共查询到19条相似文献,搜索用时 796 毫秒
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本文通过对图象中客体的形心和主轴进行正规化处理而得到其标准线性四元树表示方法。这种表示是客体平移、旋转和相似变化的不变量。它可以用作形状描述符帮助识别图象中的客体。利用对称差的度量匹配某客体的形状到库中一模型来识别它。 相似文献
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针对三维碎片自动拼合中的碎片匹配问题,提出了一种新的轮廓曲线的表示和匹配方法.曲线的表示用带参数的多结点样条插值曲线拟合从碎片物体的轮廓线上提取的数据点,同时计算轮廓曲线上各个点的曲率、挠率和法矢.通过比较不同曲线特征段之间的全曲率,度量轮廓曲线之间的可匹配程度,利用法矢对相似度较高的轮廓曲线进行可匹配性验证,实现三维碎片的匹配.实验结果表明,该算法取得了较好的拟合和匹配效果,为基于轮廓线匹配的物体形状的拼接奠定了基础. 相似文献
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非参数岸岛背景红外舰船目标识别算法研究 总被引:1,自引:0,他引:1
由于战场环境复杂且瞬息万变,针对岸岛背景引入了一种快速
的检测/定位算法。该算法能够搜索出感兴趣的红外舰船目标,比如停靠在港口的舰船,而且无需
预先训练。这种方法仅仅使用一幅单一的目标物体样例图片来发现视场中相似的匹配舰
船,而无需对要搜索的物体进行预先学习。从查询图像中提取局部方向核
作为描述器,用于度量一个像素与其邻域间的相似度。然后从这个描述器中提取出显著
特征,并将其与目标图像中的类似特征进行比较。这些比较是使用一个余弦相似度度量矩阵
来实现的。实验结果表明,这个算法表现优异,成功地识别出了复杂背景条件下的舰船目标。 相似文献
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为了给C语言编程题进行合理评分,本文提出了一种新型的自动评分方法,在动态检测阶段先利用KMP算法执行关键字匹配,若匹配相似度落入预期值区间,则将学生源程序转换为可执行文件,通过预先设置的测试用例来驱动评分;若关键字匹配未通过、程序无法运行或者运行期间出现异常,则执行静态分析.静态分析阶段选取控制结构作为静态评分的关键因素,采用抽象语法树作为源代码的中间转换形式,并对其标准化以消除代码语义的多样性;根据抽象语法树中的结点类型提取出控制结构子树;最后,利用基于结点权值的树编辑距离算法来匹配标准化后的学生源程序与模板程序的控制结构子树,计算相似度并给出综合评分结果.实验结果表明,该方法能够对程序进行合理有效地评分,并且具有较高的准确率. 相似文献
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文中的工作旨在利用人体的独立运动信息,对监控视频中的人群进行计数。首先,检测当前图像中运动物体的角点特征,通过文中的特征可靠性假设,从中选取可靠的角点进行追踪,获得它们的运动轨迹。然后,利用这些特征点的空间信息进行初次聚类,限制最终聚类的数量。最后,利用角点的运动信息定义轨迹相似度和类间相似度,通过构造最小生成树的方法,进行运动一致性聚类,获得最终的特征群,从而得到运动人体的数量。 相似文献
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一种新的基于形状轮廓点分布的图像检索 总被引:1,自引:0,他引:1
用目标轮廓上点的相对位置分布关系对其形状进行描述,基于统计的思想,提出了一种极坐标下形状轮廓点分布特征描述符,不仅符合人眼的视觉感受,而且计算简单;提出了在极坐标下用于度量EMD(earth move′s distance)距离的地面距离计算方法,实验表明,该算法在基于形状的图像分类与检索中取得了良好的效果,而且对目标形状的缩放、平移和旋转等形变具有很好的鲁棒性。 相似文献
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一种新的空间直方图相似性度量方法及其在目标跟踪中的应用 总被引:1,自引:0,他引:1
在基于空间直方图的目标跟踪中,选择一种合适的度量两个空间直方图之间相似性的方法至关重要。该文提出一种新的空间直方图相似性度量方法。将空间直方图中的每个区间所对应像素的空间分布看作一个高斯分布,其均值和协方差矩阵为该区间内所有像素坐标的均值和协方差矩阵,然后用Jensen-Shannon Divergence(JSD)计算对应区间的空间分布相似度,而颜色特征的相似度采用具有强区分能力的直方图相交法来计算。理论和实验证明该文提出的相似性度量的稳定性好,区分能力强,其在静态图像上的整体性能优于已有度量方法,视频跟踪结果比已有方法更精确。 相似文献
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In this paper, we present a new, easy‐to‐generate system that is capable of creating virtual 3D tree models and simulating a variety of growth processes of a tree from a single, real tree image. We not only construct various tree models with the same trunk through our proposed digital image matting method and skeleton‐based abstraction of branches, but we also animate the visual growth of the constructed 3D tree model through usage of the branch age information combined with a scaling factor. To control the simulation of a tree growth process, we consider tree‐growing attributes, such as branching orders, branch width, tree size, and branch self‐bending effect, at the same time. Other invisible branches and leaves are automatically attached to the tree by employing parametric branch libraries under the conventional procedural assumption of structure having a local self‐similarity. Simulations with a real image confirm that our system makes it possible to achieve realistic tree models and growth processes with ease. 相似文献
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Naif Alajlan Mohamed S. Kamel George Freeman 《Signal Processing: Image Communication》2006,21(10):904-918
