**4. Proxy-detection image processing for weed-wheat crop discrimination by hyperspectral imagery**

In the domain of weed control, since the environmental and economical stakes are particularly great, the herbicides are largely spread in order to assure sufficient yields for the whole field whatever the infestation rate.

The reason is essentially a technological one. Even if some low-cost devices are currently available to assure a localised spraying of herbicides on bare soil (vegetation detection by photoelectric cells), no commercial product allows a reliable and localised post-emergence treatment. Indeed, a such apparatus needs a sophisticated perception system, based on digital vision and allowing to distinguish between weeds and crops. The identification of varieties inside the vegetation is nowadays the principal lock to the development of localized weed control.

The corresponding research are numerous and can be divided into two main approaches (Slaughter et al., 2008):


The study proposed in this chapter is tied to the previous approach: hyperspectral images of the wheat crop are acquired during the weed control period, and associated to specific preprocessing to avoid illumination conditions. After, the possible spectral discrimination between wheat and dicotyledonous weeds by means of chimiometric tools has been evaluated.
