Detection and performance analysis for a moving point source in speckle noise, application to exoplanet detection by direct imaging

Abstract

With the current development of astronomical instruments able to detect the direct light of exoplanets, such as the Very Large Telescope instrument SPHERE, statistical tools need to be developed in order to make precise detection and estimation assessments. We propose a detection algorithm that delivers an estimation of the position and the intensity of the potentially detected exoplanet. Because of the numerical constraints on the signal processing task, the detectorestimator is based on a simplified Gaussian model where we use a field-rotation effect as the main discriminating criterium between the planet and the speckles. However, for a given threshold on the statistics test, the Probability of False Alarm (PFA) and the Probability of Detection (PD) need to be accurate. For that purpose we use a more realistic model and the saddlepoint approximation to compute the PFA and PD. The performance of the approximation is evaluated on a 1D data model.