Red Edge mapping - Terrascan Labs LTD
Red edge refers to the region of rapid change in reflectance of vegetation in the near infrared range of electromagnetic spectrum. Chlorophyll contained in vegetation absorbs most of the light in the visible part of the spectrum but becomes almost transparent at wavelengths greater than 700 nm. This way, vegetation cellular structure takes its major part in the reflectance because each cell acts like an elementary corner reflector. This effects in that rapid change that can be from 5% to 50% reflectance between 680 nm to 730 nm. For a more detailed explanation and a graph of the photosynthetically active radiation (PAR) spectral region, see the NDVI rationale.