A fluorescence imaging endoscope system comprising a diode laser light source for producing excitation light having a wavelength in the range of 300 to 420 nm that induces visible fluorescence in tissue and a second light source for producing a reference light including red, green and blue wavelength bands, an optical combiner that optically couples said excitation light and said reference light onto a common optical path, said combined light being coupled into an optical guide that delivers the combined light to the tissue through an endoscope, a single image detector at a distal end of the endoscope that detects an autofluorescence image and a reference image of the tissue and a data processor that processes the autofluorescence image and said reference image to produce a processed output image of the tissue.
