Performance characterization of low light level color imaging sensors

Abstract

Low light level (LLL) color vision is becoming more obtainable with improvements in Complementary Metal Oxide Semiconductor Sensor (CMOS) imagers. It is drawing interest in the commercial, military, and first responder communities. Since human perception under LLL conditions is mainly monochrome, what level of color determination is sufficient? For example, is a simple red, yellow, and green street light determination good enough, or is additional color rendering required? Does a speeding car need to be identified as red, or as cherry red? Does a Soldier need to determine if the liquid on a uniform is blood, oil, or water? Additionally, the operator needs to understand that adding specific color capabilities may come at the expense of system performance under LLL conditions. This project seeks to obtain user input, discuss the operating conditions during which personnel would want to have color information, and discuss measurement techniques and methodology standards for color LLL cameras (such as color fidelity, L*a*b* color space, signal-to-noise measurements, luminance uniformity, and color accuracy) that can be utilized by interested stakeholders. We will also discuss the filtering of an incandescent source to create moon-like spectral emission in our laboratory. Preliminary results from color low light camera evaluations at the C5ISR – Night Vision and Electronic Sensors Directorate (NVESD) will be presented.