Chinese Space Science and Technology ›› 2025, Vol. 45 ›› Issue (4): 37-47.doi: 10.16708/j.cnki.1000-758X.2025.0056

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A multi-angle spectral curve inversion model based on BRDF

LIU Zhen1,2, SUN Xu2,*, SHA Jianjun1, SUN He2, WANG Degang2,3, GAO Lianru2   

  1. 1.Qingdao Innovation and Development Center of Harbin Engineering University, Qingdao 266000, China
    2.Aerospace Information Research Institute, Chinese Academy of Sciences,Beijing 100094, China
    3.University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2024-09-30 Revision received:2025-01-13 Accepted:2025-01-22 Online:2025-07-22 Published:2025-08-01

Abstract: To address the issue of low matching detection accuracy caused by differing inclination angles between the a priori spectral library and the measured hyperspectral image acquisition, a tilted spectral curve inversion model is proposed based on a kernel-driven bidirectional reflectance distribution function (BRDF). The spectral curves are firstly split according to the wavebands, and then the relationship between the reflectance of each waveband and the detection inclination is fitted according to the BRDF equation, to establish the reflectance inversion model. For the hyperspectral images collected at a specific inclination angle, the inversion algorithm is used to perform the a priori spectra at the corresponding inclination angle and match the detection. In the experiment, the multi-angle spectral data of the desert camouflage net and its background dry grassland are collected using the independently designed and assembled field multi-angle spectral measurement system, their spectral characteristics are analyzed, and the performance of various inversion algorithms is compared. The experimental results show that the reflectance of different features varies with the detection inclination in a similar trend, respectively, and the differences between the fitted and measured spectral curves are small, with the coefficients of determination of the two exceeding 0.83, and the spectral pinch angles of the spectra are all less than 1°. Compared with the a priori spectra acquired at different inclination angles, the a priori spectra generated by the inversion model with the same angle as the image acquisition have improved AUC values in the matched detection. The research enriches the related studies of multi-angle remote sensing and effectively applies multi-angle remote sensing to the field of hyperspectral target detection. Through the established inversion model, the accuracy of hyperspectral image matching detection is improved, which is of theoretical and practical significance. 

Key words: multi-angle remote sensing, BRDF, spectral curve inversion, inclined measurement, hyperspectral target detection