Spectral radiance calibration method for spectroradiometers based on diffraction aberration factors correction.

Abstract

A spectroradiometer serves as a powerful instrument for measuring the spectral radiance of a target. The spectral radiance calibration function determines the measurement accuracy of the spectroradiometer. However, the general full-field calibration method results in higher spectral radiance values when dealing with targets that only partially fill the field of view (FOV). This error arises from the failure to account for the diffraction aberration factor, which represents the loss in response voltages on the spectroradiometer. To address this issue, we propose a spectral radiance calibration method based on diffraction aberration factors correction, which change with the FOV occupied by target. To obtain these factors, we have established a system where an infinite point source is conducted using a collimator and a blackbody incident on a pinhole. Different FOVs are achieved by adjusting the incident angle of the infinite point source. The experiment calibrated these diffraction aberration factors and demonstrates their spectral independence. Furthermore, the results highlight the effectiveness of the proposed method, even when the measured target is not circular and does not fully occupy the FOV.