Analysis and Radiometric Calibration for Backscatter Intensity of Hyperspectral LiDAR Caused by Incident Angle
Wenxin Tian1,2, Lingli Tang1, Yuwei Chen1,3
1Key Laboratory of Quantitative Remote Sensing Information Technology, Aerospace Information Research Institute, Chinese Academy of Sciences (CAS), Beijing 100094, China.
Sensors (Basel, Switzerland)
|April 30, 2021
Summary
This study introduces an adaptive radiometric calibration method for Hyperspectral LiDAR (HSL) to correct incidence angle effects. The Lambertian-Beckmann model significantly improves HSL data accuracy, especially for natural surfaces.
Area of Science:
- Remote Sensing
- Optical Engineering
- Geophysics
Background:
- Hyperspectral LiDAR (HSL) offers advanced spatial and spectral detection capabilities.
- Laser echo intensity in HSL is influenced by various factors, necessitating calibration.
- Laser incidence angle significantly impacts target backscatter intensity.
Purpose of the Study:
- To develop and validate a radiometric calibration method for HSL addressing the incidence angle effect.
- To improve the accuracy of HSL backscatter intensity data.
- To provide a comprehensive model for diverse surface reflectance properties.
Main Methods:
- Proposed an adaptive threshold radiometric calibration method using a combination of the Lambertian and Beckmann models.
- Simulated natural surface reflectance as a mix of specular and diffuse reflection.
- Combined theoretical analysis with experimental validation to study HSL backscatter intensity and incidence angle relationships.
Main Results:
- The Lambertian-Beckmann model demonstrated higher calibration accuracy compared to the Lambertian model, with an average improvement of 22.67%.
- Calibration using the proposed model showed an average improvement rate of 62.26% for incidence angles below 70°.
- Identified significant specular reflection from green leaves in the 650-720 nm range, attributed to chlorophyll microstructure.
Conclusions:
- The Lambertian-Beckmann model offers a breakthrough for HSL radiometric calibration, particularly for surfaces with mixed reflection properties.
- The model effectively quantifies diffuse and specular reflectance coefficients, enhancing HSL data reliability.
- The findings provide valuable insights into the spectral characteristics of vegetation and improve HSL applications in the visible wavelength range.
