度,消除阶梯效应。     

Stevens's brightness law, contrast gain control, and edge integration in achromatic color perception: a unified model

The brightness of an isolated test patch is related to its luminance by a power law having an exponent of about 1/3, a result known as Stevens's brightness law. The brightness law exponent characterizes the rate at which brightness grows with luminance and can thus be thought of as an "exponential" gain factor. We studied changes in this gain factor for incremental and decremental test squares as a function of the size of a surrounding frame of homogeneous luminance. For incremental targets, the gain decreased as an approximately linear function of the frame width. For decremental targets, the gain increased as an approximately linear function of the frame width. We modeled the brightness of the frame-embedded target with a quantitative theory based on the assumption that the target brightness is determined by the sum of achromatic color induction signals originating from the inner and outer edges of the surround, a theory that has previously been used to account for the results of several other brightness matching experiments. To account for the frame-width-dependent gain changes observed in the present study, we elaborate this edge integration theory by proposing the existence of a cortical contrast gain control mechanism by which the gains applied to neural edge detectors are influenced by the responses of other edge detectors responding to the nearby edges.     

可展开天线中索网结构的形态分析与设计

针对可展开天线这一大跨度索梁组合结构体系,提出了一种可以考虑体系中梁单元影响的天线索网结构形态设计方法。该方法将可展开天线中的索网结构划分为具有确定形状要求的内部索网及与刚性外框相连的边界索网两部分。对于内部索网采用平衡矩阵分析法优化计算出索网中各索段的合理预张力值;对于边界索网则通过跟踪其与天线梁单元连接节点在预张力作用下的位置变化来计入天线刚性外框对索网的影响,并通过对形状变化后的索网进行迭代计算来得到各索段的预张力分布值。依据该文方法编制了相应的迭代计算程序,并通过算例分析验证了上述方法的正确性。     

基于图像抽样的快速虹膜定位算法

提出了一种基于图像抽样的快速虹膜定位算法.首先在抽样图像中搜索瞳孔内一点,并以该点为起点检测粗略的虹膜内边缘点,然后在原分辨力图像中利用梯度算子精确定位内边缘点从而实现内边缘定位;虹膜外边缘定位采用Canny算子和Hough变换实现,由于基于抽样图像进行边缘提取,忽略了虹膜纹理等细节边缘信息,减少了大量外边缘干扰,提高了算法实时性.实验结果表明该算法的定位准确率达到99.47%,定位速度为0.162s.与经典的虹膜定位算法相比,该算法的定位速度有了很大提高.     

一种新的彩色图像碎片全自动拼接算法

目的为了实现横向和纵向分切的彩色图像碎片的拼接,提出针对同一张经过横向和纵向分切的彩色图像碎片建立关于相关系数的拼接复原模型和算法。方法通过获取彩色图像碎片的各单色图像,并提取单色图像边缘的灰度值,根据图像碎片边缘灰度值之间的相似程度自动拼接碎片。结果文中算法对彩色图像碎片的拼接效果优于常规算法,实验中采用100张彩色图,对每张彩图分切成64张300×300像素的彩图碎片进行顺序复原,综合拼接成功率达到100%,拼接平均耗时1.59 s。此外,文中算法实验性强,不仅能拼接仅纵切的图像,还能拼接横向和纵向分切的彩色图像。结论实验结果表明该算法对彩色图像碎片的拼接具有很好的适应性和可重复性,对图像碎片的大小和颜色无严格要求,是一套完整有效的针对规则彩色图像碎片的全自动拼接方案。     

Analysis of interactions between shock waves and laminar boundary layers with heat transfer

Summary This paper deals with interactions between shock waves and laminar boundary layers on flat plates with heat transfer. In order to describe this phenomenon the boundary layer is divided into inner viscous layer and outer inviscid layer after Gadd. The boundary layer approximations are assumed to remain valid in the inner layer and the momentum integral equation for the layer is utilized instead of the Pohlhausen's wall condition. In the outer inviscid layer the motion is described by Euler's equation in terms of the isobar coordinates and the deflection angle is determined to match with that at the outer edge of the inner layer. The present theory predicts that self-induced separation does occur for highly cooled wall and yields results in good agreement with the measurement of Lewis et al.With 6 Figures     

Edge‐adaptive color interpolation for complementary color filter array

Complementary color filter array (CCFA) is widely used in consumer‐level digital video cameras, since it not only has high sensitivity and good signal‐to‐noise ratio in low‐light condition but also is compatible with the interlaced scanning used in broadcast systems. However, the full‐color images obtained from CCFA suffer from the color artifacts such as false color and zipper effects. These artifacts can be removed with edge‐adaptive color interpolation (ECI) approaches which are generally used in primary color filter array (PCFA). Unfortunately, the unique array pattern of CCFA makes it difficult that CCFA adopts ECI approaches. Therefore, to apply ECI approaches suitable for CCFA to color interpolation is one of the major issues to reconstruct the full‐color images. In this paper, we propose a new ECI algorithm for CCFA. To estimate an edge direction precisely and enhance the quality of the reconstructed image, a function of spatial variances is used as a weight, and new color conversion matrices are presented for considering various edge directions. Experimental results indicate that the proposed algorithm outperforms the conventional method with respect to both objective and subjective criteria. © 2006 Wiley Periodicals, Inc. Int J Imaging Syst Technol, 16, 92–102, 2006