| With the development of infrared remote sensing detection technology,the camera’s caliber is growing,the traditional on-orbit calibration sources are no longer applicable to the large remote sensor.Currently,the on-orbit calibration methods of large-aperture space optical remote sensor include: multi-sensor cross-calibration,feature calibration,internal black body calibration and celestial body calibration.The method of calibration based on celestial bodies is a kind of high precision calibration method because of its all-optical path and no interference from the atmosphere,including lunar calibration and stellar calibration.The calibration method of stellar based on infrared catalog has become a main on-orbit calibration method because of its advantages,such as stable radiation characteristics,simple calibration link and large dynamic range.We first establish the energy extrapolation model based on WISE catalog,and use the optimized traditional genetic algorithm and Taylor expansion method to study the irradiance of 1000 stars of WISE catalog in different bands,as a result the proportion of the stellar that extrapolation accuracy <3% is 68.34% which satisfies the project’s requirements.Based on the extrapolation model,the star irradiance is extrapolated to the camera’s detection band to form a dedicated calibration star library.Star recognition is the premise of radiation calibration,we focus on star map preprocessing methods and triangle recognition algorithm.For the single frame image,we use the method which is based on weighted local difference entropy to extract stellar.To confirm the single detection result,multi-frame image relevance is needed.Then we use the traditional centroid extraction algorithm to extract stellar centroid and get accuracy as sub pixel.As for star recognition,The WISE catalog is the original guide star database,we realize the triangle algorithm and verify the recognition result with verified stellar.In this paper,we study the on-orbit calibration method based on WISE catalog extrapolation,and use camera to verify the calibration methods by stellar experiment on ground.According to the star map recognition result and the extrapolation model,we calculate the star energy in the camera band,at the same time we extract stellar measured DN based on Gaussian point spread function(PSF)model and calculate the measured error.The experimental calibration result shows: when the WISE catalog system error is about 5%,the irradiance extrapolation error is about 3%,the atmospheric transmittance error is about 15%,measured DN error is about 5%,the on-ground accuracy of calibration methods based on WISE catalog extrapolation is about 21%;When this calibration method applies to on-orbit calibration,the atmospheric transmittance error does not existed,the on-orbit accuracy of calibration methods based on WISE catalog extrapolation is about 10%... |
