Observational Evaluation of Event Cameras Performance in Optical Space Surveillance

Abstract

Dynamic vision sensor (DVS) event cameras possess a unique feature of outputting only sparse and asynchronous brightness changes rather than the conventional image sensor measurement of average intensity level during a fixed exposure time. This new technology opens a window of opportunity for SST, especially for survey observations, where users are mostly interested in detecting objects moving within the telescope's field of view. In this work we present a comparison between a regular global-shutter CMOS camera (QHY174-GPS) and several DVS-based DAVIS cameras, which can concurrently output standard frames and DVS events. The measurements include new sensors, so far uncharacterized for space surveillance, specifically the first back illuminated DAVIS (BSIDAVIS) and a DAVIS with more sensitive temporal contrast threshold (SDAVIS). The sensors were observationally tested during stellar observing runs with varying telescope tracking speed to simulate SST targets on different orbits, using identical optics and under the same weather conditions. Observations included daytime sky targets with high sky brightness. The minimum detectable object magnitudes and maximum object speeds were quantitatively assessed. The potential of existing event-based sensors is evaluated and future upgrades to DVS designs to fully utilize this technology in SST are discussed.