基于Zernike矩的改进LoG边缘检测方法

LoG算子是图像边缘检测中的一种经典方法,其通过引入高斯滤波来减少图像中噪声对边缘检测的影响。高斯滤波在抑制噪声的同时也会将图像的边缘弱化,导致不能有效地对图像边缘进行检测。为此提出了一种改进的LoG边缘检测方法,采用Zernike矩对图像进行结构特征描述,并用其作为LoG算子中高斯滤波权值的计算依据;在此基础上,对平滑图像采用Laplacian算子和零点交叉法检测图像边缘。实验结果显示,通过采用基于Zernike矩的权值计算方法能够有效地保持高斯滤波在平滑图像时弱化的边缘特征,使得LoG算子在抑制噪声的同时能够更加有效地提取图像边缘。     

基于Zernike矩和BP神经网络的纹理分割

提出了一种基于Zernike矩和BP神经网络的纹理分割方法.对图像的每个像素,选择一个窗口,计算该窗口内的Zernkie矩,然后通过非线性变换器将得到的矩值转换成纹理特征;选择BP神经网络作为分类器,将图像的每个像素得到的n维特征向量输入BP神经网络进行分类,最后将结果标注在原图像上.和基于Legendre矩的纹理分割结果相比,基于Zernike矩的纹理分割可以降低分割错误率.     

结合区域合并和水平集的图像分割方法

提出了一种新的图像分割方法.首先利用均值漂移方法对图像进行分割处理,在此基础上进行区域合并得到图像粗分割,然后利用粗分割的结果构造初始水平集函数,利用水平集方法获得图像的最终分割结果.并且针对水平集方法提出了一种新的边缘检测算子,重新定义边缘停止函数,使得对受到噪声影响图像的分割具有鲁棒性.实验结果表明,本方法能有效地提取图像目标,在图像分割质量上具有一定优势,具有较强的实用性.     

基于Arimoto熵和Zernike矩的刀具图像亚像素边缘检测

为满足基于机器视觉的刀具尺寸测量系统快速及高精度的要求,提出一种基于直线截距直方图的Arimoto熵和Zernike矩的图像亚像素边缘检测方法.首先,通过高斯滑动窗口获取图像的邻域平均灰度,构造图像的灰度-邻域平均灰度二维直方图,并利用直线截距法将其降为一维直方图;然后,针对得到的直线截距直方图,依据Arimoto熵准则进行阈值分割,并将所得阈值映射回原二维直方图实现目标区域及像素级边缘的提取;最后,由基于Zernike矩的边缘模型对获取的像素级边缘进行重定位,以完成刀具图像亚像素级边缘的提取.通过对刀具图像进行的大量实验,将文中方法与基于Canny的、基于空间矩的、基于灰度矩的以及基于Zernike矩的边缘提取方法进行对比,发现文中方法运行速度更快且提取精度更高.     

基于视觉的贴片元件检测算法

为了实现贴片元件的自动检测,提出了一种基于视觉的贴片元件几何特征参数检测方法.首先采用最大外接矩形法实现元件的粗定位及确定边缘的分割点,并采用Canny和Zernike矩边缘检测算子实现边缘的精确定位.然后,利用分割点将边缘分割成4部分,分别进行直线和圆弧拟合,得到其精确值.同时,利用快速傅里叶变换后的图像特征,实现端面图像中条纹方向的判定.实验中测得亚像素边缘点的定位精度为0.03像素,直线拟合精度为0.03像素,圆弧拟合精度为0.05像素,端面条纹判断的准确率为100%.实验结果表明:文中提出的检测方法能很好地满足贴片元件自动视觉检测稳定可靠、精度高及实时性强的要求.     

一种快速计算Zernike矩的混合算法

提取傅里叶-梅林矩作为Zernike矩的公共项,将Zernike矩表示为该公共项的线性组.通过研究Zerni-ke核多项式与傅里叶函数的对称性,将图像区域分成8个区域,只以一个区域的Zernike基函数的值代替其他7个区域基函数的值.而且Zernike多项式的系数具有迭代性.综合这3项技术,本文提出了一种快速计算Zernike矩的混合算法.根据对256 bit色灰度图像的实验结果表明该方法明显优于现有方法.     

基于数据场和水平集演化的图像分割

为了充分挖掘图像内不同区域间的隐含关联性,并解决图像分割中自适应阈值选择问题,提出了一种基于数据场和水平集的图像分割方法。利用数据场能够有效地表示图像像素间的相互作用,根据势值能够得到对应的势值等势线,可以根据该等势线的分布情况,采用梯度下降法来得到图像的二值化分割结果。为了得到更为精确的分割边缘,还引入基于拉普拉斯边缘检测函数的水平集演化方法来对二值化结果进行边缘曲线演化。将二值化分割结果与传统的基于数据场的图像分割算法对比结果显示,所提出的算法在分割准确性上表现良好,并且能够使得图像边缘更加精确。实验结果表明,提出的方法能够较好地分割目标,且对噪声图像具有较强的鲁棒性。     

基于 Zernike 矩的边缘检测方法

提出了一种基于Zernike矩的边缘检测方法.根据建立的四参数边缘模型,利用Zernike矩的性质导出了边缘参数和矩的关系,通过求矩得到边缘参数.所提出的方法可以达到子像素级检测精度,对噪声不敏感,具有良好的稳定性.     

结合边缘置信度的自然场景图像分割算法的初探

本文针对基于单个视觉线索传统分割方法的不足,提出了一种结合多种边缘检测信息的自然场景图像区域分割方法。首先,采用边缘检测算子检测出图像的边缘;然后,赋予各个边缘信息一个贡献值,计算出一个综合边缘信息;最后,将综合边缘信息结合均值漂移分割算法对图像进行区域分割。多幅图的目视结果表明:本方法能更有效的抑制过分割和欠分割的产生。     

基于变换域形状描述子的图像检索方法的比较与分析

为了更好地了解变换域方法在图像检索中的检索效果,比较分析了Zernike矩、GFD、PCET、RCFT和RFMT等现有的5种基于变换域的形状描述方法.分别在不变性、计算复杂性、噪声鲁棒性、有效特征数的选取方面对其进行了深入的分析和比较.选用MPEG7 CE Shape-1Part B中的1 400幅图像构成的图像库对这些方法进行检索和性能测试,并实际应用于由500幅病例图构成的图像库的医学图像检索.在研究噪声影响时,对各测试集图片加上不同程度的高斯噪声.通过比较分析及实验结果验证,Zernike矩和GFD方法的检索性能最好,有良好的抗噪性,因而适合于医学图像检索的实际应用.     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the