Zhuoyue Hu
ShangHai Institute of Technical Physics of CAS, China
Title: A Study of camera on orbit radial calibration based on blackbody and infrared calibration stars
Biography
Biography: Zhuoyue Hu
Abstract
In view of the radiometric calibration of large aperture optical systems, a parallel light coupling method is proposed to achieve non-uniformity correction and radiometric calibration through the internal blackbody into the optical path. The sensor consists of two parts, the front optical system and the rear optical system. Between the front optical system and the rear optical system is connected by parallel light, which is the characteristic of this calibration system. Its calibration system includes image space blackbody and calibration mirror. In this paper, the relative radiation calibration is realized by an internal blackbody. We establish a response database with integral time and blackbody energy as a variable and a nonlinear nonuniformity correction algorithm based on variable integration time and variable energy are adopted to achieve the relative radiometric calibration of the image. Th rough the non-uniformity correction algorithm, we get the result which is better than 0.2%. It shows a better result than the two-point correction and multi-point correction. We also use the star and internal blackbody to monitor the stability of the camera, we chose the star which satisfi es the Radiation theory, it is easy to find the star and simplify the process. By comparing with the internal blackbody calibration, the calibration method based on the WISE star table can achieve the calibration accuracy better than 10%. We found that the system stability result of the back optical is within 3% and the front optical is within 5% for 8 months. According to the requirement of calibration precision, the frequency
of calibration is designed.