A comparison of different techniques for passive measurement of vegetation photosynthetic activity: solar-induced fluorescence, red-edge reflectance structure and photochemical reflectance indices

Measurement of vegetation photosynthetic activity from space has been an objective for the development of new techniques. Among the different existing techniques, passive fluorescence measurements, specific reflectance indices such as the PRI (Photochemical Reflectance Index), and the derivative of high spectral resolution reflectance in the red-edge (680 - 750 nm) are the three methods that can be used as remote sensing techniques from airborne and space sensors and that have proven to give consistent and reliable information about the canopy photosynthetic activity.