空间观测图像宇宙线噪声去除算法

空间观测图像容易受到宇宙线噪声的干扰。本文提出一种空间观测图像宇宙线噪声去除算法。首先利用Top-hat变换抑制观测图像的杂散光,处理之后的观测图像背景均匀,直方图的近Gaussian形状得以恢复。然后利用形态学运算和中值滤波相结合的方法排除高亮过饱和恒星的干扰。最后利用Laplacians边缘检测算法检测宇宙线噪声像素,并利用邻域最小值滤波的方法对宇宙线像素的灰度值进行插值处理。实验结果表明,本文方法在不产生误检测的前提下,检测概率超过90%,综合性能优于本文中提到的其它三种宇宙线噪声去除方法。     

Morphological hat-transform scale spaces and their use in pattern classification

In this paper we present a multi-scale method based on mathematical morphology which can successfully be used in pattern classification tasks. A connected operator similar to the morphological hat-transform is defined, and two scale-space representations are built. The most important features are extracted from the scale spaces by unsupervised cluster analysis, and the resulting pattern vectors provide the input of a decision tree classifier. We report classification results obtained using contour features, texture features, and a combination of these. The method has been tested on two large sets, a database of diatom images and a set of images from the Brodatz texture database. For the diatom images, the method is applied twice, once on the curvature of the outline (contour), and once on the grey-scale image itself.     

Laser patterning with beam shaping on indium tin oxide thin films of glass/plastic substrate

In this research the laser beam shaper component has been used to obtain top-hat intensity distribution laser beam to perform line scribing and to perform electrode patterning on Indium thin oxide (ITO) thin films deposited on glass and plastic substrate. ITO films were removed with third harmonic Nd:YAG laser processing system. The pulse duration, laser output power, pulse repetition rate and scanning speed parameters of straight line patterning and electrode patterning on different types of substrates were discussed, respectively. The experimental results are measured by optical microscope and scanning electron microscope to evaluate the processing parameters and surface properties of ITO thin films.     

端面泵浦固体激光棒内温度分布的研究

在分析了端面泵浦、周边冷却的固体激光棒内生热及致冷机制的基础上,将轴对称系统内的热传导问题简化为仅考虑径向热流的一维方程,并推导出“大礼帽”型光束泵浦及高斯光束泵浦两种情况下激光棒内温度分布的表达式。结果表明,在同样的光束尺寸下,利用高斯光束泵浦将导致棒内更加剧烈和更加不均匀的温度变化。文中对讨论进行了无因次处理,以使所获得的结论能够适用于不同的激光材料。     

A pseudo top-hat mathematical morphological approach to edge detection in dark regions

Edge detection is an important pre-processing step in image segmentation. Conventionally, edges are detected according to gradient property, then processed by the thresholding technique. By such an approach, fine edge details in dark region of the image are eliminated. It is annoying sometimes as they are as useful as those in bright region, although this is caused by unevenly distributed lighting in many machine vision applications. In this paper, a novel mathematical morphological edge detection algorithm, based on pseudo top-hat transformation which is derived from top-hat transformation, is proposed to preserve these edge details as well as prominent ones. The algorithm is also presented in detail. Comprehensive experimental results show that the proposed algorithm is efficient for edge details extraction in place of shading while preserving distinguish features.     

计算"Top-hat"端面抽运晶体热透镜焦距的改进方法

在激光二极管(LD)端面抽运的固体激光器中,热效应是设计中必须考虑的重要参量之一。研究激光工作物质内热效应的最方便的方法是等效热透镜(TL)法。前人给出的公式算出的热透镜焦距比实验值小。针对“Top-hat”抽运光,在找出了导致计算值与实验值差距的原因后,给出了能够得出更为精确热透镜焦距值的改进方法,并进行了数值计算,根据计算结果给出了拟合方程。研究结果显示,热透镜焦距不仅仅是抽运功率的函数,还是激光半径与抽运光半径比的函数,并且在激光和抽运光半径大致相当的时候,热透镜焦距大约是原来公式计算值的1.6倍。在相同的抽运条件下,热效应造成的衍射损耗同用原来热透镜焦距计算的结果相比要小很多,同样和激光半径、抽运光半径有关。实验证明新理论比旧理论更接近实验结果。     

车牌定位及倾斜校正方法

提出了一种基于车牌字符信息的车牌定位及其校正方法。首先使用灰度形态学的顶帽操作（top-hat）增强车牌区域,使其能在二值图中突出显示,然后根据二值图中车牌字符的连通元个数和排列位置来确定车牌的具体位置,最后对已定位的车牌进行方向校正,包括水平和垂直方向校正。水平校正是根据这些字符连通元的中心确定车牌的水平倾斜角度,使用旋转几何变换使其水平方向得到校正,垂直校正则使用投影分析的方法求出水平校正后垂直方向的倾斜角度,再进行图像的像素平移。实验结果表明,该方法能够在复杂背景下快速、准确定位到车牌,并且倾斜校正效果很好。     

基于形态学Top-Hat算子和知识处理的目标识别方法

提出了一种基于形态学Top—hat算子和目标形态特征以及空间关系知识处理的目标识别方法。该方法先对SPOT图象进行开Top—Hat和闭Top—Hat运算，以突出目标，抑制背景，然后根据目标固有的形态特征，对目标进行形态滤波．最后利用目标的空间关系特征进行进一步处理，去除虚假目标点。实验表明，该方法对复杂背景的SPOT图象上似圆状目标识别取得了良好的效果。     

基于支持向量机的乳腺钙化点检测算法

针对乳腺X线图像微钙化点检测假阳性高的问题,提出一种微钙化点检测算法.算法首先以小波与Top-hat算子相结合的方法进行钙化点粗检测,然后以支持向量机(SVM:Support Vector Machine)为工具对粗检测结果进行真钙化点与假钙化点分类.对开放乳腺图像数据库MIAS的仿真实验表明,算法的检出率超过98%,错检率不足4%,达到理想的检测效果.     

Top-hat变换在多车牌定位中的应用

为了提高多车牌定位的精度,提出了一种基于Top-hat变换的车牌定位算法。该算法根据车牌纹理的空间分布特点和Top-hat变换的特点,以Top-hat系数为依据,通过平滑、二值化、垂直信息提取、连通、密度计算等多个操作完成车牌定位,该算法可对单、多车牌定位。以实际监控的图像为实验数据,通过对比实验,其结果表明：在不同背景情况下,方法在定位精度、漏判率和误判率等方面均优于其他算法。