Name
Title | ||
|---|---|---|
Bias Correction and Modified Profile Likelihood Under the Wishart Complex Distribution |
Abstract | ||
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This paper proposes improved methods for the maximum likelihood (ML) estimation of the equivalent number of looks L. This parameter has a meaningful interpretation in the context of polarimetric synthetic aperture radar (PolSAR) images. Due to the presence of coherent illumination in their processing, PolSAR systems generate images which present a granular noise called speckle. As a potential solution for reducing such interference, the parameter L controls the signal-noise ratio. Thus, the proposal of efficient estimation methodologies for L has been sought. To that end, we consider first that a PolSAR image is well described by the scaled complex Wishart distribution. In recent years, Anfinsen have derived and analyzed estimation methods based on the ML and on trace statistical moments for obtaining the parameter L of the unscaled version of such probability law. This paper generalizes that approach. We present the second-order bias expression proposed by Cox and Snell for the ML estimator of this parameter. Moreover, the formula of the profile likelihood modified by Barndorff-Nielsen in terms of L is discussed. Such derivations yield two new ML estimators for the parameter L, which are compared to the estimators proposed by Anfinsen The performance of these estimators is assessed by means of Monte Carlo experiments, adopting three statistical measures as comparison criterion: the mean square error, the bias, and the coefficient of variation. Equivalently to the simulation study, an application to actual PolSAR data concludes that the proposed estimators outperform all the others in homogeneous scenarios. |
Year | DOI | Venue |
|---|---|---|
2014 | 10.1109/TGRS.2013.2285927 | Geoscience and Remote Sensing, IEEE Transactions |
Keywords | Field | DocType |
geophysical signal processing,maximum likelihood estimation,radar polarimetry,remote sensing by radar,speckle,synthetic aperture radar,Barndorff-Nielsen model,Monte Carlo experiments,PolSAR images,Wishart complex distribution,bias correction,granular noise,maximum likelihood estimation,modified profile likelihood,polarimetric synthetic aperture radar,second order bias expression,speckle,Image sensors,maximum likelihood estimation,multilook processing,parameter estimation,parametric modeling,radar data processing,radar polarimetry,radar signal processing | Monte Carlo method,Synthetic aperture radar,Remote sensing,Mean squared error,Estimation theory,Maximum likelihood sequence estimation,Wishart distribution,Mathematics,Method of moments (statistics),Estimator | Journal |
Volume | Issue | ISSN |
52 | 8 | 0196-2892 |
Citations | PageRank | References |
3 | 0.42 | 14 |
Authors | ||
3 | ||
Name | Order | Citations | PageRank |
|---|---|---|---|
| Abraao D. C. Nascimento | 1 | 97 | 7.11 |
| A.C. Frery | 2 | 132 | 8.86 |
| Renato J. Cintra | 3 | 218 | 26.82 |