Commercial-off-the-shelf event-based cameras for space surveillance applications

Abstract

Event-based cameras (EBCs) are of interest for potential application to space domain awareness (SDA). EBC attributes, including asynchronous response and low latency provide data reduction, break the trade-off between latency and power, and enable consideration of additional algorithms and processing architectures due to individual timestamps for each event. Potential data reduction by a factor of 10 or greater is particularly attractive for SDA from satellite platforms with constraints on system power, processing, and communication bandwidth. Here we report our initial evaluation of Prophesee third-generation commercial-off-the-shelf (COTS) EBCs, including development of, and comparison with, a limiting magnitude model. The analytic model is a function of sky background radiance; EBC parameters including contrast threshold, dark current, pixel pitch, and spectral quantum efficiency; and the optic aperture diameter and focal length. Using an 85 mm f/1.4 lens, the measured detection limits for the half-size video graphics array (HVGA) and video graphics array (VGA)-format EBCs are 6.9 and 9.8 visual magnitudes ( m V ), respectively, at a sky background level of about 20.3 m V per square arcsecond. The empirical sensitivity limit for the VGA differs by 0.1 m V from our analytic prediction of 9.7 (less than 10% difference in flux). The limiting magnitude model assumes slow motion of point objects across the EBC focal plane array. Additional experiments exploring temporal behavior show that no stars are detected while scanning across the night sky faster than 0.5 deg per second using the VGA-EBC mounted to a 200 mm f/2.0 lens. The limited sensitivity of the evaluated COTS EBCs prevents their use as a replacement for typical CCD/CMOS framing sensors, but EBCs show clear promise for small-aperture, large-field persistent SDA in terms of their efficient capture of temporal information.

Research of event cameras in space object detection

“…For daytime observations, SDAVIS can detect Vega at a speed greater than 450pix/s at noon north latitude. The comparison of detection capabilities between traditional optical cameras and event cameras is shown in the table: Reference [27] quantitatively evaluated the spatial monitoring performance of Prophesee's third-generation commercial event camera, developed an extreme magnitude model, optimized the bias setting process for VGA event cameras, and added detection of dark stars. Compared to HVGA, VGA event cameras with high pixel resolution can detect darker stars.…”

Event-based camera refractory period characterization and initial clock drift evaluation

“…Public Affairs release approval # AFRL-2023-2933 and SDA/space traffic management. In terms of natural scene sparsity, event-based sensing is well-suited for application to a subset of SDA tasks where higher temporal resolution measurements (compared to what is currently provided by CMOS framing sensors) may provide additional information about the orbits and characteristics of manmade space objects [4][5]. However, key limitations of currently available COTS EBCs from the SDA perspective include high noise rates when viewing a dark scene, and challenges to measuring absolute time for each detected change event.…”

“…Commercial-off-the-shelf (COTS) event-based cameras (EBCs) are now available from multiple vendors [2], including iniVation (Switzerland) and Prophesee (France), to include the HD format (720x1280 pixels) 4 thgeneration model from Prophesee in collaboration with Sony [2][3]. Event-based sensing is of interest for low-SWaP machine vision and autonomous systems and is also being explored for long-standing remote sensing challenges such as space domain awareness (SDA) [2,[4][5]. Unlike well-developed and standardized methodologies to characterize CCD/CMOS framing cameras [6][7][8], complementary methodologies appropriate for EBCs are still in research and development [9][10][11].…”

A Neuromorphic Vision-Based Measurement for Robust Relative Localization in Future Space Exploration Missions

“…NVSs have a huge potential for future space missions given their unprecedented capabilities in harsh environmental conditions. Current space applications of the NVS are mainly limited to astronomical object tracking, such as stars and space debris [22], [36] and visual odometry for planetary robots [4]. In this work, we use NVS to enable relative localization under harsh space conditions.…”