Analysis And Correction Of Stray Light For Mid-Wave Infrared Coded Aperture Spectral Imager

Spectral imaging technology combines spectral technology with imaging technology,which can simultaneously obtain two-dimensional spatial information of the target scene and one-dimensional spectral information of its identifiable units.The medium wave infrared aperture coding spectral imaging technology based on DMD devices has good application prospects in military reconnaissance,marine pollution monitoring,biomedicine,meteorological monitoring,and other fields due to its advantages of high light flux,high signal-to-noise ratio,and good real-time performance.However,there are serious stray radiation issues in the operation of the medium wave infrared aperture coding spectral imager.These stray radiation causes a decrease in the imaging quality and signal-to-noise ratio of the spectral imager,and also affects the accuracy of radiation calibration and the correctness of spectral restoration algorithms.This article focuses on the issue of stray radiation in existing medium wave infrared aperture coding spectral imagers.Firstly,based on the working principle of the system and the basic theory of stray radiation,the possible sources of stray radiation in the spectral imager were analyzed.Then,on the basis of constructing a simulation model of the spectral imager,stray light analysis was conducted on the spectral imager.Based on the numerical simulation results,the main sources and specific propagation paths of stray radiation within the system were determined,and the contribution values of each part of the imaging spectrometer to the overall stray radiation were calculated.It was determined that the main sources of stray radiation in the aperture coding spectral imager were the spontaneous emission of the DMD device frame inside the imager and the diffraction effect of the internal convex grating.Finally,for different sources of stray radiation,local temperature control and the establishment of Lyot apertures were proposed to suppress the stray light in the system.On this basis,a stray light suppression method based on differential encoding mask sequence is also proposed,which further corrects the stray radiation of the system from the perspectives of encoding and decoding.The effectiveness of the proposed stray light suppression method was verified through a combination of simulation and experimental verification.The research content of this article is of great significance for fully utilizing the design advantages of medium wave infrared aperture coding spectral imagers.