Spectral matching factors between Super S25 and New S25 photo cathodes and reflective radiation of objects

According to the response of photoelectric device to a light source, the formula of spectral matching factor of photo cathode-object combination is deduced. The spectral matching factors of Super S25 and New S25 photo cathodes for green vegetation and rough concrete are calculated and compared. For Super S251, the spectral-matching factors for green vegetation and rough concrete are 0.707 and 0.743, respectively, under the full-moon radiation and are 0.504 and 0.577, respectively, under the clear-star radiation. For Super S252, the full-moon factors are 0.561 (green vegetation) and 0.732 (rough concrete), and those for clear-star radiation are 0.338 (green vegetation) and 0.471 (rough concrete). For New S25, the full-moon factors are 0.741 (green vegetation) and 0.762 (rough concrete), and those for clear-star radiation are 0.603 (green vegetation) and 0.657 (rough concrete). An analysis of results shows that the spectral-matching factor has influence on the performance of a low-light level night vision system and is essential for evaluating the visual range of a night-vision system.