Design and experiment for polarization imaging system of low-light-level image intensifier

In order to validate the feasibility that low-light-level(LLL) image intensifier achieves polarization imaging，according to polarization imaging theory, the LLL polarization imaging system was designed based on time-sharing polarization imaging technology. A 3rd generation image intensifier and a high dynamic range charge coupled device (CCD) were selected, a big dimension aperture objective lens and a relay lens were designed. The high transmissivity and high modulated transfer function (MTF) were achieved on image coupling. A digital CCD and a digital frame capture circuit with an embedded image process module were used. The correlative software about the image process was accomplished, so that the polarization imaging experiment was accomplished for the human target and the natural background in lab and field. The test results show that the contrast of the human target to natural background is 1.35 by the conventional imaging way, and is 2.35 by the polarization imaging system of LLL image intensifier, the contrast of the human target to the natural background is improved by LLL polarization imaging technology at night.