Maximized subspace model for hyperspectral anomaly detection

An important application in remote sensing using hyperspectral imaging system is the detection of anomalies in a large background in real-time. A basic anomaly detector for hyperspectral imagery that performs reasonaly well is the RX detector. In practice, the subspace RX (SSRX) detector which deletes the clutter subspace has been known to perform better than the RX detector. In this paper an anomaly detector that can do better than the SSRX detector without having to delete the clutter subspace is developed. The anomaly detector partials out the effect of the clutter subspace by predicting the background using a linear combination of the clutter subspace. The Mahalanobis distance of the resulting residual is defined as the anomaly detector. The coefficients of the linear combination are chosen to maximize a criterion based on squared correlation. The experimental results are obtained by implementing the anomaly detector as a global anomaly detector in unsupervised mode with background statistics computed from hyperspectral data cubes with wavelengths in the visible and near-infrared range. The results show that the anomaly detector has a better performance than the SSRX detector. In conclusion, the anomaly detector that is based on partialling out can achieve better performance than the conventional anomaly detectors.