A flaw in equations for predicting chromatic differences

Boynton, Robert M.; Nagy, Allen L.; Olson, Conrad X.

doi:10.1002/col.5080080203

Cited by 36 publications

(7 citation statements)

References 13 publications

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“…Differences in the genes encoding the cone pigments suggest that these two chromatic dimensions represent two subsystems of color vision that evolved at different times. 9 The LvsM and SvsLM axes differ from the principal axes implied by color appearance, and some measures of sensitivity point both to interactions between the two axes 10,11 and to further mechanisms tuned to intermediate color directions. 12 Yet along with luminance, the LvsM and SvsLM axes are thought to define the cardinal axes underlying early postreceptoral color coding.…”

Section: Introductionmentioning

confidence: 99%

Variations in normal color vision I Cone-opponent axes

et al. 2000

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Early postreceptoral color vision is thought to be organized in terms of two principal axes corresponding to opposing L- and M-cone signals (LvsM) or to S-cone signals opposed by a combination of L- and M-cone signals (SvsLM). These cone-opponent axes are now widely used in studies of color vision, but in most cases the corresponding stimulus variations are defined only theoretically, based on a standard observer. We examined the range and implications of interobserver variations in the cone-opponent axes. We used chromatic adaptation to empirically define the LvsM and SvsLM axes and used both thresholds and color contrast adaptation to determine sensitivity to the axes. We also examined the axis variations implied by individual differences in the color matching data of Stiles and Burch [Opt. Acta 6, 1 (1959)]. The axes estimated for individuals can differ measurably from the nominal standard-observer axes and can influence the interpretation of postreceptoral color organization (e.g., regarding interactions between the two axes). Thus, like luminance sensitivity, individual differences in chromatic sensitivity may be important to consider in studies of the cone-opponent axes.

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Section: Introductionmentioning

confidence: 99%

Variations in normal color vision I Cone-opponent axes

et al. 2000

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“…The colour-difference tolerances are frequently presented as contours of equal perceived (or accepted) differences from selected test colours plotted in a colour space such as Y , x , y space. These contours are assumed to be ellipsoidal in shape -not a very exact assumption, but accurate enough for most practical purposes (Boynton et al ., 1983). The contours are assumed elliptical for two dimensional spaces such as CIE chromaticity diagram.…”

Section: Ellipses and Ellipsoids Of Colour Discriminationmentioning

confidence: 99%

Colour-difference assessment

Choudhury

2015

Principles of Colour and Appearance Measurement

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“…We defined equivalent masks along the two axes in terms of multiples of threshold relative to the reference chromaticity. 24 Figure 1 shows a between-channels, backward masking example, where the violet-coloured noise mask follows the cherry-coloured target in time. The test sequence of targetblank-mask for backward masking or mask-blank-target for forward masking was embedded in 61 frames of temporal luminance noise, and the target was always presented in the center of the noise train.…”

Section: S166 Color Research and Applicationmentioning

confidence: 99%

Forward and backward masking with brief chromatic stimuli

Smithson¹,

Mollon²

2000

Color Res. Appl.

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Visual masking typically occurs when mask and target are separated in time by less than 100 ms, and the form of this interaction might be expected to depend on the latency of the target and mask signals. We track psychophysically the time course of signals from the two colouropponent channels by using forward and backward masking, in which mask and target each stimulate only one colour channel. Stimuli resemble those used in the Cambridge Colour Test, 1 in that spatial luminance noise is used to ensure that neither edge artifacts nor luminance differences can be used as a cue to discrimination of the stimulus against the field. Additionally, we introduce temporal luminance noise in order to ensure that our very brief chromatic modulations are not detected via the magnocellular pathway. Our data suggest that there is no large latency difference between the two chromatic channels of the early visual system, and that previous evidence for such a difference may instead reflect a difference between chromatic and achromatic pathways.

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A flaw in equations for predicting chromatic differences

Cited by 36 publications

References 13 publications

Variations in normal color vision I Cone-opponent axes

Variations in normal color vision I Cone-opponent axes

Colour-difference assessment

Forward and backward masking with brief chromatic stimuli

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