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.

Fingerprint data acquisition, desmearing, wavelet feature extraction, and identification

Abstract: In this paper, we present (1) a design concept of a fingerprint scanning system that can reject severely blurred inputs for retakes and then de-smear those less blurred prints. The de-smear algorithm is new and is based on the digital filter theory of the lossless QMF (quadrature mirror filter) subband coding. Then, we present (2) a new fingerprint minutia feature extraction methodology which uses a 2D STAR mother wavelet that can efficiently locate the fork feature anywhere on the fingerprints in parallel and is independent of its scale, shift, and rotation. Such a combined system can achieve high data compression to send through a binary facsimile machine that when combined with a tabletop computer can achieve the automatic finger identification systems (AFIS) using today's technology in the office environment. An interim recommendation for the National Crime Information Center is given about how to reduce the crime rate by an upgrade of today's police office technology in the light of the military expertise in ATR.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Method, medium, and system decoding compressed multi-channel signals into 2-channel binaural signals

Abstract: A decoding method, medium, and system decoding an input compressed multi-channel signal, as a mono or stereo signal, into 2-channel binaural signals. Channel signals making up the multi-channel signals may be reconstructed from the input compressed signal in the quadrature mirror filter (QMF) domain, and head related transfer functions (HRTFs) for localizing channel signals in the frequency domain, represented as values in the time domain, may be transformed into spatial parameters in the QMF domain. Accordingly, channel signals may be localized in the QMF domain in directions corresponding to the channels, thereby decoding the input compressed signal as 2-channel binaural signals.

Linear phase FIR biorthogonal wavelet filters with complementarity for image noise reduction

Abstract: In described embodiments, Linear Phase, Finite Impulse Response, filters incorporate a power complementarity property into a perfect reconstruction filter bank. Non-linear constraints for type A and type B filters are included in the Sequential Quadratic Programming design of the filters. An initial Quadrature Mirror Filter includes perfect reconstruction constraints, which might be optimized through iterative design techniques. Embodiments might be employed in noise reduction applications related to, for example, signal processing of images.

Approach to the design of discrete-time wavelets

Abstract: The paper presents an approach to the design of half-band discrete-time wavelets. This is accomplished through the use of a class of quadrature mirror filters which exhibit near- perfect reconstruction property. In particular, we present a technique for the design of such filters, wherein the designer has the flexibility to make tradeoffs between in- band behavior, out-of-band behavior, and the transition-band behavior. The basic formulation is carried out in the frequency domain, which is shown to translate the design problem into an eigenvalue-eigenvector problem. To find the optimal filter for a specific set of specifications, an optimization algorithm is also presented. Using this algorithm, designs ranging from 4 to 80 taps have been carried out successfully. A fairly complete table of resulting filters, which can be used by signal and image processing engineers, is included in the paper.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.