基于双尺度Sech模板的浸润性乳腺癌检测方法研究

乳腺肿块的准确检测是目前计算机辅助诊断系统的关键。为了准确检测X线乳腺图像中的可疑肿块区域,提出一种基于双尺度Sech模板的早期乳腺癌检测方法。首先根据乳腺X线图像的特征对图像进行预处理,包括乳腺区域提取和内外侧斜位图像胸肌提取;然后对提取的乳腺图像进行基于两个不同尺寸的Sech模板的模板匹配,将模板匹配后得到的相似度图像进行融合和阈值截断;最后进行可疑乳腺肿块区域的定位。结果表明,基于双尺度的Sech模板的检测具有更好的检测效果,改善了基于单尺度模板检测准确率低的问题,并降低了假阳率。     

基于灰度直方图的加权模板匹配法在摄像机标定中的应用

采用基于灰度直方图的加权模板匹配法实现摄像机的标定.首先以一个游标卡尺作为目标采集图像,此采集图像作为后续分析的同时用于模板的多处提取;提取的每个模板都将用于后续的模板匹配来提取目标区域(Region of Interest,ROI);匹配所获得的所有目标区域二值化后并旋转90°,以提取其水平方向的灰度直方图;所获得灰度直方图经过优化获得单一峰值后用于获取测量精度;最终标定出的测量精度是由所获得的所有测量精度值进行可信区间的加权平均决定的.本文所采用的加权模板匹配方法不仅降低了单一模板匹配的风险,而且充分利用了具有相似纹理这一有利信息,实验结果表明,提出的方法可以达到工程要求的亚像素级别误差,由此说明该方法在摄像机标定的应用中是行之有效的.     

基于标记控制分水岭算法的乳腺X线摄片分割

乳房区域提取是基于乳腺X线摄片的计算机辅助诊断中的关键步骤。它能够将病灶的检测范围限定在乳房区域之内,减少背景区域的干扰,从而提高诊断效率。针对乳房区域边缘处的灰度与背景区域很接近,难以区分的问题,提出一种基于标记控制分水岭算法的乳房区域分割方法。首先对图像进行形态学平滑并计算梯度图;然后,基于改进的Otsu阈值法及形态学方法确定内部标记和外部标记;最后,在内外标记的控制下对图像进行分水岭分割。采用多种评估方式将算法的分割结果与金标准进行对比,其重叠率达到0.93±0.03,结果表明该算法能有效提高乳房区域分割精度。     

基于框线检测的票据图像分类方法

针对表格型票据,提出了一种基于框线检测的多类别票据图像分类方法.准确提取票据图像的框线特征,根据票据框线的拓扑结构建立起模板库;通过基于框线相关性的相似度模型,与标准模板库中模板的框线特征进行匹配,进而确定票据的分组类别.实际的票据分类实验证实了该方法的有效性和鲁棒性,为票据自动处理打下了坚实的基础.     

利用变形模板提取嘴部特征的算法

嘴部特征提取是人脸识别和人机交互等领域的重要步骤.作者提出了一种改进的利用变形模板提取嘴部特征的算法.针对变形模板对初始位置敏感和匹配易陷于局部极小等问题,首先确定嘴部区域的边框,然后在此区域内仅用边缘和灰度信息,进行全局搜索确定变形模板的最佳参数.算法用两种模板匹配张嘴和闭嘴的情况.实验表明,对于简单背景的灰度图像,该算法可较好地提取嘴部特征,计算速度较快.     

面向辅助驾驶的夜间行人检测方法

辅助驾驶系统需要实时而准确的行人检测方法.文中利用基于知识的方法复杂度小的优点,针对单目远红外视频数据,提出一种基于概率模板匹配的夜间行人检测方法.该方法基于行人样本的灰度分布特征,采用局部双阈值分割算法提取候选目标,进而根据行人的运动方向建立多尺度概率模板,对候选目标进行判别.该概率模板建立方式缓解了行人样本类内方差较大的问题,增强了概率模板归纳行人外观模式的能力.为改善行人检测的准确度,进一步将目标跟踪算法融入概率模板匹配,借助多帧的综合处理结果实现了更为鲁棒的目标归属判断.实验结果表明:该方法计算开销较低,实时性较好;在郊外场景中检测率不低于90%,虚警率不高于10%;而在市区场景中检测率约为75%,虚警率约为22%.     

一种检测宽度的线特征提取方法

线特征提取是计算机视觉及图像处理中的低级处理过程,应用广泛。有关的研究大多数关注于线的位置而忽略了线宽。定义了高斯模板作为局部图像区域,考察区域内灰度值的相似性,通过灰度比较函数获得线响应进行线检测,模板半径与检测到的线宽有着密切的联系。实验结果表明该方法有效地提取了线位置及线宽。     

基于投影直方图提取目标感兴趣区域的新方法

提出了一种基于灰度投影直方图获取单幅检测样品的目标感兴趣区域的方法,并利用鲁棒的图像匹配算法生成参考图像.首先,采用改进的灰度投影直方图法获得单幅图像的检测样品感兴趣区域,建立感兴趣区域提取模型;其次,利用基于形状的特征匹配算法学习样品图像,生成印刷品检测的参考图像,在此基础上,提出基于图像金字塔数据结构的分层匹配方法.实验结果表明,该方法能够在87 ms内获取首张图像样品感兴趣区域,并且图像匹配过程对图像之间存在的明暗程度、旋转变化等干扰具有良好的鲁棒性,匹配精度可达95%,匹配时间为152 ms,可快速准确地生成参考图像.     

基于肤色模型和模板匹配的人脸检测方法研究

提出了一种基于人脸肤色信息和模板匹配,对彩色图像中的人脸进行检测的方法。该方法首先在YCbCr色彩空间下,利用肤色信息将彩色图像中的肤色区域和非肤色区域分开,计算得到表示肤色相似度的色度图,然后分割由此色度图所生成的灰度图像,从而得到人脸检测的候选区域,同时计算该区域的欧拉数来进一步缩小人脸搜索的范围,结合人脸模板进行匹配,最终确定并标记出彩色图像中人脸的位置。实验结果表明:该方法能够在具有复杂背景的彩色图像中快速并且准确的检测出人脸,误检率较低。     

基于特征选择ELM的乳腺肿块检测算法

乳腺肿块检测是防治乳腺癌的有效途径,基于乳腺X射线图像特征模型的极限学习机(ELM)分类算法已被应用于计算机辅助检测乳腺肿块中.针对由于特征间的依赖性导致的ELM学习效率和检测准确度低的问题,提出了基于特征选择ELM的乳腺肿块检测算法.利用影响值选择、序列前向选择和遗传选择等方法进行特征选择,进而利用该结果提高ELM的性能.通过490例来自辽宁省肿瘤医院的乳腺X射线图像的实验表明,基于特征选择ELM的乳腺肿块检测算法能有效提升乳腺肿块检测的效果,其中以遗传选择对ELM性能提升最明显.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

Exciton Seebeck in Molecular Systems

Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with     

Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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An on-line scaling method for improving scalability of a database cluster

The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.     

An improved R-tree based on childnode''s probability

R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).     

Integrating GIS Web services based on mediating architecture

The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.