I. Introduction and Background
Fluorescence microscopy is a powerful discriminative tool for the rapid identification of target organisms. With appropriate filters and excitation conditions, the signal to noise ratio provided by conventional fluorescence microscopy is excellent and greatly reduces the tedium of locating and identifying organisms of interest to the microscopist. Frequently however, natural autofluorescence (non-specific intrinsic fluorescence) can intrude to such an extent as to render conventional techniques useless [1]–[3] and a further selection parameter is required to regain discriminative ability.