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Experimental research for relative radiometric calibration of imaging spectrometer based on Savart plates

The basic principle of tempo-spatially mixed modulated Fourier transform imaging spectrometer (FTIS) based on savart plates is outlined. A calibration method of pixel response non-uniformity of charge-coupled device (CCD) camera in such type of instrument is presented. The method which uses column-flat-fields can avoid the influence of interference fringes. The use of polychromatic calibration source can solve the problem of the slant of the fringes in large optical path difference areas. The procedure of calibration experiment and the algorithm of data processing are detailed described. Two groups of relative radiometric calibration coefficient are obtained through the method of least-square. The original images are corrected by using the coefficients to validate its calibration effect. The results indicated that the method can obviously improve the uniformity of pixels and the vignetting artifacts and defect of the instrument can be well corrected. This study provides a theoretical guidance for study, design, modulation, experiment and engineering of FTIS.