System Signal to Noise Ratio Measurement for Image Intensified Tubes

Image intensified systems are a compact, low power device that converts visible through near-infrared illumination to visible imagery. These devices provide usable imagery in a variety of ambient illuminations, and they are a preferred means for night imaging. Even though the device consists of objective or relay optics and an image intensified tube, to perform critical measurements on the device performance one needs to dis-assemble the device to perform testing on only the image intensified tube. This is a non-trivial process that requires the hardware to be re-aligned and re-purged during re-assembly. Using proper sources, reference cameras, and image processing techniques, it is possible to fully characterize an image intensified device for its relevant measurable parameters (signal to noise ratio, tube gain, and limiting resolution) without disassembly. This paper outlines the classic component image intensified measurement methodology, assumptions on performance that support those measurement techniques, and the new methodology procedure. A comparison of measurement results using both methods will demonstrate the validity of this new measurement approach.