Infrared Camera Simulation for Estimating Spatial Temperature Profiles and Signal-to-Noise Ratios of an Airborne Laser-Illuminated Target

摘要

Airborne Laser testing and evaluation can be aided by developing a spectrally-based infrared camera simulation to explore how the target surface's specular and diffuse reflectivities affect the observed signal-to-noise ratio (SNR) and how the target's temperature in the laser spot can estimated. This simulation provides for the observed irradiance, scaled by atmospheric absorption, to consist of the target's self-emission, reflected background emission, and the path emission from the observer to the target. The observed irradiance is scaled and distributed onto a focal plane array by way of a simulated optical system, whose effects are described by modulation transfer functions. The modeled detector response converts the observed irradiance to a current signal from which detector noise quantities are computed. Analyzing the simulated data shows that the observed SNR is dependent upon the target's reflectivity, and leads to a conclusion that the mid-wave infrared band is best choice for observing the thermal emission. For estimating temperature, a least- squares optimization will not work because of the effects of the point spread function.