to investigate the effect of preprocessing techniques including contrast enhancement and illumination correction on retinal imagequality, a comparative study was carried out. we studied and implemented a few illumination correction and contrast enhancementtechniques on color retinal images to find out the best technique for optimum image enhancement. to compare and choose thebest illumination c...

This work explores aeronautical telemetry communication performance with the SOQPSKTG ARTM waveforms when frequency-selective multipath corrupts received information symbols. A multi-antenna equalization scheme is presented where each antenna’s unique multipath channel is equalized using a pilot-aided optimal linear minimum mean-square error filter. Following independent channel equalization, a...

Loudspeaker equalization is an essential technique in audio system design. A well-known equalization scheme is based on the deconvolution of the desired equalized response with the measured impulse response of the loudspeaker. In this paper, a postprocessing scheme is combined with the deconvolution-based algorithm to provide a better equalization effect. Computer simulation results are given t...

A number of important advances have been made in the area of joint equalization and decoding of data transmitted over intersymbol interference (ISI) channels. Turbo equalization is an iterative approach to this problem, in which a maximum a posteriori probability (MAP) equalizer and a MAP decoder exchange soft information in the form of prior probabilities over the transmitted symbols. A number...

Tufts (1965), Smith (1965), and Berger and Tufts (1967). “Faster than Nyquist” transmission has been studied by Mazo (1975) and Foschini (1984). Channel equalization for digital communications was developed by Lucky (1965, 1966), who focused on linear equalizers that were optimized using the peak distortion criterion. The mean-square-error criterion for optimization of the equalizer coefficient...

Histogram equalization (HE) is widely used for contrast enhancement. However, it tends to change the brightness of an image and hence, not suitable for consumer electronic products, where preserving the original brightness is essential to avoid annoying artifacts. Bi-histogram equalization (BBHE) has been proposed and analyzed mathematically that it can preserve the original brightness to a cer...

ISI (Intersymbol Interference) severely degrades the performance of high speed digital communication systems. A popular technique for countering ISI is Adaptive Equalization. Blind/Unsupervized equalization is one class of adaptive equalization where initial training of equalizer’s weights is not feasible. Godard’s Constant Modulus Algorithm (CMA) was the very first blind equalization algorithm...

A fast implementation of a special non-MSE cost function for blind equalization is presented here. This baud-rate equalization algorithm is based on a convex cost function coupled with a simple linear constraint on the equalizer parameters. For a generic class of channels with persistently exciting quadrature amplitude modulation input signals, this new algorithm allows the convergence of equal...

Blind equalization in noisy multiuser channels has met with increasing attention with the advent of multiaccess digital communication systems. We examine blind equalizer performance in cases where perfect equalization proves unattainable due to noise and interference from concurrent users. In particular, we obtain a characterization of stationary points and extrema for a family of blind criteri...