Topic
Quadrature mirror filter
About: Quadrature mirror filter is a research topic. Over the lifetime, 955 publications have been published within this topic receiving 28900 citations.
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31 citations
TL;DR: The e-filter bank proposed in this paper consists of these e-filters and separates the components by taking account of both the signal amplitude and frequency, and a filter system for beautifying facial images using this filter bank is proposed.
Abstract: For the purposes of separating the specific components of nonsteady signals, the e-separating nonlinear filter bank is proposed. Previously, the authors proposed a nonlinear digital filter called the e-filter. This filter effectively eliminates the small signal amplitude random noise superimposed on a signal with a large signal changing component. The e-filter bank proposed in this paper consists of these e-filters and separates the components by taking account of both the signal amplitude and frequency. Further, a filter system for beautifying facial images using this filter bank is proposed. The human facial image consists not only of large-signal components such as the frame, eyes, nose, and mouth, but also of small-signal high-frequency components such as fine wrinkles as well as small-signal medium-frequency components such as large wrinkles and blemishes. Additionally, ultrasmall-amplitude high-frequency components expressing the natural roughness of the skin also exist. The present filter bank can eliminate wrinkles and blemishes while maintaining the natural roughness of the skin, allowing beautification of the skin of facial images to be performed effectively. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 90(4): 52– 62, 2007; Published online in Wiley InterScience (www.interscience. wiley.com). DOI 10.1002/ecjc.20241
31 citations
01 Jan 1972
TL;DR: The proposed theory has been thoroughly simulated and selected experimental results are presented to demonstrate the technique, which can be applied to echoes and overlapping wavelets which might arise in radar, sonar, seismology, or electro-physiology.
Abstract: An algorithm is discussed which decomposes a noisy composite signal of identical but unknown multiple wavelets overlapping in time. The decomposition determines the number of wavelets present, their epochs, amplitudes, and an estimate of the basic wavelet shape. The algorithm is an adaptive decomposition filter which is a combination tion of three separate filters. One is an adaptive cross-correlation filter which resolves the composite signal from noise by an iteration procedure; this is followed by a wavelet extraction filter which ferrets out the basic wavelet form, and last there appears an inverse filter which achieves decomposition of the composite signal in the time domain. The decomposition algorithm can be applied to echoes and overlapping wavelets which might arise in radar, sonar, seismology, or electro-physiology. The proposed theory has been thoroughly simulated and selected experimental results are presented to demonstrate the technique. These include decomposition of brain waves evoked by visual stimulation.
31 citations
Patent•
16 May 1995
TL;DR: In this article, a digital quadrature demodulator for an intermediate frequency (IF) input signal with an analog-to-digital (A/D) converter having a sampling frequency fs and an input to which the IF input signal is applied where the input signal has a band with B
Abstract: A digital quadrature demodulator for an intermediate frequency (IF) input signal with an analog-to-digital (A/D) converter having a sampling frequency fs and an input to which the IF input signal is applied where the IF input signal has a bandwith B
31 citations
TL;DR: A new method based on ABC algorithm for designing two-channel quadrature mirror filter (QMF) banks with linear phase is presented and results are compared with earlier reported results of particle swarm optimization (PSO), differential-evolution (DE) and conventional optimization algorithms.
Abstract: Artificial bee colony (ABC) algorithm has been introduced recently for solving optimization problems. The ABC algorithm is based on intelligent foraging behavior of honeybee swarms and has many advantages over earlier swarm intelligence algorithms. In this work, a new method based on ABC algorithm for designing two-channel quadrature mirror filter (QMF) banks with linear phase is presented. To satisfy the perfect reconstruction condition, low-pass prototype filter coefficients are optimized to minimize an objective function. The objective function is formulated as a weighted sum of four terms, pass-band error, and stop-band residual energy of low-pass analysis filter, square error of the overall transfer function at the quadrature frequency and amplitude distortion of the QMF bank. The design results of the proposed method are compared with earlier reported results of particle swarm optimization (PSO), differential-evolution (DE) and conventional optimization algorithms.
31 citations