Topic
K-distribution
About: K-distribution is a research topic. Over the lifetime, 1281 publications have been published within this topic receiving 51774 citations.
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01 Sep 2006
TL;DR: This paper addresses the problem of estimating the parameters of these bivariate gamma distributions by using the maximum likelihood method and the method of moments, and compares the performances of both estimators.
Abstract: Determining similarity measures between two images is a interesting problem for image registration or change detection. Bivariate gamma distributions are good candidates for radar images since their marginals are known to be univariate gamma distributions. This paper addresses the problem of estimating the parameters of these bivariate gamma distributions by using the maximum likelihood method and the method of moments. The performances of both estimators are compared. Asymptotic expressions for the estimation variances are also derived.
7 citations
TL;DR: In this paper, the spatial statistics of a C-band airborne polarimetric SAR system operated by the Defence Research Agency (DRA) of the U.K. were investigated using Gaussian and K distribution models.
Abstract: A prerequisite for the design of any target detection scheme is an understanding of the surrounding clutter environment. This paper aims firstly to investigate the extent to which Gaussian and K distribution models can be used to represent genuine polarimetric SAR clutter and secondly to investigate the spatial statistics of such clutter. To this end data analysis has been performed on imagery obtained using a C -band airborne polarimetric SAR system operated by the Defence Research Agency (DRA) of the U.K. In particular, the behaviour of the single point and spatial statistics between polarimetric channels has been investigated. Both an uncorrelated Gaussian model and a correlated K distribution model have been found to be required to fit the different clutter types encountered. However no inter-channel variation in single point or spatial statistics has been detected.
7 citations
TL;DR: In this paper, the distributions of Hadamard coefficient for blocks of size 8 × 1 picture elements in six 625-line television pictures were obtained, and the data were well approximated by gamma distributions.
Abstract: The distributions of Hadamard coefficient for blocks of size 8 × 1 picture elements in six 625-line television pictures were obtained. The data were well approximated by gamma distributions. Low-sequency components were best fitted by choosing ?(n) with n in the range 1/2?2/3, and high-sequency components by n = 1 (equivalent to the negative exponential distribution).
7 citations
Patent•
05 Feb 2015
TL;DR: In this article, a radio-frequency interferometry method for determining parameters of motion of a moving object from phase difference information from an antenna baseline formed of two antennas is proposed, where a posterior probability density function from the phase differences from the baseline, separate the modes with a threshold value of probability density, and compute a probability of each mode.
Abstract: A radio-frequency interferometry method for determining parameters of motion of a moving object from phase difference information from an antenna baseline formed of two antennas. At each of a plurality of observation events, compute a posterior probability density function from the phase differences from the baseline, separate the modes with a threshold value of probability density, and compute a probability of each mode. For each possible sequence of modes, determine a mode sequence probability as the product of the probabilities of each mode in that sequence, estimate a χ 2 goodness of fit function based on an assumed type of motion. Determine the net probability of each possible sequence of modes as the product of a relative probability derived from the χ 2 and the mode sequence probability. Alternately, two or more parallel or colinear baselines are used, and the posterior PDF is a combined PDF over each of the baselines.
7 citations
TL;DR: This work has defined a new bivariate pseudo-Weibull distribution that can be thought of as suitable alternatives to the standard probability distributions of multicomponent systems.
7 citations