Accurate extraction of retinal blood vessels is an important task in computer aided diagnosis of retinopathy. The matched filter (MF) is a simple yet effective method for vessel extraction. However, a MF will respond not only to vessels but also to non-vessel edges. This will lead to frequent false vessel detection. In this paper we propose a novel extension of the MF approach, namely the MF-FD...

Spectrum sensing techniques are envisaged to solve the problems in wireless networks resulting from the limited available spectrum and the inefficiency in the spectrum usage. In this paper various Spectrum Sensing Techniques like Energy Detection, Matched Filter, Cyclo-stationary Detection, Wavelet Detection are compared. The best one is evaluated for its performance. Then Cooperative Spectrum ...

This paper presents a low-power structure of digital matched filters (DMFs), which is proposed for direct sequence spread spectrum systems. Traditionally, low-power approaches for DMFs are based on either the transposedform structure or the direct-form one. A new hybrid structure that employs the direct-form structure for local addition and the transposed-form structure for global addition is u...

The propagation of waves through a doubly-periodic array of identical rigid scatterers is considered in the case that the field equation is the two-dimensional Helmholtz equation. The method of matched asymptotic expansions is used to obtain the dispersion relation corresponding to wave propagation through an array of scatterers of arbitrary shape that are each small relative to both the wave l...

We show that a biorthogonal spline wavelet closely approximates the prewhitening matched filter for detecting Gaussian objects in Markov noise. The filterbank implementation of the wavelet transform acts as a hierarchy of such detectors operating at discrete object scales. If the object to be detected is Gaussian and its scale happens to coincide with one of those computed by the wavelet transf...

The first kilometer-scale gravitational wave observatories, LIGO [1] and VIRGO [2], are expected to begin performing searches for astrophysical sources of gravitational waves in the year 2002. By this time, it will be necessary to have data analysis software for on-line searches. Because the anticipated signals are expected to be weak, near-optimal strategies for data analysis will be required ...

Gaussian filter has been used extensively in signal image processing for many years. Gaussian or Gaussian derivative filtering is in several ways optimal for applications requiring low-pass filters or running averages. In this paper, a highly efficient noise removing technique based on a modified dynamic Gaussian filter is introduced. Called smooth filter, the Gaussian filter is known to be mor...