Block diagram of the reflectance recovery process. The sequence start with the scanning of the target scene. Data are then post-processed, here the calibration model compensates for the system spectral response which gives the spatio-spectral data cube. Then, the spatio-spectral reading identifies the specific wavelength of maximum absorbance that allows to characterize the pigment intensity change. Finally, the pigment signal is plotted as a function of time. Here, each point is a scanning sequence at that time. The scanning frequency is of the order of hours for the lag and stationary phase and half an hour for the exponential phase.