Abstract: An apparatus for emulating various known night sky illumination conditions. The apparatus comprises a plurality of electrically-powerable LEDs which are disposed in an array and have respective spectral curves centered at different wavelengths in the visible to the short wave infrared wavebands, and means for fixing the temperatures of the LEDs to avoid temperature-induced changes in their spectral curves. Additionally, the apparatus includes means for varying the light intensities of the individual LEDs so that the combination of their spectral curves matches the spectrum of the known night sky illumination condition to be emulated, and means for regulating the total amount of light collected from the array so that the cumulative spectrum has the same intensity as the known night sky illumination condition to be emulated.

Abstract: A three dimensional true color holographic imaging system using three primary color Fresnel-Zone-Pattern laser generators combined as a single beam that scans the target and the reflections of which are sensed simultaneously by a single electronic detector. The detector signals corresponding to each generator are then separated electronically and independently recorded.