December 2019
Volume 19, Issue 15
Open Access
OSA Fall Vision Meeting Abstract  |   December 2019
Breaking illuminant metamerism using directional spectral variation in natural environments: dichromats might benefit more than trichromats
Author Affiliations
  • Takuma Morimoto
    Department of Experimental Psychology, University of Oxford, UK
  • João M.M. Linhares
    Center of Physics, University of Minho, Campus de Gualtar, Portugal
  • Sérgio M.C. Nascimento
    Center of Physics, University of Minho, Campus de Gualtar, Portugal
  • Hannah E. Smithson
    Department of Experimental Psychology, University of Oxford, UK
Journal of Vision December 2019, Vol.19, 9. doi:https://doi.org/10.1167/19.15.9
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Takuma Morimoto, João M.M. Linhares, Sérgio M.C. Nascimento, Hannah E. Smithson; Breaking illuminant metamerism using directional spectral variation in natural environments: dichromats might benefit more than trichromats. Journal of Vision 2019;19(15):9. doi: https://doi.org/10.1167/19.15.9.

      Download citation file:


      © ARVO (1962-2015); The Authors (2016-present)

      ×
  • Supplements
Abstract

Illuminant metamerism, where two surfaces appear the same under one illuminant but different under another, has been thought to limit object identification by colour, especially for dichromats, who possess only two classes of cones. The frequency of metamerism has typically been evaluated using surfaces placed under single-spectrum illumination. However, we recently showed that there is a striking directional variation of illuminant spectra in natural lighting environments [1], meaning that a surface will sample different spectra depending on its angle within the environment. Therefore, observers might be able to disambiguate some metameric pairs simply by tilting the surface. We simulated a tiltable matte planar surface using computer-graphics rendering techniques and analyzed the frequency of metameric pairs drawn from a standard object colour spectra database of 53,486 reflectances (SOCS). The results suggest that trichromats can break 33.4% (average across 12 scenes) of metamers simply by tilting the surface. Dichromats can break a similar proportion (deutan: 34.4%, protan: 36.0%, tritan: 30.4%). After removing very similar spectra from the sample (correlation coefficient >.99), trichromats can break 50.6% of metameric pairs. Tritans can break a similar proportion (55.3%) while protans and deutans can break significantly more (56.5% and 58.1%, respectively). Several studies have reported that illuminant metamerism is relatively rare. Here, using newly available measures of the spectral variation in natural lighting environments, we suggest that roughly half these metamers can be disambiguated. In addition, under these conditions, protan and deutan object identification by colour is relatively less impaired compared to the trichromatic case.

Morimoto T. Kishigami S. Linhares J. M.M. Nascimento S.M.C. Smithson H. E. “Hyperspectral environmental illumination maps: Characterizing directional spectral variation in natural environments” bioRxiv660290, https://doi.org/10.1101/66029(2019)
Footnotes
 This study was supported by a Study Visit grant from the Experimental Psychology Society, UK, awarded to TM and by the Portuguese Foundation for Science and Technology (FCT) in the framework of the Strategic Funding UID/FIS/04650/2019 awarded to SN.
×
×

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.

×