Analysis and Radiometric Calibration for Backscatter Intensity of Hyperspectral LiDAR Caused by Incident Angle Effect
Wenxin Tian,
Lingli Tang,
Yuwei Chen,
Ziyang Li,
Jiajia Zhu,
Changhui Jiang,
Peilun Hu,
Wenjing He,
Haohao Wu,
Miaomiao Pan,
Jing Lu,
Juha Hyyppä
Affiliations
Wenxin Tian
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Lingli Tang
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Yuwei Chen
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Ziyang Li
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Jiajia Zhu
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Changhui Jiang
Department of Photogrammetry and Remote Sensing, Finnish Geospatial Research Institute (FGI), FI-02430 Masala, Finland
Peilun Hu
Department of Photogrammetry and Remote Sensing, Finnish Geospatial Research Institute (FGI), FI-02430 Masala, Finland
Wenjing He
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Haohao Wu
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Miaomiao Pan
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Jing Lu
Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China
Juha Hyyppä
Department of Photogrammetry and Remote Sensing, Finnish Geospatial Research Institute (FGI), FI-02430 Masala, Finland
Hyperspectral LiDAR (HSL) is a new remote sensing detection method with high spatial and spectral information detection ability. In the process of laser scanning, the laser echo intensity is affected by many factors. Therefore, it is necessary to calibrate the backscatter intensity data of HSL. Laser incidence angle is one of the important factors that affect the backscatter intensity of the target. This paper studied the radiometric calibration method of incidence angle effect for HSL. The reflectance of natural surfaces can be simulated as a combination of specular reflection and diffuse reflection. The linear combination of the Lambertian model and Beckmann model provides a comprehensive theory that can be applied to various surface conditions, from glossy to rough surfaces. Therefore, an adaptive threshold radiometric calibration method (Lambertian–Beckmann model) is proposed to solve the problem caused by the incident angle effect. The relationship between backscatter intensity and incident angle of HSL is studied by combining theory with experiments, and the model successfully quantifies the difference between diffuse and specular reflectance coefficients. Compared with the Lambertian model, the proposed model has higher calibration accuracy, and the average improvement rate to the samples in this study was 22.67%. Compared with the results before calibration with the incidence angle of less than 70°, the average improvement rate of the Lambertian–Beckmann model was 62.26%. Moreover, we also found that the green leaves have an obvious specular reflection effect near 650–720 nm, which might be related to the inner microstructure of chlorophyll. The Lambertian–Beckmann model was more helpful to the calibration of leaves in the visible wavelength range. This is a meaningful and a breakthrough exploration for HSL.
