کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9500320 | 1337608 | 2005 | 9 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Nonlinear wavelet thresholding: A recursive method to determine the optimal denoising threshold
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موضوعات مرتبط
مهندسی و علوم پایه
ریاضیات
آنالیز ریاضی
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چکیده انگلیسی
Nonlinear thresholding of wavelet coefficients is an efficient method for denoising signals with isolated singularities. The quasi-optimal value of the threshold depends on the sample size and on the variance of the noise, which is in many situations unknown. We present a recursive algorithm to estimate the variance of the noise, prove its convergence and investigate its mathematical properties. We show that the limit threshold depends on the probability density function (PDF) of the noisy signal and that it is equal to the theoretical threshold provided that the wavelet representation of the signal is sufficiently sparse. Numerical tests confirm these results and show the competitiveness of the algorithm compared to the median absolute deviation method (MAD) in terms of computational cost for strongly noised signals.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied and Computational Harmonic Analysis - Volume 18, Issue 2, March 2005, Pages 177-185
Journal: Applied and Computational Harmonic Analysis - Volume 18, Issue 2, March 2005, Pages 177-185
نویسندگان
Alexandre Azzalini, Marie Farge, Kai Schneider,