• Spectroscopy and Spectral Analysis
  • Vol. 40, Issue 3, 837 (2020)
LI Ling, WU Zhi-feng, WANG Yan-fei, and DAI Cai-hong
Author Affiliations
  • [in Chinese]
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    DOI: 10.3964/j.issn.1000-0593(2020)03-0837-05 Cite this Article
    LI Ling, WU Zhi-feng, WANG Yan-fei, DAI Cai-hong. The Effects of Light Source Differences on Array Spectroradiometer Measurements and the Research of Ultraviolet Stray Light Correction[J]. Spectroscopy and Spectral Analysis, 2020, 40(3): 837 Copy Citation Text show less

    Abstract

    With the goal of climate change prediction and disaster weather prevention, high accurate spectral radiance calibration is required in earth observation. Array spectroradiometers have problems such as internal structural defects and unsatisfactory optical components, resulting in stray lights, which seriously affect the spectral radiance measurements. In this paper, the stray lights of various typical array spectroradiometers were measured. The different spectrums of solar radiance and the laboratory calibration lamp were analyzed. Ultraviolet stray light correction methods were studies by using bandpass filters and tunable lasers, respectively. First, bandpass filters with specific transmittances were used to measure ultraviolet stray light signals. The mathematical correction model was established to realize the efficient evaluation and simple correction. The ultraviolet stray light of the solar radiance in ground-based verification site was obviously reduced by using this method. For the continuously distributed wide-spectrum light sources, the correction method with bandpass filter is of simple experimental conditions and efficient work process. However, it is difficult to complete the high accurate stray light correction for the discontinuous distribution or narrow-band light source. Therefore, the stray light measurement system based on tunable laser was established, which can measure the stray light line-spread function of each pixel by changing the output wavelength of the tunable laser, and then the stray light correction results of each pixel are calculated by MATLAB matrix operations. The correction method was verified by different types of array spectroradiometers. For measuring the non-continuously distributed narrow-band source, the stray light signal was reduced by an order of magnitude, and the inter-reflection peaks beside the light source were significantly eliminated. Here, two stray light correction methods with complementary advantages were established for different spectral distribution light sources, which effectively decreased the deviation of the UV measurement results of array spectroradiometers, further ensuring the accuracy of Chinese earth observation data.
    LI Ling, WU Zhi-feng, WANG Yan-fei, DAI Cai-hong. The Effects of Light Source Differences on Array Spectroradiometer Measurements and the Research of Ultraviolet Stray Light Correction[J]. Spectroscopy and Spectral Analysis, 2020, 40(3): 837
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