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1.
提出了一种新的基于曲线演化的活动轮廓图像分割模型.该模型利用局部图像统计信息来代替C-V模型中的全局灰度均值,以此可以分割灰度不均匀的图像.此外,在模型定义的能量泛函中增加了水平集正则项,以此来保证数值计算的准确性和避免对水平集函数的重新初始化.将本文提出的活动轮廓模型用于分割人工和自然图像,比较结果显示:C-V模型不能很好处理灰度不均匀图像,而本文提出的模型对灰度不均匀图像能得到满意的分割效果.  相似文献   

2.
针对C-V(Chan-Vese)模型不能较好分割灰度不均匀图像的缺点,对C-V模型能量方程进行改进。将图像的局部灰度拟合信息融入到面积项中,使分割兼顾了图像的全局和局部信息,同时加入惩罚能量项来约束水平集函数逼近符号距离函数,避免模型重新初始化。对灰度不均匀图像分割的实验结果表明,该模型优于C-V模型。  相似文献   

3.
为了提高产品表面缺陷检测精度并降低检测成本,文章以E型磁环表面缺陷的自动检测为例,分析了产品表面图像的特征,提出了一种利用梯度直方图信息的图像自适应阈值分割算法.通过实例,与原自适应直方图阈值分割算法和固定阈值分割算法相比较,结果表明:该算法采用可动态调整的形态学梯度算子计算梯度直方图,抗噪能力强;充分利用了图像的边缘信息和缺陷内部灰度分布不均匀的特性,适应性广;算法简单,具有实时准确分割图像的特点.  相似文献   

4.
针对钢板表面缺陷图像光照不均匀的问题,首先根据图像的亮度与光照分量和反射分量的相关性,采用多尺度高斯函数方法提取图像的光照分量并分离出反射分量.然后根据光照分量的分布情况调整二维(2D)伽玛函数的参数,实现光照分量分布不均的自适应校正,再将校正后的光照分量与原有的反射分量融合得到光照均匀的新图像.最后采用遗传算法选择最大熵阈值进行缺陷分割.结果表明:钢板表面缺陷图像的非均匀光照得到了有效改善,缺陷细节得到了较好保持;图像阈值分割缩短了寻找阈值的时间,能够有效检测出钢板表面的多种缺陷.  相似文献   

5.
针对高铁轮毂表面缺陷实时在线检测问题,提出一种基于视觉显著性注意机制的超像素自适应检测方法。首先采用同态滤波器对缺陷图像进行预处理,去除环境光污染噪声引起的图像亮度分布不均匀问题,构建轮毂表面缺陷图像的谱残差视觉注意模型,之后采用超像素分割算法对缺陷显著性图像进行自适应阈值分割,标记出高铁轮毂表面缺陷的二维空间位置,实现轮毂表面缺陷的边界检测和形态估计。本文方法在高铁轮毂表面缺陷检测实验平台上进行了实验验证,结果表明:该方法能够有效抑制图像分割中的过分割问题,对缺陷的边界信息提取准确,鲁棒性较好。  相似文献   

6.
结合局部与全局信息的主动轮廓模型   总被引:1,自引:0,他引:1  
针对基于主动轮廓模型的图像分割,现有算法不能满足其实际应用多样性的问题,结合LBF模型和C-V模型的优点,提出一个新的结合局部与全局信息的LGIF主动轮廓模型,解决了LBF模型容易陷入局部极小值而导致错误分割的问题,也解决了C-V模型演化速度慢的问题。实验证明,新模型能分割C-V模型、CVI模型不能分割的灰度不均匀的图像,也能分割LBF模型不能分割的灰度不均匀的图像,对初始轮廓的大小和位置不敏感,具有较强的抗噪性。新模型演化速度快,耗时短,效率高,稳定性好。  相似文献   

7.
为了提高乳腺超声图像分割的准确率,提出了一种基于相位特征的C-V模型超声图像分割方法.首先,采用LOG-Gabor滤波器对超声图像进行6个不同方向的滤波,提取最大能量所对应的相位信息,得到超声图像的相位特征.然后,采用SRAD方法对超声图像降噪,并将降噪后的图像与相位特征点乘,增强图像目标与背景的对比度.最后,运用C-V模型的分割算法识别图像中的目标区域,并采用腐蚀方法使目标区域边缘完整、平滑.实验结果表明,与基于灰度的C-V模型、GAC模型以及基于相位特征的人工神经网络方法相比,利用该方法分割乳腺超声图像,分割的精确度明显提高,达到92.40%.  相似文献   

8.
提出了基于图像区域划分和改进C-V法的活动轮廓图像分割方法.通过区域划分的方法将整幅图像的分割问题转化为在不同的子区域上分别进行的图像分割问题,并在各子区域中采用改进C-V法进行图像分割.改进的C-V方法在简化Mum ford-Shah泛函的能量函数中增加距离函数惩罚项,从而将距离函数重新初始化的过程并入整个水平集框架模型中;并在分片常数优化逼近中,添加了图像梯度信息,改变了C-V法中均值取值定义,提高了对灰度层次丰富的图像分割能力.实验表明,该方法对灰度值接近、边界模糊的医学图像有很好的分割效果.  相似文献   

9.
植物根系图像分割是根系构型特征提取和分析的前提.针对传统图像分割方法在处理叶菜根系弱边缘图像中存在分割精度和稳定性较差的问题,提出了一种基于改进C-V(Chan-Vese)模型的变分水平集分割算法.该算法不仅保留了C-V模型对于处理弱边缘图像的适用性,并针对叶菜根系图像局部灰度不均的特点引入了图像梯度信息,改进了原C-V模型.通过对小白菜根系样本图像的分割处理试验,证明了变分水平集分割算法的有效性.研究结果表明,相比传统的阈值处理、边缘检测及区域生长等算法,本文算法能更加精细地解决叶菜根系图像弱边缘和局部灰度不均的问题,并在分割精度和算法稳定性上具有明显的优势.变分水平集算法应用于叶菜根系构型观测系统中,可以有效地提高观测精度.  相似文献   

10.
基于简化的Mumford-Shah水平集图像分割模型,Chan-Vese提出了不依赖于图像边缘的水平集图像分割算法(C-V方法).但是该方法分割参数难以确定,对于具有非均匀灰度背景的红外目标图像常常分割失败.针对这一问题给出了改进的拟合能量模型,新模型兼顾到了目标的同质性信息与其所占面积比例的关系.基于该模型的水平集图像分割方法自适应于灰度起伏的背景,可以较为理想地分割出与背景灰度差异不太明显的目标,对小目标也具有很强的适应性.实验结果表明,在固定水平集分割参数的情况下,新方法对于不同类型、不同背景的红外图像具有了良好的适应性.  相似文献   

11.
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.  相似文献   

12.
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.  相似文献   

13.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

14.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

15.
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。  相似文献   

16.
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.  相似文献   

17.
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.  相似文献   

18.
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。  相似文献   

19.
In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.  相似文献   

20.
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