We aim at developing a geometry-based retrieval system for multi-object images. We model both shape and topology of image objects including holes using a structured representation called curvature tree (CT); the hierarchy of the CT reflects the inclusion relationships between the objects and holes. To facilitate shape-based matching, triangle-area representation (TAR) of each object and hole is stored at the corresponding node in the CT. The similarity between two multi-object images is measured based on the maximum similarity subtree isomorphism (MSSI) between their CTs. For this purpose, we adapt a continuous optimization approach to solve the MSSI problem and a very effective dynamic programming algorithm to measure the similarity between the attributed nodes. Our matching scheme agrees with many recent findings in psychology about the human perception of multi-object images. Experiments on a database of 1500 logos and the MPEG-7 CE-1 database of 1400 shape images have shown the significance of the proposed method. 相似文献
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该文研究了曲面三角网格模型顶点法矢、主曲率和主方向的计算方法,分析了曲面上点的类型,提出了一种基于断裂面匹配的破碎物体拼接方法。分别用曲面上点的有向脚标和无向脚标构成有向特征向量和无向特征向量,在无向特征向量匹配的基础上,经过匹配点方向映射方法判断其它无向特征匹配点对的有向特征向量的相似性,完成断裂面匹配计算。在断裂面匹配的基础上,通过匹配点方向映射实现破碎物体的拼接。实验结果表明该算法可靠地实现了破碎物体的拼接。 相似文献
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Xue-qiang ZOU Peng ZHANG Cai-yun HUANG Zhi-peng CHEN Yong SUN Qing-yun LIU 《通信学报》2016,37(Z1):116-124
Based on the similarity of the layout structure between the phishing sites and real sites,an approach to discover phishing sites was presented.First,the tag with link attribute as a feature was extracted,and then based on the feature,the page tag sequence branch to identify website was extracted,followed by the page layout similarity-HTMLTagAntiPhish,the alignment of page tag sequence tree into the alignment of page tag sequence branches was converted,this converted two-dimention tree structure into one-dimention string structure,and finally through the substitution matrix of bioinfor-matics BLOSUM62 coding,alignment score quickly to improve the phishing sites detection efficiency was computed.A series of simulation experiments show that this approach is feasible and has higher precision and recall rates. 相似文献
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Haris K Efstratiadis SN Maglaveras N Pappas C Gourassas J Louridas G 《IEEE transactions on medical imaging》1999,18(10):1003-1015
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Object segmentation and labeling by learning from examples 总被引:1,自引:0,他引:1
We propose a system that employs low-level image segmentation followed by color and two-dimensional (2-D) shape matching to automatically group those low-level segments into objects based on their similarity to a set of example object templates presented by the user. A hierarchical content tree data structure is used for each database image to store matching combinations of low-level regions as objects. The system automatically initializes the content tree with only "elementary nodes" representing homogeneous low-level regions. The "learning" phase refers to labeling of combinations of low-level regions that have resulted in successful color and/or 2-D shape matches with the example template(s). These combinations are labeled as "object nodes" in the hierarchical content tree. Once learning is performed, the speed of second-time retrieval of learned objects in the database increases significantly. The learning step can be performed off-line provided that example objects are given in the form of user interest profiles. Experimental results are presented to demonstrate the effectiveness of the proposed system with hierarchical content tree representation and learning by color and 2-D shape matching on collections of car and face images. 相似文献
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SAR图像中目标配准的稳健加权核主成分分析方法 总被引:2,自引:2,他引:0
针对震前震后合成孔径雷达(SAR)图像中发生复 杂形变的目标,提 出了基于稳健的加权核主成分分析(KPCA)的配准方法。首先,提出 一种稳健的 加权KPCA(RWKPCA)方法,不仅能获得震前震后形变目标的共同稳健核主成分(RKPC s),还可 以作为异常值判别准则;其次,利用在共同RKPCs上的投影定义震前震后形变目标特 征的相似性度 量;最后,利用特征的相似性度量精确配准形变目标。对2008年5月12日汶川地震前后的S AR图像进行配准并与现有方法进行比较,结果表明,本文方法能够有效的得到形变目标的 共同RKPCs,并得到很好的配准结果。 相似文献