Study On Imaging-spectrum Correction Methods Of Spatial Heterodyne Imaging Spectrometer

Spatial external aberration scanning imaging technology has the common characteristics of spatial external aberration spectroscopy and imaging technology,can obtain one-dimensional spectral and two-dimensional spatial information of an object in a single imaging session.,to achieve the spectral recovery of the target point in the detection area,with high luminous flux,ultra-high spectral resolution and other advantages,and simplifies the structure of the instrument,making the interferometric imaging spectrometer more practical and better imaging effect.It has significant scientific research significance and important applications in the fields of high spectral resolution atmospheric sounding,space sounding,earth observation,ocean remote sensing and national defence.The acquisition of interferometric image sequences to the accurate recovery of spectral information is the key to the application of spatial external aberration spectroscopy.This paper presents an in-depth study on the alignment correction of interferometric image sequences based on the principles of spatial external aberration spectroscopy and scanning imaging,and proposes an alignment processing algorithm for spatial external aberration scanning interferometric sequences,aiming to solve the error correction problem in the processing of image data.Firstly,the basic theory of spatial external aberration spectroscopy and the principle of scanning imaging are investigated to enable accurate processing to correct for image data errors,and the subsequent data processing of sequential images acquired by scanning imaging is discussed.By simulating the spatially epi-differential interferometric imaging system,the interferometric images obtained with a xenon atomic spectral light source as the incident light are recovered,and the spectra are recovered by Fourier transform of the interferometric images.The sources of error in the imaging and scanning system are then analysed and discussed qualitatively,including scanning platform displacement errors,detector non-uniformity errors,phase errors and errors during data processing.Through the analysis of the errors,an image correction scheme is proposed for the scanning platform displacement errors,including an interferometric image correction system flow,an algorithm for the elimination of spatially aberrant interference fringes,a phase-dependent image alignment,and a sub-pixel alignment of spatially aberrant interference images,to complete the error correction of spatially aberrant interference images.Finally,a high-precision scanning imaging experimental platform based on spatial external aberration spectroscopy is built to verify the reliability and effectiveness of the error correction algorithm for spatial external aberration scanning interferometric images.The image correction algorithm is applied to the acquired interferometric image sequences by first pre-processing the original interferometric images to eliminate interference fringes,then using the relevant correlation algorithm to complete the image sub-pixel alignment and error correction,and the feasibility of the image correction algorithm is verified by comparing and evaluating the alignment error and then reconstructing the mapping data cube.The experimental results show that by pre-processing and correcting the spatially out-of-difference scanned interferometric sequence images,i.e.using phase-dependent frequency-domain alignment while reducing the effect of interferometric modulation,the cumulative displacement during scanning imaging is greatly reduced,sub-pixel alignment is achieved,and the accuracy of spectral recovery is improved.