scispace - formally typeset
Search or ask a question
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.


Papers
More filters
Journal ArticleDOI
TL;DR: In this article, a new scheme for bearing-localized defect detection based on wavelet transform is presented, which provides a variable resolution time-frequency distribution from which periodic structural ringing due to repetitive force impulses, generated upon the passing of each rolling element over the defect, are detected.
Abstract: This paper presents a new scheme for bearing-localized defect detection based on wavelet transform. Wavelet transform provides a variable resolution time-frequency distribution from which periodic structural ringing due to repetitive force impulses, generated upon the passing of each rolling element over the defect, are detected. In this paper, important properties of wavelet transform and its comparison with short-time Fourier transform are discussed. Then, a basic wavelet considered optimal for bearing-localized defect detection is constructed. Finally, the new scheme is described and its effectiveness is evaluated using actual vibration signals measured from bearings with defects at different locations and operating under different conditions.

187 citations

Journal ArticleDOI
TL;DR: This paper investigates the implementation of the discrete Fourier transform (DFT) in the encrypted domain by using the homomorphic properties of the underlying cryptosystem, and shows that the radix-4 fast Fouriertransform is best suited for an encrypted domain implementation in the proposed scenarios.
Abstract: Signal-processing modules working directly on encrypted data provide an elegant solution to application scenarios where valuable signals must be protected from a malicious processing device. In this paper, we investigate the implementation of the discrete Fourier transform (DFT) in the encrypted domain by using the homomorphic properties of the underlying cryptosystem. Several important issues are considered for the direct DFT: the radix-2 and the radix-4 fast Fourier algorithms, including the error analysis and the maximum size of the sequence that can be transformed. We also provide computational complexity analyses and comparisons. The results show that the radix-4 fast Fourier transform is best suited for an encrypted domain implementation in the proposed scenarios.

186 citations

Journal ArticleDOI
TL;DR: In this paper, a new atomic-parameters least-squares refinement method is presented, which makes use of the fast Fourier transform algorithm at all stages of the computation.
Abstract: A new atomic-parameters least-squares refinement method is presented which makes use of the fast Fourier transform algorithm at all stages of the computation. For large structures, the amount of computation is almost proportional to the size of the structure making it very attractive for large biological structures such as proteins. In addition the method has a radius of convergence of approximately 0.75 A making it applicable at a very early stage of the structure-determination process. The method has been tested on hypothetical as well as real structures. The method has been used to refine the structure of insulin at 1.5 A resolution, barium beauvuricin complex at 1.2 A resolution, and myoglobin at 2 A resolution. Details of the method and brief summaries of its applications are presented in the paper.

185 citations

Journal ArticleDOI
TL;DR: An improved DFRFT is proposed that provides transforms similar to those of the continuous fractional Fourier transform and also retains the rotation properties.
Abstract: The fractional Fourier transform is a useful mathematical operation that generalizes the well-known continuous Fourier transform. Several discrete fractional Fourier transforms (DFRFT's) have been developed, but their results do not match those of the continuous case. We propose a new DFRFT. This improved DFRFT provides transforms similar to those of the continuous fractional Fourier transform and also retains the rotation properties.

185 citations

Journal ArticleDOI
TL;DR: Results prove that, with the proposed methodology, in conjunction with the algorithms proposed by the authors to select optimal mother wavelet and threshold values, significant improvement in denoising effect can be achieved.
Abstract: Recent research has shown that the wavelet transform (WT) can potentially be used to extract partial discharge (PD) pulses from severe noise. However, the method is more complex than the Fourier transform (FT), and requires expertise and experience to be applied to produce its best effect. The authors have previously published algorithms for selection of the most appropriate mother wavelet and for automatic determination of threshold values for applying the WT to PD measurement denoising. The present paper is to present an improved methodology to apply the discrete wavelet transform (DWT) with better denoising effect to PD measurement. Firstly the paper describes the structure of DWT's filter pairs. It then analyses the frequency bands of the wavelet coefficients in approximations and details, and energy distribution of a PD signal along each of the levels following the DWT. Finally a DWT-based denoising method is proposed and justified. Results prove that, with the proposed methodology, in conjunction with the algorithms proposed by the authors to select optimal mother wavelet and threshold values, significant improvement in denoising effect can be achieved.

185 citations


Network Information
Related Topics (5)
Image processing
229.9K papers, 3.5M citations
82% related
Feature extraction
111.8K papers, 2.1M citations
82% related
Image segmentation
79.6K papers, 1.8M citations
81% related
Support vector machine
73.6K papers, 1.7M citations
80% related
Feature (computer vision)
128.2K papers, 1.7M citations
78% related
Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202323
202274
20213
20207
20196
201831