Topic
Harmonic wavelet transform
About: Harmonic wavelet transform is a research topic. Over the lifetime, 9602 publications have been published within this topic receiving 247336 citations.
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TL;DR: In this paper, a joint wavelet decomposition and Fourier transform approach is proposed for the separation of periodic mechanical source signals from a single-channel signal mixture, where the signal mixture is first decomposed to certain wavelet scales and then Fourier transformed to extract the information pertinent to each signal source from these scales.
49 citations
Proceedings Article•
29 Dec 2008TL;DR: Comparisons of various techniques are discussed to analyze the experimental results obtained in MCSA, and it is shown that FFT does not always achieve good results with non-constant load torque.
Abstract: Motor Current Signature Analysis (MCSA) has been successfully used for fault diagnosis in induction machines. The current spectrum of the induction machine for locating characteristic fault frequencies is used in MCSA. The spectrum is obtained using a Fast Fourier Transformation (FFT) that is performed on the signal under analysis. The fault frequencies occur in the motor current spectra are unique for different motor faults. However FFT does not always achieve good results with non-constant load torque. Other signal processing methods, such as Short-time Fourier Transform (STFT) and Wavelet transforms techniques may also be used for analysis. These techniques are capable of revealing aspects of data like trends, breakdown points, discontinuities in higher derivatives, and self-similarity which are not available in FFT analysis. In the present paper, the comparisons of various techniques are discussed to analyze the experimental results obtained.
49 citations
Dissertation•
20 May 2000
TL;DR: The proposed algorithm comprises Fourier-domain system inversion followed by wavelet-domain noise suppression followed by regularized inverse filter, which allows the algorithm to operate even when the inverse system is ill-conditioned or non-invertible.
49 citations
Patent•
16 Sep 1998
TL;DR: In this article, a modified transform method is used to transform the transformed domain image back to the original spatial domain image, which yields spatial domain images that are re-sized versions of the original space domain image.
Abstract: Digital images are represented in the spatial domain by numbers that correspond to pixels and may be transformed to a transform domain image by means of a Transform Method. Other Transform Methods are used to transform the transform domain image back to the original spatial domain image. In this invention, these other Transform Methods are modified in such a way that the Modified Transform Method yields spatial domain images that are re-sized versions of the original spatial domain image. Methods are disclosed for employing the Modified Transform Method to implement zoomed and panned versions of the re-sized images. The re-sized images do not require pixel-level smoothing filters and other methods for removing image distortions due to re-sizing.
49 citations
49 citations