Comparison of spectral and spatial windows for local anomaly detection in hyperspectral imagery |
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Authors: | Zhiyong Li Jonathan Li Shilin Zhou Saied Pirasteh |
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Affiliation: | 1. School of Electronic Science and Engineering, National University of Defence Technology, Changsha, Hunan 410073, China;2. Department of Geography &3. Environmental Management, Faculty of Environment, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1lzylmz75@gmail.com;5. Department of Geography &6. Environmental Management, Faculty of Environment, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1;7. School of Information Science and Engineering, Xiamen University, Xiamen, Fujian 361005, China |
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Abstract: | A new way of implementing two local anomaly detectors in a hyperspectral image is presented in this study. Generally, most local anomaly detector implementations are carried out on the spatial windows of images, because the local area of the image scene is more suitable for a single statistical model than for global data. These detectors are applied by using linear projections. However, these detectors are quite improper if the hyperspectral dataset is adopted as the nonlinear manifolds in spectral space. As multivariate data, the hyperspectral image datasets can be considered to be low-dimensional manifolds embedded in the high-dimensional spectral space. In real environments, the nonlinear spectral mixture occurs more frequently, and these manifolds could be nonlinear. In this case, traditional local anomaly detectors are based on linear projections and cannot distinguish weak anomalies from background data. In this article, local linear manifold learning concepts have been adopted, and anomaly detection algorithms have used spectral space windows with respect to the linear projection. Output performance is determined by comparison between the proposed detectors and the classic spatial local detectors accompanied by the hyperspectral remote-sensing images. The result demonstrates that the effectiveness of the proposed algorithms is promising to improve detection of weak anomalies and to decrease false alarms. |
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