The colors of natural scenes benefit dichromats

Pastilha, Ruben; Linhares, João M. M.; Gomes, Andreia Esteves; Santos, Jorge; Almeida, Vasco; Nascimento, Sérgio M. C.

doi:10.1016/j.visres.2019.02.003

Cited by 12 publications

(6 citation statements)

References 45 publications

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“…These abnormalities impact on CVD observers, reducing their colour discrimination performance . While colour vision normal (CVN) observers differentiate around 2 million colours 4 – 7 this number is reduced theoretically to as few as 7% (differentiating around 140,000 colours) in dichromatic CVD observers 8 , although for them, real world natural colours reveal higher degrees of discriminability 9 . A recent study simulating relative loss of colour discrimination in red-green CVD individuals highlights large differences between the impact of the CVD on perception in dichromacy versus in anomalous trichromacy, even when anomalous trichromacy is severe 10 .…”

Section: Introductionmentioning

confidence: 99%

Coloured filters can simulate colour deficiency in normal vision but cannot compensate for congenital colour vision deficiency

Álvaro

Linhares

Formankiewicz

et al. 2022

Sci Rep

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Red-green colour vision deficiency (CVD) affects ~ 4% of Caucasians. Notch filters exist to simulate CVD when worn by colour vision normal (CVN) observers (simulation tools), or to improve colour discrimination when worn by CVD observers (compensation tools). The current study assesses effects of simulation (Variantor) and compensation (EnChroma) filters on performance in a variety of tasks. Experiments were conducted on 20 CVN and 16 CVD participants under no-filter and filter conditions (5 CVN used Variantor; 15 CVN and 16 CVD used EnChroma). Participants were tested on Ishihara and Farnsworth-Munsell 100 hue tests, CVA-UMinho colour discrimination and colour naming tasks and a board-game colour-sorting task. Repeated-measures ANOVAs found Variantor filters to significantly worsen CVN performance, mimicking protanopia. Mixed-model and repeated-measures ANOVAs demonstrate that EnChroma filters do not significantly enhance performance in CVD observers. Key EnChroma results were replicated in 8 CVD children (Ishihara test) and a sub-sample of 6 CVD adults (CVA-UMinho colour discrimination and colour naming tasks) for a smaller stimulus size. Pattern similarity exists across hue for discrimination thresholds and naming errors. Variantor filters are effective at mimicking congenital colour vision defects in CVN observers for all tasks, however EnChroma filters do not significantly compensate for CVD in any.

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Section: Introductionmentioning

confidence: 99%

Coloured filters can simulate colour deficiency in normal vision but cannot compensate for congenital colour vision deficiency

Álvaro

Linhares

Formankiewicz

et al. 2022

Sci Rep

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“…Pastilha et al [23] evaluated the NODC through a psychophysical experiment to test the hypothesis that pairs of colors confused by dichromats are not frequent in natural scenes and therefore the visual impairment in natural environments is not as high as predicted by other studies [18]. Four normal trichromats and four dichromats (two protanopes and two deuteranopes) participated in the experiment and the results showed that the number of pairs discriminated by dichromats was around 70% of those discriminated by normal trichromats.…”

Section: Introductionmentioning

confidence: 99%

Spectral Filter Selection for Increasing Chromatic Diversity in CVD Subjects

Martínez-Domingo

Valero

Gómez‐Robledo

et al. 2020

Sensors

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This paper analyzes, through computational simulations, which spectral filters increase the number of discernible colors (NODC) of subjects with normal color vision, as well as red-green anomalous trichromats and dichromats. The filters are selected from a set of filters in which we have modeled spectral transmittances. With the selected filters we have carried out simulations performed using the spectral reflectances captured either by a hyperspectral camera or by a spectrometer. We have also studied the effects of these filters on color coordinates. Finally, we have simulated the results of two widely used color blindness tests: Ishihara and Farnsworth-Munsell 100 Hue (FM100). In these analyses the selected filters are compared with the commercial filters from EnChroma and VINO companies. The results show that the increase in NODC with the selected filters is not relevant. The simulation results show that none of these chosen filters help color vision deficiency (CVD) subjects to pass the set of color blindness tests studied. These results obtained using standard colorimetry support the hypothesis that the use of color filters does not cause CVDs to have a perception similar to that of a normal observer.

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“…When the chromatic component was effectively removed, leaving only lightness information, estimated losses increased by three to four times. The limitations of lightness information were previously noted in an experiment 33 where dichromatic observers discriminated real three-dimensional objects whose spectral reflectances had the same frequencies of occurrence as in some of the scenes in this analysis.…”

Section: Discussionmentioning

confidence: 64%

“…Encouragingly, the estimate for dichromats of effectively about one-third fewer distinguishable surfaces (average data from Figure 2 , top panel) is similar to a reduction in dichromatic observers’ experimental discrimination of object spectral reflectances with natural frequencies of occurrence. 33 …”

Section: Discussionmentioning

confidence: 99%

“…In yet other tasks, red-green color vision deficiency has been found to have less effect than expected on the discrimination of objects with spectral reflectances drawn from natural scenes, 32 once their frequencies of occurrence are accounted for. 11 , 33 It also has little effect on the judgment of the constancy of surface colors under different lights (illuminant color constancy) with surface spectral reflectances drawn from the approximately perceptually uniform Munsell Book of Color 34 , 35 , 36 or from natural scenes. 35 , 37 , 38 , 39 It additionally has little or no effect on memory for colored scenes 40 or on discriminating typical illumination changes.…”

Section: Introductionmentioning

confidence: 99%

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