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After analyzing the speckle model of SAR, a SAR image de-noising method based on Wavelet-Contourlet transform and principal component analysis is presented. Compared with Wavelet transform and Contourlet transform, Wavelet-Contourlet transform can express images more sparsely and obtain image structure better. Most of the existing methods for image de-noising rely on accurate estimation of noise variance...
This article studied the signal reconstruction algorithm of unbalanced vibration signal under strong disturbance background based on weight load balancing principle. Using the precise spectrum analysis method, we can carry out signal reconstruction and obtain the true value of grinding wheel unbalance quantity. Given a kind of unbalanced signal extraction and reconstruction method based on the wavelet...
This article proposes a compound control strategy. It is based on the multi-resolution wavelet controller, the sub-controller and the PID-NNC master-controller and integrated with the WNN wavelet neural network identifier. This strategy can be used to overcome effectively bad influences caused by the system initiation, the control mode, the object change and the exterior disturbance to the regenerative...
In order to denoise image and improve its visual quality, an improved Wiener filtering method is proposed based on wavelet transform. First, image noise is analyzed, and then the image corrupted by noise is given. The noisy image is denoised by the improved Wiener filtering method based on wavelet transform. The procession is repeated until the denoised image satisfied the requirements. Experiment...
This paper proposed a new time-scale representation-"the wavelet spectral correlation function (WSCF)", and analyzed the property and the relation between SCF and WSCF. Based on the analysis of WSCF of fractal stochastic noise and WGN and the SCF of WGN, the property of fractal stochastic noise in the WSC domain is studied. Considering the actual sea clutter, a fractal noise AM-FM model...
The wide sense time-frequency representation based on wavelet was recently proposed, which included the wavelet spectral correlation function (WSCF), wavelet ambiguity function (WAF) and scalograms. The WSC theory was expected to perform effectively in the signal processing involving 1/f noise. Yet despite their apparent importance, the lack of theoretic analysis has, at least until recently, strongly...
Some 2-D signals may have different noise and frequency interference in different directions (horizontal and vertical, or space and time). It is difficult to extract desired signals from such complicated environment of noise and interference by using classical DWT and DCT algorithms. To solve the problem, a hybrid 2-D transform, discrete cosine transform-discrete wavelet (2-D DCT-DWT), with definitions,...
Based on 1-D continuous wavelet transformation (CWT) and 1-D discrete Fourier transformation (DFT), this paper develops 2-D wavelet-Fourier transformation, which can be used to analyze 2-D continuous-discrete signals and systems in wavelet-Fourier hybrid domain. The definitions and properties of this hybrid 2-D transformation are given in the paper. Also, the numerical algorithms of 2-D wavelet-Fourier...
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