Analyzing the effect of incident angle on echo intensity acquired by hyperspectral lidar based on the Lambert-Beckman...

Hyperspectral light detection and ranging (HSL) can acquire the spatial and spectral information simultaneously, which can provide more information than hyperspectral imaging and single band lidar. However, the echo intensity from targets is influenced by incident angle, and relative studies were still limited which result in the effect of incident angle on HSL not being completely understood. In this study, the incident angle effect in the whole band of HSL was analyzed and corrected. Then, five types of vegetation sample with different spectral characteristics were collected at the leaf level. Spectral range changing from 550 to 830 nm with a 1 nm spectral resolution was obtained. Lambert-Beckman model was applied to analyze the effect of the incident angle on the echo intensity. The experimental results demonstrated that the Lambert-Beckman model can efficiently apply in fitting the changing of echo intensity with incidence angle and efficiently eliminate the specular effect of target. In addition, the coefficient of variation ratio is significantly improved compared to the reference target-based model. The results illustrated that, compared to reference target-based model, the Lambert-Beckman model can efficiently explain and correct the incident angle effect with specular reflection in HSL. In addition, it was found that the specular fraction Ks, which is reduced with the increasing of reflectance, is dominating the incident angle effect in the whole band, while roughness m keeps stable at different wavelengths. Thus, this research will provide notably advanced insight into correcting the echo intensity of HSL.