Résumé
In the study presented here, we used a pushbroom CCD camera fitted on a motorised rail fixed on a tractor to take wheat plot images. The camera has a spectral range from 0.4 μm to 1 μm, a spectral resolution of 3.7 nm and 160 wavebands. The spatial resolution across track, which is fixed by the lens and the camera view angle, is 0.2 mm at 1 m above the canopy. The spatial resolution along track, depending on the motion speed, can be adjusted between 0.2 and 5 mm. Images have been radiometrically corrected with data given by the camera constructor to obtain signal in radiance. A ceramic plate was calibrated in laboratory and used as a reference to obtain solar lighting and correct the images in reflectance. Once the images have been corrected with respect to illumination conditions, they provide us with reflectance spectra. The corrected spectra have been compared to spectrometer measurements. Though the results show the pertinence of our correction process, additional phenomena must still be taken into account (e.g. leaf orientation and canopy architecture). They will be investigated in further studies.