Multispectral imaging system and method

In a method of multispectral imaging comprising the steps of producing spatial pictures of an image scene in a plurality of different spectral wavelength bands and utilizing differences in the observed spatial image at different wavelengths for detecting a feature of the scene, the improvement comprising simultaneously comparing a wavelength spectrum observed for a spatial pixel of a spatial picture of an image scene with a plurality of template wavelength spectra to find a correlation, wherein said simultaneously comparing includes:

• modulating the light of respective ones of a plurality of spectral bands of said wavelength spectrum to independently alter at least one property of the light by a representative value corresponding to the observed intensity of the wavelength spectrum in the respective spectral band,
• expanding a beam of the modulated light in a spatial dimension perpendicular to a direction of wavelength ordering of said wavelength spectrum,
• further modulating the light of respective ones of said spectral bands of said expanded, modulated beam of the wavelength spectrum in each of a plurality of parallel directions extending across said plurality of spectral bands of said expanded beam to alter said at least one property of the light by values corresponding to respective ones of a plurality of template wavelength spectra, wherein said values corresponding to each template wavelength spectrum of said plurality of template wavelength spectra are the conjugates of said representative values of said template spectrum of said template wavelength spectra.

In a method of multispectral imaging comprising the steps of producing spatial pictures of an image scene in a plurality of different spectral wavelength bands and utilizing differences in the observed spatial image at different wavelengths for detecting a feature of the scene, the improvement comprising simultaneously comparing a plurality of wavelength spectra observed for respective ones of a plurality of spatial pixels of a spatial picture of an image scene with at least one template wavelength spectrum to find a correlation, wherein said simultaneously comparing includes:

• modulating the light of respective ones of a plurality of spectral bands of each of said plurality of wavelength spectra to independently alter at least one property of the light by a representative value corresponding to the observed intensity of the corresponding wavelength spectrum in the respective spectral band,
• expanding a beam of the modulated light in a spatial dimension perpendicular to a direction of wavelength ordering of said wavelength spectra,
• further modulating the light of respective ones of said spectral bands of said expanded, modulated beam of the wavelength spectrum in each of a plurality of parallel directions extending across said plurality of spectral bands of said expanded beam to alter said at least one property of the light by values corresponding to at least one template wavelength spectrum, wherein said values corresponding to said at least one template wavelength spectrum are the conjugates of said representative values of said at least one template wavelength spectrum.