Gun muzzle flash detection using CMOS sensors

Abstract

This study focuses on the detection of muzzle flash detection of small arms using low cost silicon CMOS -based sensors and imagers. Two types of sensors are utilized: CMOS Image Sensors and CMOS-SPADs (Single Photon Avalanche Diodes). The detection approach is based on Near-Infrared (NIR) spectral features of muzzle flash originating from alkali metal flash suppressing additives in the gun powder. The spectral signature around wavelength of 760nm allows achieving adequate signal to noise ratio even in day light.

100 000 Frames/s 64 × 32 Single-Photon Detector Array for 2-D Imaging and 3-D Ranging

“…As the flash's capacitor discharges, the light intensity exponentially dims and fades out in about 2 ms. The acquired signal has a very similar shape (and bandwidth) compared to the muzzle response measured in [54], which exhibits a short 500 μs pulse followed by a longer 4 ms response.…”

“…For imaging applications, microlenses can get an expected 10x fill-factor improvement [53], even if this value greatly depends on the employed optical setup. Conversely, other applications exploiting each single pixel of the array as an independent single-photon counter (e. g. FCS) benefit from the low fill-factor [54].…”

“…Correspondingly, no limitation on minimum integration time, due to SNR degradation, is set (contrary to CCD and CMOS imagers) and sampling broadband signals becomes feasible. An example of high-speed imaging application is optical muzzle flash detection [59], which requires fast sensing of transient events with characteristic times between few microseconds up to some milliseconds, and where only recently, single-pixel SPADs have been tested [54].…”

Time-correlated single-photon counting range profiling and reflectance tomographic imaging

“…Examples of studied auxiliary applications using a TCSPC scheme include optical quantum key distribution [31], underwater optical communication [32], gun muzzle flash detection [33] and target discrimination in optical augmentation [34].…”