A Multi-Wavelength Canopy LiDAR for Vegetation Monitoring: System Implementation and Laboratory-Based Tests

Abstract

Abstract The instrumentation of a Multi-Wavelength Canopy LiDAR system (MWCL) for vegetation monitoring was tested by using low power, solid and semiconductor lasers. The proposed instrument takes measurements at four wavelengths which are highly interrelated to the chlorophyll concentration, Nitrogen content and other biochemical properties. The receiver consists of four channels, which would capture the LiDAR back-scatter signals of the four wavelengths separately at 556 nm, 670 nm, 700 nm and 780 nm. It is shown that the MWCL could not only provide structure information on vegetation canopy, but could also pick up the LiDAR intensity information. A 3-D reconstruction procedure based on the LiDAR back-scatter waveform has been done, and a supervised classification based on the intensity data is also accomplished. The results showed that the MWCL was able to significantly improve the retrieval accuracy of photosynthetically active biomass opposed to using a single-wavelength LiDAR alone.