基于正交T-Snake模型的冠状动脉边缘检测

冠状动脉主干血管边缘的检测可以方便血管相应参数的测量并辅助诊断。该文采用正交网格划分下的T-Snake模型计算边缘曲线。在应用灰度数学形态学方法滤除图像中的大尺度组织噪声与血管内伪边缘后,边缘检测算法根据局部的能量函数值在网格节点上构造并调整边缘曲线,使曲线逼近目标边缘。计算能量函数值时,去掉传统能量函数内部能量中的弹性能量项,并增加面积能量项作为膨胀能量的一部分。临床图像应用结果表明,对于磁共振和X-rayCT造影图像该方法均可实现冠状动脉主干血管边缘的有效检测。     

基于改进的Snake模型的眼细胞彩色图像边缘检测算法研究

在前人研究的Snake模型上提出了适应彩色眼细胞图像边缘检测的改进的Snake模型，该改进模型选取了有益的能量项．舍去了刚性能量项．并在面积能量项的计算上进行了一些改进．在图像力能量项上采用把单通道灰度图像处理方式推广到真彩色RGB三通道的方法．获取彩色图像力能量项．在轮廓初始化时的受控点逆时针排序上给出了行之有效的算法．最后采用贪婪算法最小化总能量．在彩色眼细胞边缘检测上取得了较为明显的效果。     

基于模糊距离变换的三维血管造影冠状动脉形状分析

对血管造影(CTA)数据进行了冠状动脉的形状分析,以辅助临床诊断冠心病。提出了模糊距离变换的三维CTA的冠状动脉的形状分析的方法。利用几何拓扑性获取表面骨架和曲线骨架,计算模糊距离变换函数值,利用此函数值检测冠状动脉的直径、冠状动脉狭窄的位置、长度、狭窄的百分比和冠状动脉的分叉点位置。用仿真数据模型和真实临床数据进行了实验分析和检验。结果表明:此方法准确、省时,能作为临床诊断的有效辅助工具。     

基于图像熵的快速Chan-Vese模型分割算法

提出了基于图像熵的快速Chan-Vese模型分割算法.该算法利用实时图像熵自适应计算模型能量函数中的拟合参数以提高分割速度,并通过检测熵在曲线形变过程中的变化来判定曲线演化的稳定态.实验表明.针对含噪严重、目标模糊且边缘不连续的红外图像目标检测,所提出的分割算法可以取得精确、高效的分割结果.     

基于图像处理的管道泄漏检测与定位

压力曲线上的负压波是管道泄漏的征兆.为快速检测和准确定位压力曲线上的负压波,提出了一种基于图像处理的方法.该方法将压力数值转化为图像灰度值,将压力曲线上的负压波起始点定位等价为图像处理中的边缘检测.利用灰度统计直方图计算一段压力曲线前半段的主流数值,如果压力曲线的后半段偏离主流数值,则表明检测到负压波.对此压力曲线进行灰度拉伸变换,使负压波更为凸显.试验研究表明,该方法可减少系统的误报和漏报,提高定位的精度.     

基于模糊理论的三维无叶扩压器多目标优化

建立了一种基于模糊理论的无叶扩压器优化模型,并采用人机交互的修改单纯形法(IMS)进行求解,模型同时考虑了扩压器的静压升和全压损失.采用计算流体动力学(CFD)方法求解RANS方程得到扩压器的流场分布,从而获得单步优化目标函数值.在采用IMS方法获得新的盖侧曲线后,进行网格重绘,以防止盖侧出现网格线交叉和避免负网格的生成.盖侧曲线采用工程上常用的B样条拟合.优化结果和文献中的结果吻合较好.     

一种具有抗噪声能力的图像清晰度评价函数

针对对焦过程中常用的图像清晰度评价函数对噪声敏感的问题,提出了一种新的清晰度评价函数.利用4方向Scharr算子进行梯度累加计算实现双区域对焦窗口的选择,以减小算法的计算量并提高检测结果的准确性;将对焦窗口进行二维经验模态分解,提取出包含较多图像细节的前2个尺度分量,用以加权计算能量梯度值,得到清晰度评价函数值;为了实...     

造影图像中的心血管边缘提取

提出一种新的造影图像心血管边缘提取方法——最大成本法．通过微分法建立边缘成本空间，利用中心线对血管边缘进行区域划分，采用动态规划理论提取边缘区域内最大成本曲线作为血管边缘．结果表明，该方法具有适用性强，提取边缘连续等特点，有助于造影图像血管直径测量和心血管狭窄病变部位检测．     

基于CV模型改进的磁共振成像图像分割方法

为解决灰度变化缓慢、边缘变化不明显的磁共振成像(magnetic resonance imaging,MRI)图像的分割问题,在CV(Chan-Vese)模型的基础上,改进了CV模型的能量泛函,同时用新的边缘指示函数来替换Dirac函数,优化了CV模型的参数,提高了CV模型的分割精度和分割速度。首先,引入了一个新的局部项。用局部直方图均衡化预处理过的图像与原图像相减得到目标边缘变化较为明显的图像,并将其作为局部项引入到CV模型的能量泛函。然后,由局部项构建新的边缘指示函数。用新构建的边缘指示函数代替Dirac函数,解决了CV模型演化曲线不能检测远离目标的边缘的问题。最后,优化平滑项参数,减少迭代次数提高运行效率。实验结果显示,算法对脑部复发性胶质母细胞瘤的MRI图像具有较好的分割效果。     

融合顶帽和Canny算子的电子束斑图像特征分析

电子束技术在切割和表面融合方面得到了广泛应用.为了更好地检测电子束技术在实际应用中的效果,基于OpenCV对电子束斑图像进行处理分析,提出了电子束斑图像处理算法.该算法融合顶帽和Canny算子进行边缘检测,同时计算得到轮廓的圆度参数与宽度参数,并进行双阈值提取,成功得到清晰的目标轮廓;基于网格计数法提出的电子束斑图像专...     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with