Patent ID: 7944557

Claim:
An encoded filter-correlation radiometer for measuring a sample, comprising: at least one source providing broad-band radiation in at least one spectral range; a two dimensional spatial radiation modulator optically coupled to the at least one source, rotated about a rotation axis, and positioned in a plane so that an encoding axis of said modulator is substantially along a radial axis of said modulator, said modulator having at least three radiation encoding filters at different radii from said rotation axis for modulating intensities of radiation from said source as said modulator is rotated about said rotation axis; optics for collecting and directing radiation to the modulator so that said radiation forms at least three sub-images along a radial axis of the modulator, said sub-images modulated by said radiation encoding filters to provide a modulated beam; a detector for providing an output in response to the modulated beam; and a computer for analyzing signals generated by said detector in response to said modulated beam to measure characteristics of the sample; wherein the at least one source is optically coupled via an optical path from the at least one source through the optics and the modulator to the detector, wherein the optical path also comprises the following in any order anywhere along the optical path except for between the optics and the modulator: at least two target wavelength filters, each said target wavelength filter having substantial optical transmission attenuation in said spectral range, said optical transmission attenuation a function of one or more spectral properties of a corresponding target analyte in a sample; at least one reference wavelength filter, said reference filter having substantially less optical transmission attenuation in said spectral range as compared to said target wavelength filter; and a sample comprising at least one target analyte.