نتایج جستجو برای: pass fourier filtering

تعداد نتایج: 166691  

2011
D. Govind S. R. Mahadeva Prasanna Debadatta Pati

Hilbert envelope (HE) is defined as the magnitude of the analytic signal. This work proposes HE based zero frequency filtering (ZFF) approach for the extraction of epochs in high pass filtered speech. Epochs in speech correspond to instants of significant excitation like glottal closure instants. The ZFF method for epoch extraction is based on the signal energy around the impulse at zero freque...

1997
Javier Portilla Rafael Navarro

We propose a method for efficiently performing space-variant (SV) filtering, which we apply here to the low-pass case. It is based on using a small set of N a priori fixed reference kernels, which are obtained by applying different spatial scaling factors to a mother smoothing filter. The set of 2-D signals obtained by filtering the input image with these kernels is linearly combined to achieve...

Journal: :JDIM 2011
Guoping Zhang Mande Xie

281 ABSTRACT: DDC (Digital Down Converter), as a key part of digital receivers, aims to get low-speed digital baseband signals by extracting and filtering the digital signals transformed by high-speed ADC (Analog Digital Conversion). This paper employs the multi-rate process technique to design the DDC, i.e. firstly conducting data CIC (Cascade Integrator Comb) extraction, then HBF (HalfBand Fi...

2016
S. Muthukumar

The recording of heart signal is called Electrocardiogram (ECG). ECG is used to measure, analyze, observe the heart function and heart abnormalities like cardiac murmur, myocardial infarction etc. The ECG electrodes are sensitive in nature, even the small noise mixed with original signal changes the ECG wave pattern. The ECG signal voltage ranges from 0.5 to 6mV and artifacts can be easily mixe...

2006
David L. Donoho

Image processing researchers commonly assert that “median filtering is better than linear filtering for removing noise in the presence of edges.” Using a straightforward large-n decision-theory framework, this folk-theorem is seen to be false in general. We show that median filtering and linear filtering have similar asymptotic worst-case meansquared error (MSE) when the signal-to-noise ratio (...

2015
LOUKAS GRAFAKOS HANH VAN NGUYEN

We find optimal conditions on m-linear Fourier multipliers to give rise to bounded operators from a product of Hardy spaces Hj , 0 < pj ≤ 1, to Lebesgue spaces Lp. The conditions we obtain are necessary and sufficient for boundedness and are expressed in terms of L2-based Sobolev spaces. Our results extend those obtained in the linear case (m = 1) by Calderón and Torchinsky [1] and in the bilin...

2014
Hanh Van Nguyen

Letm be a positive integer. In this talk, we will introduce optimal conditions,expressed in terms of Sobolev spaces, on m-linear Fourier multiplier operatorsto be bounded from a product of Lebesgue or Hardy spaces to Lebesgue spaces.Our results are sharp and cover the bilinear case (m = 2) obtained by Miyachiand Tomita [1]. References[1] Miyachi A., and Tomita N., Minima...

2014
Hui Li Zhanzhan Zhang

Quantum image recognition is a technology by using quantum algorithm to process the image information. It can obtain better effect than classical algorithm. In this paper, four different quantum algorithms are used in the three stages of palmprint recognition. First, quantum adaptive median filtering algorithm is presented in palmprint filtering processing. Quantum filtering algorithm can get a...

2014
WEI DAI GUOZHEN LU

M. Lacey and C. Thiele proved in [26] (Annals of Math. (1997)) and [27] (Annals of Math. (1999)) that the bilinear Hilbert transform maps L1 × L2 → L boundedly when 1 p1 + 1 p2 = 1 p with 1 < p1, p2 ≤ ∞ and 2 3 < p < ∞. Whether the L estimates hold in the range p ∈ (1/2, 2/3] has remained an open problem since then. In this paper, we prove that the bilinear Hilbert transform does not satisfy an...

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