title: Images perceived after chromatic or achromatic contrast sensitivity losses.
abstract: OBJECTIVE
  We simulate how subjects with losses in chromatic and achromatic contrast sensitivity perceive colored images by using the spatiochromatic corresponding pair algorithm.
  
  
  METHODS
  This is a generalized version of the algorithm by Capilla et al. (J Opt Soc Am (A) 2004;21:176-186) for simulating color perception of color deviant subjects, which incorporates a simple spatial vision model, consisting of a linear filtering stage, with a band-pass achromatic filter and two low-pass chromatic ones, for the red-green and blue-yellow mechanisms. These filters, except for the global scaling, are the subject's contrast sensitivity functions measured along the cardinal directions of the color space. In its present form, the algorithm would serve to simulate alterations both in the spectral sensitivities and in the contrast sensitivities of the visual mechanisms.
  
  
  RESULTS
  After a preliminary theoretical study on the effect of frequency selective and overall reductions in the contrast sensitivity function of a single mechanism, we present cases of real subjects with glaucoma and diabetes, suffering alterations of different magnitude in the three mechanisms.
  
  
  CONCLUSIONS
  The simulations allow us to learn about the different types of distortions that can be experienced by a subject with impaired contrast sensitivities (blur, haloes, color shifts, local or global contrast, brightness and colorfulness reductions, etc.) and highlight the difficulties arising when trying to predict the quality of the final image from the losses in the individual mechanisms.
authors.affiliation: Departament d'Optica, Universitat de València, València, Spain.
authors.forename: M José
authors.initials: MJ
authors.lastname: Luque
authors.forename: Pascual
authors.initials: P
authors.lastname: Capilla
authors.forename: M Dolores
authors.initials: MD
authors.lastname: de Fez
authors.forename: M Carmen
authors.initials: MC
authors.lastname: García-Domene
mesh_terms: D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology*; D006801:Humans; D008029:Lighting; D008433:Mathematics; D008959:Models, Neurological; D010364:Pattern Recognition, Visual / Q000502:physiology*; D012165:Retinal Ganglion Cells / Q000502:physiology