If two different surfaces look the same when viewed under a particular light source, then they are called metamers. We show mathematically how one can solve for the whole set of physically realizable natural surface reflectances that relate to the same tristimulus, the metamer set. Our analysis is based on very general linear models of reflectances, coupled with constraints that reflectances should adhere to (e.g., positivity and boundedness). We show that we can recover metamer sets for linear models of an arbitrary high dimension. To illustrate our new algorithm, we provide an example of calculating the metamer set and its manifestation as a mismatch region. Given a single XYZ observed under illuminant D65, we can examine the set of XYZs that would be possible under illuminant A.
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http://dx.doi.org/10.1364/josaa.22.000810 | DOI Listing |
J Vis
November 2021
School of Computing Science, Simon Fraser University, Vancouver, BC, Canada.
Color difference sensitivity as represented by the size of discrimination ellipsoids is known to depend on where the colors reside within color space. In the past, various color spaces and color difference formulas have been developed as parametric fits to the experimental data with the goal of establishing a color coordinate system in which equally discriminable colors are equal distances apart. These empirical models, however, provide no explanation as to why color discrimination varies in the way it does.
View Article and Find Full Text PDFMetamer mismatching is a phenomenon where two objects that are colorimetrically indistinguishable under one lighting condition become distinguishable under another one. Due to the unavailability of spectral information, metamer mismatching introduces an inherent uncertainty into cameras' color reproduction. To investigate the degree of image quality degradation by the metamer mismatching, a large spectral reflectance database was compiled in this study to search the object-color metamers sets of the spectra in hyperspectral images.
View Article and Find Full Text PDFJ Opt Soc Am A Opt Image Sci Vis
July 2014
Solid state lighting is becoming a popular light source for color vision experiments. One of the advantages of light emitting diodes (LEDs) is the possibility to shape the target light spectrum according to the experimenter's needs. In this paper, we present a method for creating metameric lights with an LED-based spectrally tunable illuminator.
View Article and Find Full Text PDFSeeing Perceiving
August 2012
Department of Vision Sciences, Glasgow Caledonian University, Cowcaddens Road, Glasgow G4 0BA, UK.
Although asymmetric colour matching has been widely used in experiments on colour constancy, an exact colour match between objects lit by different chromatic lights is impossible to achieve. We used a modification of this technique, instructing our observers to establish the least dissimilar pair of differently illuminated coloured papers. The stimulus display consisted of two identical sets of 22 Munsell papers illuminated independently by neutral, yellow, blue, green and red lights.
View Article and Find Full Text PDFProc IEEE Int Symp Biomed Imaging
April 2010
Center for Biomedical Imaging and Informatics, The Cancer Institute of NJ, UMDNJ-RWJMS.
A multispectral camera is capable of imaging a histologic slide at narrow bandwidths over the range of the visible spectrum. There is currently no clear consensus over the circumstances in which this added spectral data may improve computer-aided interpretation and diagnosis of imaged pathology specimens [1, 2, 3]. Two spectra which are perceived as the same color are called metamers, and the collection of all such spectra are referred to as the metamer set.
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