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In general, the main technique to eliminate noise from the signal of partial discharge can be realized in the time and frequency domain. The analysis of the partial discharge signal in frequency and time domain is the basic methodology in signal processing. When the signal is processed in the frequency domain, the time domain information would be lost. To resolve these weaknesses, the wavelet transform...
Wavelet transform is an important tool used in many application areas. This paper proposed the analysis of noise reduction techniques which are based on wavelet transform. In this paper three noise reduction techniques based on wavelet transform are described. These methods are Wavelet Split Coefficient, Hard Thresholding and Soft Thresholding. MATLAB GUI is developed for visualization of results...
ECG signal is time varying in nature which is most common source used for the diagnosis and analysis of heart diseases present in the patient. ECG is recorded by placing electrodes at specified positions of human body. During recording, ECG is contaminated with artifacts and noises which always degrade its quality, and makes accurate and automatic interpretation more difficult. Power line interference,...
The popular existing de-noising methods are compared and analyzed, including wavelet packet decomposition, coefficient shrinkage and modulus maxima method of wavelet transform, which advantages and disadvantages are analyzed and summarized. So their suitable scopes and premise condition are obtained. To accurately analyze high frequency part of signal in submarine tunnel monitoring, the maxima method...
Geochemical data processing plays an important role in the process of geochemical prospecting. According to the nonlinear characteristics of the geochemical data, the wavelet adaptive multi-threshold based on generalized cross-validation (GCV) criterion was adopted towards geochemical data preprocessing and good results are also achieved by validation in practical work area.
Image in the process of collection and storage can produce noise. Wavelet threshold de-noising is a method to remove noise effectively. The threshold function is a key in wavelet threshold de-noising method. In view of the hard-threshold function discontinuity and soft-threshold function deviation problem, through the analysis of the existing wavelet threshold de-noising methods, we present the improvement...
In this article, the characteristics, theories and classification of the threshold de-noising method are introduced in detail. According to the study, when wavelet threshold de-noising method is compared with the wavelet packet threshold de-noising method, the first method is suitable for dealing with the low frequency information, but the second method is available to deal with the information with...
Image de-noising is an important step to improve the AOI (automated optical inspection) image quality of automobile work piece. After analyzing the theory of wavelet transform and the characteristics of traditional soft and hard wavelet threshold de-noising methods, an improved threshold de-noising method was proposed. The new method overcomes the discontinuous in hard threshold de-noising method...
In this paper an approach based on wavelet transform to access the on line Partial Discharge (PD) signal using MATLAB interface with Digital Storage Oscilloscope (DSO) is proposed. The noisy signal is collected and fed to computer through DSO to de-noise this using wavelet threshold technique by selecting the optimal wavelet base. From the results it shows that the de-noising performance is satisfactory,...
In this paper, a new adaptive multi-thretholding image denoising method based on the decomposition order is presented, which is built upon the ideas of Embedded Zero tree Wavelet (EZW) encoder and separate character of signals and noises. This method is not increase in operation amounts but excellent in image denoising results.
The super-resolution approach has attracted substantial attention in the field of image processing in view of its capability of providing higher resolution from low resolution image sequences. Interesting techniques have been developed and practical results have been obtained. However, in several theoretical investigations, good results are often corroborated by simulations, which limits the use of...
Marine radar image often has a lot of noise signal, the noise ratio of the radar image is very low. So a method based on a combination of wavelet transform, K-distributed sea clutter threshold segmentation and most of the interpolation repair method is presented in this paper, which can deal with the same frequency noise of marine radar image. This paper comes up with use wavelet transform to determine...
In this research we scrutinize the face recognition system performance when the test images are imposed to different levels of noise. We tried to imitate the real world scenarios when the face images are captured from video cameras or scanners and suffer some noise. To investigate the performance of proposed system, we simulate this scenario by adding AWGN (additive white Gaussian noise) to the test...
In on-line PD measurement, de-noising Partial Discharge (PD) signal from noisy environment with acceptable performance indices and also with minimum time cost is a major challenge. In this paper a new approach based on wavelet thresholding is proposed for de-noising on-line PD signal. This method first applied on two different type PD signals with White Gaussian Noise (WGN) and simulation results...
This paper deals with image denoising based on the wavelet transform realized by Mallat algorithm and À trous algorithm. The effectiveness of global and subband thresholding techniques are studied on multimedia and astronomical images contaminated by Gaussian noise. Experimental results on several testing images are compared with each other from two objective quality aspects (PSNR, RMSE). Astronomical...
Partial discharge (PD) is the initial sign of power capacitor insulation failure, and an effective extraction and analysis method of PD signal in power capacitor can improve the effectiveness of the on-line fault monitoring. The method which based on wavelet threshold denoising and mathematical morphology alternate mixing filter is put forward in this paper. First, the PD signal which includes noise...
Interpreting a ground penetration radar (GPR) image is an important task in research into subsurface conditions. In a GPR image, noise usually obscures the weak reflections, especially for objects buried at deep locations. The discrete wavelet transform has been recognized as an efficient tool for depressing noise effects appearing in a GPR image. Another approach is the total variation (TV) de-noising...
To the problem of the existing multi-scale edge detection methods couldn't tackle de-noising and edge detail preservation of images, the article proposed a multi-scale edge detection algorithm which took soft threshold method to implement detail enhancement and noise reduction of the true color image. Firstly, obtaining the true color images at different scales through wavelet multi-scale edge detection...
Radom noise attenuation method by contourlet transform is researChed in this paper. Compared with wavelet transform, the contourlet transform proposed by Do and VetterLi offers a high degree of directionaLity and anisotropy, and it represents images sparser. Consequently, contourlet transform can obtain better denoising result than wavelet transform when a simple thresholding sCheme is appLied on...
In this paper, several image denoising methods of protecting edges of images are introduced and the shortcomings of these algorithms are analyzed. A novel high-frequency edge detection method is proposed based on Inter Correlation of Wavelet Coefficients at Finer Scales and the distribution of wavelet coefficients. The experimental results and analysis are given here. The experimental results show...
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