Optical spectral analysis apparatus

Optical spectral analysis apparatus for measurements of optical properties of a sample which comprises a plurality of sources of radiant energy, a plurality of devices for the conversion of radiant energy in to electrical signals, means in each of said sources for providing a spectrum of energy with reference to wavelength which said spectrum is different from said spectrum of the others of said sources, means in each of said devices for providing a response to radiant energy as a function of wavelength which differs from the response to radiant energy for each of the others of said devices, and means for operating said apparatus by first providing electrical energy to each said source of radiant energy, for each of distinct periods of time during which said periods of time at least one of the other sources of radiant energy is not provided with electrical energy, and second allowing or directing radiant energy produced by said sources to interact with the sample in such a fashion that some radiant energy reflected from and/or transmitted by and/or emitted by said sample is returned to said devices, and third recording the electrical signals from each said device for the conversion of radiant energy to electrical signal output during each such said period of time, and fourth calculating from each said recorded electrical signal output a value which is a weighted integration of radiant energy over wavelength, thus producing a set of said weighted integration values whose number is equal to the product of the number of said distinct time periods with the number of said devices for the conversion of radiant energy to electrical signal, and fifth calculating from said set of weighted integration values said set of multiple measurements by linear transformation of said set of weighted integration values utilizing predetermined coefficients for transformation.