Range-resolved Image Detection of Laser-induced Fluorescence of Natural Trees for Vegetation Distribution Monitoring

Abstract

Fluorescence images of in vivo and natural tree leaves induced by the second harmonic of a Q-switched YAG laser have been remotely and directly detected by a lidar with a gated image-intensified charge-coupled-device (II CCD) camera. Simple spectroscopic measurements using a colored glass filter showed that the fluorescence was caused by the chlorophyll in the leaves. The chlorophyll fluorescence was useful to distinguish trees and other objects. Tree locations up to a distance of around 150 m from the system were also determined with a range resolution of 15 m from the range-resolved fluorescence images. The results showed that this technique has a great potential use as a monitor of vegetation distribution.