Canopy architecture contributions to hot spot reflectance

The purpose of this study was to isolate factors contributing to the formation of the hot spot feature of vegetation canopy bidirectional reflectance. A model relating canopy architecture contributions to the formation of the hot spot was developed using a canopy divided into horizontal layers of equal leaf area index thicknesses. The basis for the model includes the use of gap, and foliage (or dark space) distributions. A dark space distribution function was developed as a part of this study. Directional reflectance data measured at the hot spot view angle were collected for alfalfa, coarse fescue turfgrass, and soybeans using a video recording system. The video data were digitized for the final analysis. A deconvolution procedure was used to remove penumbral shadow effects obscuring part of the hot spot intensity decrease away from the central peak value