REMOTE FLUORESCENCE MEASUREMENTS OF VEGETATION SPECTRALLY RESOLVED AND BY MULTICOLOR FLUORESCENCE IMAGING

A remote sensing system for combined fluorescence spectral recordings and multi-colour fluorescence imaging of vegetation will be presented. The system configuration will be explained and data from several fiel d campaigns will be shown. The excitation light pulses for remote fluo rescence detection are produced by a frequency tripled Nd:YAG laser em itting at 355 nm and shifted to 397 nm in a deuterium containing Raman cell. The receiving optics includes a Newtonian telescope and is shar ed by an optical fibre bundle connected to an OMA system and by a seco ndary Cassegrainian split-mirror telescope for fluorescence imaging at four wavelength bands simultaneously. The multi colour fluorescence i mages are computer processed to form images of a ratio at two waveleng ths or if necessary a more complex mathematical function including the four wavelength bands is used. Examples of remote multi-colour imagin g of vegetation from the past field campaigns will be given. Remote fl uorescence spectra from several plant species were recorded at an exci tation wavelength of 397 nm. Furthermore, the system was found capable of producing high-quality single-shot spectra at a range of 125 m. La stly, a recently developed push-broom scanning technique for fluoresce nce imaging will be discussed and some preliminary data will be shown.