Anomaly detection of hyperspectral image is active topic in the field of remote sensing image processing. Reed-X Detector (RXD) algorithm developed by Reed and Yu is a Constant False Alarm Rate (CFAR) anomaly detection method founded on multivariate statistical analysis theory, as the same form with Mahalanobis distance. RX detector could enable researchers to exploit targets that people particularly want from their surroundings according to the spectral distinct. So RXD is practicable in real scenes, and then becomes a focus in the field of target detection. RX detector has two common forms, Global-RX and Local-RX. They have different samples to estimate mean vector and covariance matrix. PCA is a common preprocessing step for dimension reduction. Interestingly, because it can also remove noises, performance could be improved by using principle components instead of all data. In addition, people often assume that RX result values submit the chi-square distribution, which often leads to an unacceptable high false alarm rate in setting χ²_α,p as threshold. So, how to get threshold value has been a difficult problem. This paper proposes a method based on multivariate statistical probability theory which can segment targets from image automatically. Instead of a constant threshold value, this segmentation target approach use an initial threshold calculated by RX result value histogram to separate backgrounds and targets samples, then calculate every pixel's posterior probabilities of background or target by assuming they all submit multi-dimensional normal distribution. Generally, the higher probability is considerable. The proposed method has been tested using AVIRIS data and the experimental results reveal that segmentation target approach has higher detection probability and lower false alarm rate compared with the traditional manual thresholding way.

Date Published: 24 May 2012
PDF: 7 pages
Proc. SPIE 8390, Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XVIII, 83902N (24 May 2012); doi: 10.1117/12.918399

Published in SPIE Proceedings Vol. 8390:
Algorithms and Technologies for Multispectral, Hyperspectral, and Ultraspectral Imagery XVIII
Sylvia S. Shen; Paul E. Lewis, Editor(s)