Proceedings ArticleDOI
Robust detection of object boundaries in Weibull radar imagery
Robin A. Brooks,Alan C. Bovik +1 more
- pp 1256-1259
TLDR
The efficacies of edge detectors defined as ratios of single order statistics, ratios of averages and ratios of best linear unbiased estimators (BLUEs) are compared and are based on computed error probabilities as the Weibull parameters are varied.Abstract:
Radar image speckle is often modeled as having a negative-exponential, or more generally, gamma distribution. However, studies of noise in coherent radar systems suggest that the first-order statistics may be more accurately modeled using the two-parameter Weibull density, the parameters of which vary with the surface being imaged. Techniques for detecting object boundaries in noisy radar images are proposed and compared. The images are assumed to be coarsely sampled, so that the (multiplicative) radar noise can be modeled as uncorrelated and identically distributed. Edge detection in multiplicative noise is effectively accomplished by thresholding ratios of locally adjacent image estimates. The efficacies of edge detectors defined as ratios of single order statistics, ratios of averages and ratios of best linear unbiased estimators (BLUEs) are compared. The comparisons are based on computed error probabilities as the Weibull parameters are varied. Several example images are provided for empirical comparison as well. >read more
Citations
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Journal ArticleDOI
Robust techniques for edge detection in multiplicative Weibull image noise
Robin A. Brooks,Alan C. Bovik +1 more
TL;DR: This paper defines and compares some novel techniques for the robust detection of sustained image irradiance changes, or edges, in images immersed in multiplicative Weibull noise, and suggests that edge detection using ratios of single order statistics (ROS detector) offers the best compromise among computational convenience, edge localization and robust performance.
References
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Journal ArticleDOI
Theory of Edge Detection
David Marr,Ellen C. Hildreth +1 more
TL;DR: The theory of edge detection explains several basic psychophysical findings, and the operation of forming oriented zero-crossing segments from the output of centre-surround ∇2G filters acting on the image forms the basis for a physiological model of simple cells.
Journal ArticleDOI
Some fundamental properties of speckle
TL;DR: In this paper, the distribution of scale sizes in a speckle pattern (i.e., the Wiener spectrum) is investigated from a physical point of view, and it is shown that adding M uncorrelated speckles on an intensity basis can reduce the contrast by 1/√M.
Journal ArticleDOI
Speckle analysis and smoothing of synthetic aperture radar images
TL;DR: This paper develops a statistical technique to define a noise model, and then successfully applies a local statistics noise filtering algorithm to a set of actual SEASAT SAR images, resulting in smoothed images that permit observers to resolve fine detail with an enhanced edge effect.
Journal ArticleDOI
A generalization of median filtering using linear combinations of order statistics
TL;DR: In this paper, the authors consider a class of nonlinear filters whose output is given by a linear combination of the order statistics of the input sequence, and choose the coefficients in the linear combination to minimize the output MSE for several noise distributions.