Relative radiometric correction of DMD based coded aperture spectral imager in MWIR band

Abstract

The digital micromirror devices (DMD), as binary-coded masks, is an essential optical component in the coded aperture snapshot spectral imaging system (CASSI). However, DMD operating in MWIR or LWIR band usually introduces serious stray radiation by its diffraction effect, resulting in non-uniform images received by the CASSI. In this paper, we propose a new relative radiometric correction method for the DMD based CASSI in MWIR band. The method integrates a new coding method of CASSI and the traditional multipoint calibration method, and it can well suppress the nonuniformity noise of the infrared focal plane array. The working principle of the DMD based CASSI in MWIR band is introduced, then we design a new Hadamard coding mask, and investigate the corresponding decoding method. The mathematical mode of relative radiometric correction is established, and the relative radiometric calibration experiment is conducted to illustrate our method in detail. The experiment results indicate that the uniformity of the IR image at different temperatures corrected by the proposed algorithm is very good, and the temporal variation non-uniformity noise of the infrared focal plane array can be effectively suppressed.