Laboratory Radiometric Calibration For Hyper-Spectrum Imager

Hyper-spectrum imager is an optical instrument that obtains images and spectral information at one time. This High Resolving capability Hyper- Spectrum Imager(HRHSI) obtains spectral image information with a high resolving power of ground. But practically, the information that imager obtained is not only related with the action spectrum and radiate luminance, but also influenced by atmospheric dispersion, permeate rate, attenuation and photoelectric transform rate of optic system and electric system. Due to these factors, the original digital image acquired by hyper-spectrum imager is different from radiance image of real target. So mature calibration is necessary, and the accurate calibrated results are foundation of processing and application of a variety of high quality quantitative analysis of remote sensor products. By laboratory radiometric calibration, we check the main performance indicators of remote sensors, obtain the basic parameters of radiometric calibration, and establish the image inversion formula.This thesis analyzed and summarized the significance and background to develop laboratory radiometric calibration, introduced the conception, sorts, contents and methods of radiometric calibration, summarized the calibration theory of HRHSI. To the question of the theory and characteristic of HRHSI, brought forward enforceable method and steps of calibration, accomplished laboratory radiometric calibration, described radiate characteristics of HRHSI. The integration sphere is used for simulating different radiance, which is decided by the different sun vertex angle and different reflectivity of the ground. The HRHSI is calibrated in lab, including absolute radiometric coefficient, dynamic range, photo response non-uniformity, Non-Linearity and Signal-to-Noise(SNR). Then absolute radiate response of each pixel, linear curve of photoelectric response and non-uniformity correction coefficients are obtained. At last uncertainty of calibration is discussed.The result shows that PAN of HRHSI is strictly linear within 960. After non-uniformity correction, non- uniformity will reduce from 10% to 0.3%. In the typical condition, SNR should be 380 at least, although integral time is 0.35ms.