Two-dimensional adaptive filters are useful in a wide variety of image and video processing applications. Several different two-dimensional structures and algorithms have been developed, the most recent of which is a ...
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ISBN:
(纸本)0780312813
Two-dimensional adaptive filters are useful in a wide variety of image and video processing applications. Several different two-dimensional structures and algorithms have been developed, the most recent of which is a 2-D IIR adaptive filter. IIR adaptive filters offer reduced computational complexity and increased modeling flexibility when compared to FIR filters. A simple gradient algorithm is developed, and experimental results are presented which clearly show the dependence of convergence on the 2-D indexing scheme. Results show that the 2-D IIR mean-squared-error performance surface characteristics are similar to those of the 1-D IIR adaptive filter with respect to unimodality of the error surface. A quasi-Newton acceleration algorithm is suggested to improve the rate of convergence.
A new direct contrast enhancement algorithm is proposed. It can be used to enhance the contrast of an image without increasing the dynamic range of the pixel values. A distinctive property of the proposed method is th...
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A new direct contrast enhancement algorithm is proposed. It can be used to enhance the contrast of an image without increasing the dynamic range of the pixel values. A distinctive property of the proposed method is that it yields results matching the characteristic of the human visual system. The histogram of the enhanced image has almost the same shape as that of the original image.< >
Conventional adaptive algorithms for image restoration tend to blur the image by smoothing over discontinuities. To overcome this, a discontinuity preserving adaptive algorithm (DPAA) for image restoration is develope...
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Conventional adaptive algorithms for image restoration tend to blur the image by smoothing over discontinuities. To overcome this, a discontinuity preserving adaptive algorithm (DPAA) for image restoration is developed. The basic idea is to combine the continuous line field model with the usual linear finite impulse response (FIR) model used for image restoration. The constructed cost function is minimized using the gradient descent algorithm in adaptive setup. computational cost and simulation results are given to aid comparison of DPAA and the conventional 2-D least mean square (LSD) algorithm.< >
The PC IMega IM-X software packages have been developed under the European Collaborative Programme for training and application in environmental management in less favoured areas. It is a competent imageprocessing to...
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The PC IMega IM-X software packages have been developed under the European Collaborative Programme for training and application in environmental management in less favoured areas. It is a competent imageprocessing tool. GIS modules have been developed for a variety of purposes.< >
Radio wave tomography is a remote sensing technique for imaging a block of rock between two or more boreholes using radio waves. The visualization of the attenuation or slowness [inverse velocity] properties of the ro...
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Radio wave tomography is a remote sensing technique for imaging a block of rock between two or more boreholes using radio waves. The visualization of the attenuation or slowness [inverse velocity] properties of the rock is a signal estimation problem of estimating an image of physical parameters from one-dimensional projection data. The Bayesian paradigm consists of decomposing the posterior signal estimate into a product of prior and likelihood probability distributions. We examine the choice of likelihood distribution on the final signal reconstruction. In particular, Gaussian and exponential likelihood distributions are investigated and their performance is compared for reconstructing an image of rock attenuation from a radio tomography survey conducted in a base metal mine in the northern Cape.< >
In this study, the segmentation of chromosome images is examined. These banded chromosome arms belong to mosquitoes of the anopheles gambiae complex and are stained and mounted on slides. Spurious breaks in the chromo...
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In this study, the segmentation of chromosome images is examined. These banded chromosome arms belong to mosquitoes of the anopheles gambiae complex and are stained and mounted on slides. Spurious breaks in the chromosome arms due to the banded characteristic of the arms, detection of objects which are actually made up of noisy segments of fusion of two or more arms during segmentation due to close proximity of the arms to each other are some of the problems that are encountered during segmentation.< >
In a previous paper, the author presented a multiple exchange algorithm for designing optimal complex Chebyshev finite impulse response (FIR) filters. This algorithm tackles the complex Chebyshev approximation problem...
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ISBN:
(纸本)0780312813
In a previous paper, the author presented a multiple exchange algorithm for designing optimal complex Chebyshev finite impulse response (FIR) filters. This algorithm tackles the complex Chebyshev approximation problem by systematically solving a sequence of subproblems in which each subproblem is defined over a selected set of distinct frequency points. It is pointed out that the approach employed in the previous paper for solving the subproblem, which is based on an efficient implementation of Lawson's algorithm, may encounter numerical difficulties. To alleviate this problem, a new approach which implements Lawson's algorithm with the same computational efficiency as the previous approach while possessing better numerical property is derived.< >
The performance of Hermite wavelets as carriers in a digital subscriber loop (DSL) system is evaluated by means of a computer simulation model. The transmission medium, various types of interference and a nearly compl...
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The performance of Hermite wavelets as carriers in a digital subscriber loop (DSL) system is evaluated by means of a computer simulation model. The transmission medium, various types of interference and a nearly complete implementation of the transmitter and receiver functions are modelled and simulated. Within this simulation framework, a direct comparison is possible between Hermite wavelet multicarrier modulation (MCM) and sinusoidal MCM, allowing a realistic assessment of the advantages and disadvantages of each method.< >
Nonlinear filters have been used in many signalprocessing applications, for example, to obtain optimum signal extraction or detection in the presence of random noise. The weighted median filter (WMF), of which the st...
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Nonlinear filters have been used in many signalprocessing applications, for example, to obtain optimum signal extraction or detection in the presence of random noise. The weighted median filter (WMF), of which the standard median is a special case, is a novel nonlinear technique designed for 2D imageprocessing. A major advantage of the WMF is its flexibility in design to deal with a wide variety of properties. This paper describes a commonly used class W(4,4,1) of the WMF. AS with most nonlinear methods, the computational demands of this technique are high and require a non-trivial number of "expensive" operations. A data parallel approach for efficient implementation of the WMF is described and implemented on two architecturally dissimilar supercomputers, the Convex C3840 and the Connection Machine CM-200. An analysis of the performance obtained from these two high performance parallel platforms is presented.< >
The purpose of this paper is to introduce a new adaptive weighted median (awm) filter that preserves the details of different, textural areas within the image. In the development of the filter, a method is presented b...
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The purpose of this paper is to introduce a new adaptive weighted median (awm) filter that preserves the details of different, textural areas within the image. In the development of the filter, a method is presented based on a Gibbs randoin field (GRF) model of the input and output images. It is shown that this method makes it possible to design and analyze filters with very different characteristics. The proposed awm filter is compared with the standard median filter and the linear averaging filter in noise elimination and detail preservation, and is shown to be significntly better in performance.
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