Modulation transfer function of an imaging system with a hexagonal pixel array detector

Abstract The modulation transfer function (MTF) is the tool most commonly used for quantifying the performance of an electro-optical imaging system. Hexagonal sampling strategy for detector arrays can provide an improvement over rectangular sampling, thus the hexagonal pixel array detector is designed with hexagonal pixel and hexagonal sampling. In this paper, firstly, two dimensional MTF model of a hexagonal pixel array detector is deduced according to its definition. Then, the MTF of an imaging system with such a detector is established. Additionally, the MTFs of detectors with other shaped pixel geometry, but with the same photosensitive areas are compared. The results show that the values of hexagonal MTF are obviously larger than those of rectangular and triangular pixel array detectors at the same frequencies. In addition, with the increase of the atmospheric coherence length, the MTF values of the system become larger, and the system imaging capability will be improved.