TESTING LINEAR-MODELS ON SPECTRAL DAYLIGHT MEASUREMENTS

We have analyzed the results of the reconstruction quality of 252 dayl ight spectral curves measured at Granada, Spain, using four bases obta ined from measurements in different areas of the world. For these reco nstructions we used two different methods (orthogonality of characteri stic vectors and chromaticity coordinates) to study the influence of t he wavelength range and spectral resolution. The reconstruction method from chromaticity coordinates presents difficulties for the spectral recovery of daylight spectral power distributions regardless of the ba sis used. The orthogonality method makes clear that the best bases wer e those proposed by the CIE, but more than two characteristic CIE vect ors were needed for good. (C) 1998 Optical Society of America.