1. Introduction
To maximise crop yield, blanket spraying of herbicides and insecticides is commonly used for weed and pest management. The application of such chemicals is often done terrestrially using an appropriately configured tractor or aerially, using a crop duster. A cost effective system for weed control, using spot-spraying of herbicides at appropriate periods during the cultivation cycle, is of interest to farmers due to the associated benefits of managed costs, reduced herbicide application and crop yield optimisation.
In recent years, the collective application of new technological advancements and improved management practices to farming has given rise to the field of Precision Agriculture (PA) (Zhang et al., 2002), of which a major aspect is Site-Specific Crop Management (SSCM) for optimised, efficient field-crop production. The management of weeds through an agricultural crop’s growth cycle, is one such area that has attracted considerable research interest. Reviews by Zwiggelaar (1998) and Noble et al. (2002) have concluded that weed/soil (green-from-brown) and crop/weed (green-from-green) discrimination, utilising spectral reflectance and hyperspectral/multispectral imaging techniques, has achieved