Blurred spectral images restoration technology for AOTF imaging spectrometer based on dual-path architecture

Abstract

The acousto-optic tunable filter (AOTF) imaging spectrometer is a staring-type instrument that acquires spectral images of different bands asynchronously and sequentially, and is susceptible to platform jitter and target motion. When the integration time of the detector increases, serious spectral images degradation occurs along with a large band-to-band misregistration. The dual-path optical configuration, capable of simultaneously acquiring diffracted and undiffracted beams of AOTF, has been shown to be effective in solving the problem of band-to band misregistration. Hence by solving the remaining spectral image degradation problems, the application range of AOTF will transcend the previous limitation. Therefore, this paper presents a new, to the best of our knowledge, method of capturing a series of short-exposure undiffracted beam images to calculate the blur kernel of the diffracted spectral images, since the high-intensity characteristics of the undiffracted beam can also be exploited in the dual-path system. The paper starts with analyzing the impact of the platform on spectral images, and then demonstrates the development and calibration of a dual-path based spectral image deblurring method. Finally, laboratory experiment verifies that the resulting blur kernel can be effectively used for spectral image restoration, thus demonstrating the robustness of this technique.