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1.
文章分析传统软、硬阈值函数在图像去噪中的缺陷,提出了一个基于连续阈值函数的小波去噪方法.采用不同阈值函数的去噪方法对图像进行去噪处理,结果表明:基于连续阈值函数的方法的去噪效果优于其他非连续阈值函数的去噪方法.  相似文献   

2.
为了改善小波阈值去噪算法中硬阈值和软阈值存在的不足,提出一种新的小波阈值去噪方法.该算法在进行小波阈值去噪前,先将图像分割成背景平坦区域和细节区域两部分,然后分别进行小波阈值去噪,最后融合两图像从而获得去噪图像.在分别进行小波阈值去噪时,利用迭代法进行阈值选择,采用"软、硬阈值折中"阈值函数.根据对医学图像去噪的仿真实验结果表明,该算法在去噪效果上均优于传统的软硬阈值方法.  相似文献   

3.
基于改进阈值的小波包图像去噪方法研究   总被引:3,自引:0,他引:3  
介绍了小波包分解重构的算法及小波阈值消噪的基本原理,并针对软、硬阈值化方法存在的不足,构造了一个新的阈值化函数,该函数采用两个调节参量α和β,通过调整这两个参数,以获得较优的小波系数的阈值估计.经仿真实验表明,新的小波包阈值化方法能对含噪图像进行有效去噪,且较好地克服了原来软、硬阈值存在的振荡和边界模糊等缺陷.统计结果表明,其性能明显优于原有的软、硬阈值化方法,消噪效果较好.图2,表1,参11.  相似文献   

4.
针对传统的小波阈值函数去噪无法有效滤除信号中的特定噪声,结合软、硬阈值函数的优点,提出了一种基于提升小波新阈值函数算法对心音信号进行去噪.首先利用提升小波变换对心音信号进行分解;然后利用新阈值函数更新其小波系数进行重构;最后与提升小波软、硬阈值函数去噪后的心音进行了希尔伯特包络提取验证其去噪效果.实验结果表明,提出的提升小波去噪新方法较软、硬阈值方法有更好的滤波效果,且提取的曲线包络更加清晰、平滑.  相似文献   

5.
采用双正交小波,利用VisuShrink阈值和BayesShrink阈值,分别通过硬阈值函数和软阈值函数对混入高斯白噪声的图像进行去噪实验.结果表明,硬VisuShrink阈值的降噪效果好于软VisuShrink阈值,软BayesShrink阈值的降噪效果好于硬BayesShrink阈值,并且BayesShrink阈值只有在软阈值函数下才能取得很好的降噪效果.  相似文献   

6.
在对软阈值和硬阈值去噪方法分析的基础上,提出一种改进的阈值函数,并且对阈值做了适当的调整,克服软阈值和硬阈值去噪方法的缺点.Matlab仿真结果表明,提出的改进算法在信噪比增益和最小均方差方面均优于软阈值和硬阈值去噪方法.该改进方案具有更大的有效性和优越性.  相似文献   

7.
针对传统阈值函数在图像去噪中存在的缺点和阈值选取的不确定性,为进一步研究小波去噪处理算法,提出了一种新的改进阈值函数的去噪算法,分别对Circuit、Eight、Road 3幅图像采用传统的硬阈值、软阈值、半软阈值方法和文中方法进行Matlab仿真实验。对比分析,文中方法既获得了较好的视觉效果和更高的峰值信噪比,又克服了软阈值信号失真和硬阈值信号不连续、振荡等缺点,且能够在消噪和保留原有信号的弱特征之间获得较好的平衡,明显地改进了传统硬、软阈值函数去噪算法存在的诸多不足,在实际应用中更为有效。  相似文献   

8.
基于小波变换的一种图像增强去噪算法   总被引:10,自引:1,他引:10  
利用小波变换的自适应特征,将小波的多分辨理论应用于图像的去噪、增强处理中,针对传统的阈值去噪和子带增强的缺点,提出了一种改进的自适应图像去噪增强算法.该算法对图像的噪音进行了估计,采用软阈值和硬阈值相结合的处理方法,利用3次B样条插值函数的特性,设计一个平滑的过渡区,有效地避免了单独使用软阈值或硬阈值处理的缺点,保证了图像达到比较好的去噪效果;同时引入的增益因子,可以自适应地补充图像的弱信息.  相似文献   

9.
图像去噪问题一直是图像处理领域关注的问题之一。在图像去噪过程中,由于软阈值函数获得的去噪估计系数与原小波系数具有的恒定差,进而影响了重建图像的质量。为了有效地解决这一问题,在软阈值函数的基础上,本文提出了一种新的阈值函数用于图像的去噪重建。同时,新提出的阈值函数也有效地解决了硬阈值函数的不连续性问题。为了增加新阈值函数的灵活性,新阈值函数中添加了两个调节因子。实验结果表明,本文的阈值函数优于经典的软、硬阈值函数,有效地解决了软、硬阈值函数存在的缺陷,获得的重建图像质量和峰值信噪比有显著提高。  相似文献   

10.
基于小波收缩的神经网络图像“去噪”算法研究   总被引:1,自引:0,他引:1  
提出一种基于小波收缩的神经网络图像“去噪”的新方法。此算法引入了一种新的小波收缩函数(3次样条曲线)对小波系数进行处理。由于此算法中的小波收缩函数具有较好的光滑特性,它克服了小波收缩中硬阈值和软阈值方法所带来的缺点,并且神经网络模型实现此算法。实验表明:此算法比用传统的硬阈值和软阈值方法图像“去噪”有更好的峰值信噪比且具有比传统算法更好的学习特性。  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.
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   

13.
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   

14.
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   

15.
王慧 《科技信息》2008,(10):240-240
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.  相似文献   

16.
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.  相似文献   

17.
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   

18.
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   

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

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