Systems and methods for determining spectra using dynamic least squares algorithms with measurements from LED color sensor

摘要

A spectral determination system, comprising a plurality of illuminants; at least one photodetector that detects light originating from the plurality of illuminants and reflected by a target; and a controller that: normalizes a plurality of illuminant sensor outputs obtained from the at least one photodetector, each illuminant sensor output indicating a reflectance value obtained from a target; obtains reference data from a reference database that correlates reference spectra with a corresponding plurality of normalized illuminant sensor outputs, the reference data including data in a neighborhood of each reflectance value; and determines a spectrum Ŝ based on the illuminant sensor outputs and the reference data, wherein the determining step places greater importance on the data in the neighborhood of each reflectance value, wherein the controller performs the determining step based on linear operators, and wherein the linear operators are represented by Ci=Zi⁢Bibi=wi+Ci⁢ZiTB⁢i+1=Bi-C⁢iT⁢Ci/biD⁢i+1=Di+SiT⁢Zi/wiwhere w(i) represents a weighting function that places greater importance on the data in the neighborhood of each actual reflectance value, Si is an ith reference spectrum in the reference database, and Zi is an ith normalized illuminant sensor output in the reference database, the linear operators being recursively computed until i = N, where N is a number of spectral samples in the reference database.