Detecting a pneomothorax in neonates. Detecting atheromatous plaque in blood vessels using fluorescence or IR Raman. The spatial distribution of a measured parameter must be mapped. The mode of contrast can be based either absorption, scattering, fluorescence, or IR Raman scattering. Combining spectroscopy with imaging yields a spectrally weighted image.
Optical images are usually fuzzy, but they have spectral content and can yield functional mappings.