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Reevaluation of daylight spectral distributions
Author(s) -
Kránicz Balázs,
Schanda János
Publication year - 2000
Publication title -
color research and application
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.393
H-Index - 62
eISSN - 1520-6378
pISSN - 0361-2317
DOI - 10.1002/1520-6378(200008)25:4<250::aid-col5>3.0.co;2-d
Subject(s) - daylight , spectral power distribution , maxima and minima , interpolation (computer graphics) , maxima , mathematics , linear interpolation , spectral density , statistics , optics , mathematical analysis , computer science , physics , artificial intelligence , motion (physics) , art , performance art , polynomial , art history
The spectral power distribution of colorimetric daylight illuminants was determined based on measurements1 done some 40 years ago. The data were averaged and standardized at every full 10 nm. Later, to follow colorimetric practice, these data have been interpolated (linearly) to every 5 nm, but the factors to calculate the values have not been changed. We show in this article that this is not correct and leads to some discrepancies, especially if data with even smaller step size are required. We suggest that when correcting this discrepancy one should at the same time go from the linear interpolation technique, a rather crude method for a spectral distribution with many minor minima and maxima in the spectrum, to a nonlinear one. We show that a third‐order spline interpolation can provide smooth functions resembling the original data to a high degree. © 2000 John Wiley & Sons, Inc. Col Res Appl, 25: 250–259, 2000