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221.
222.
小波变换用于二次微分交流示波计时电位信号中有用信息的提取 总被引:14,自引:4,他引:14
小波分析是80年代发展起来的一种新的数学分支。由于小波变换具有许多其它的信号处理手段所不具备的优良特性,如正交性,可变的时-频分辨率和可调节的局部支持等,使它成为信号处理的一种强有力的工具。 相似文献
223.
小波分析在分析信号处理中具有诸多显著的优点。本文介绍了小波分析的一般描述,综述了化学计量学在的小波新方法,并展望了小波分析在分析化学计量学中的应用前景。 相似文献
224.
225.
Lili Zang 《Numerical Functional Analysis & Optimization》2013,34(9):1090-1101
One of the fundamental problems in the study of wavelet frames is to find conditions on the wavelet function and the dilation and translation parameters so that the corresponding wavelet system forms a frame. In this article, we obtain some inequalities for a discrete wavelet system to be a frame. Our result improves known ones by Chui, Shi, and Chen. 相似文献
226.
In this article, Haar wavelets have been employed to obtain solutions of boundary value problems for linear fractional partial differential equations. The differential equations are reduced to Sylvester matrix equations. The algorithm is novel in the sense that it effectively incorporates the aperiodic boundary conditions. Several examples with numerical simulations are provided to illustrate the simplicity and effectiveness of the method. 相似文献
227.
A new contrast enhancement algorithm for image is proposed combining genetic algorithm (GA) with wavelet neural network (WNN).
In-complete Beta transform (IBT) is used to obtain non-linear gray transform curve so as to enhance global contrast for an
image. GA determines optimal gray transform parameters. In order to avoid the expensive time for traditional contrast enhancement
algorithms, which search optimal gray transform parameters in the whole parameters space, based on gray distribution of an
image, a classification criterion is proposed. Contrast type for original image is determined by the new criterion. Parameters
space is, respectively, determined according to different contrast types, which greatly shrink parameters space. Thus searching
direction of GA is guided by the new parameter space. Considering the drawback of traditional histogram equalization that
it reduces the information and enlarges noise and background blur in the processed image, a synthetic objective function is
used as fitness function of GA combining peak signal-noise-ratio (PSNR) and information entropy. In order to calculate IBT
in the whole image, WNN is used to approximate the IBT. In order to enhance the local contrast for image, discrete stationary
wavelet transform (DSWT) is used to enhance detail in an image. Having implemented DSWT to an image, detail is enhanced by
a non-linear operator in three high frequency sub-bands. The coefficients in the low frequency sub-bands are set as zero.
Final enhanced image is obtained by adding the global enhanced image with the local enhanced image. Experimental results show
that the new algorithm is able to well enhance the global and local contrast for image while keeping the noise and background
blur from being greatly enlarged. 相似文献
228.
Chun‐Sheng Yin Wei‐Min Guo Shu‐Shen Liu Yang Shen Zhong‐Xiao Pan Lian‐Sheng Wang 《中国化学》2001,19(9):836-841
A simultaneous determination of four components of B‐group vitamin, using a novel wavelet‐based neural network (WNN), combined with correlation coefficient and standard deviation approach for wavelength selection, was reported in this work. Eleven representative wavelength points were selected from each original UV spectrum, based on correlation coefficients and standard deviations of the observed data. A family of wavelet basic functions built from Morlet wavelet was adopted to improve the transfer quality of output data and solve the problems of training difficultly involved in neural networks. The predicted results, with fitting correlation coefficients (R = 0.9998–0.9999) and rooted mean squares errors (RMS = 0.0578–0.1478), are satisfactory. 相似文献
229.
本文研究了线性模型中的一种有偏估计,利用均方误差和残差平方和,得到了岭型主相关估计的一些性质,是对[1]中相关结果的推广. 相似文献
230.
This paper presents a stationary wavelet transform (SWT) method for speckle noise reduction in digital speckle pattern interferometry fringes. The main advantage of SWT is its translation invariance, which makes it important in statistical image processing applications. This method was used to denoise a simulated speckle fringe patterns, a good fidelity value was obtained. Applied to the wavelet phase evaluation, it has provided a phase distribution with a good accuracy. 相似文献