Anhui Institute of Optics and Fine Mechanics (AIOFM), Hefei Institute of Physical Science completes the detailed design of "Visible light-shortwave infrared spectrum radiation colorimetric calibration system", which is China's first set of commercial laboratory spectral radiation colorimetric calibration system and is designed by CHEN Hongyao's team. By now, the detailed design of the calibration system has been approved.

The calibration system consists of three subsystems: the spectral calibration system, the radiation calibration system and the colorimetric calibration.

The spectral calibration system is used to determine the spectral response function of the entire camera system, and then determine the spectral characteristics of the spectral channel parameters (such as: work spectrum, peak wavelength, spectral bandwidth, out of band response, etc.), it can also complete the absolute spectral calibration results calculated combined with radiation calibration data.

The radiation calibration system mainly includes relative radiation calibration and absolute radiation calibration. The former one is aimed to correct the difference in response among different camera components. The latter one is targeted to establish the quantitative relationship between the spectral radiance value at the entrance pupil of the different camera segments and the digital quantization value (image gray value) of the output.

The colorimetric calibration system mainly consists of standard light room, color targets, spectrum radiometer and data processing software. On the calibration time, imaging the color targets with the camera under the condition of standard light source illumination combine with the targets reflector radiance measured by the spectral radiometer, through the analysis of data processing, the system can complete the colorimetric calibration and correction of the camera.

The entire calibration system is designed to meet the laboratory spectrum/radiation/colorimetric calibration requirements of visible-shortwave infrared band aviation/aerospace and terrestrial photoelectric imaging /detection equipment.

CGST Co.,Ltd is China's first commercial remote sensing satellite company founded on Dec 1st, 2014 in Changchun. And AIOFM’s "Visible light-shortwave infrared spectrum radiation colorimetric calibration system" project will lay the foundation for establishing a complete physical imaging model for optical remote sensors as well as provide technical support for optical remote sensor life cycle calibration and improving the quantitative level of remote sensing data products. In the near future the two sides will also join hands in other fields to promote the industrialization of quantitative remote sensing in China.

The Calibration System schematic diagram (Image by LI Jiawei)