Effects of the signal dependent noise on the CFARness of the RX algorithm in hyperspectral images

In this paper we investigate the effects of the signal dependent noise on the CFAR property of the RX anomaly detector. The CFAR behaviour of the algorithm was proved under the assumption of spatial stationarity of the random noise affecting the hyperspectral image. In data collected by new generation sensors such an assumption is not valid because photon noise contribution, which depends on the spatially varying signal levels, is not negligible. In this paper, experiments on real data collected by a new hyperspectral camera are discussed in order to show that the signal dependent noise is one of the causes of the non-CFAR behaviour of the RX detector we have experienced in many practical situations.