Computation of cone contrasts for color vision research

Cole, Graeme R.; Hine, Trevor John

doi:10.3758/bf03203465

Cited by 69 publications

(36 citation statements)

References 20 publications

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“…Contrast is usually defined in luminance terms but, for our purpose we use cone excitation values instead, as is common in the literature (e.g., Weber cone contrast, Cole & Hine, 1992;Giulianini & Eskew, 1998;Michelson cone contrast, Gunther & Dobkins, 2002):…”

Section: Discussionmentioning

confidence: 99%

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Interactions between luminance and color signals: Effects on shape

2013

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Although luminance and color are thought to be processed independently at early stages of visual processing, there is evidence that they interact at later stages. For example, chromatic information has been shown to enhance or suppress depth from luminance depending on whether chromatic edges are aligned or orthogonal with luminance edges. Here we explored more generally how chromatic information interacts with luminance information that specifies shape from shading. Using a depth-matching task, we measured perceived depth in sinusoidal and square-wave gratings (specifying close-to sinusoidal and triangle-wave depth profiles, respectively) in three conditions. In the first, as we varied luminance contrast in the presence of an orthogonal chromatic grating, perceived depth increased (consistent with classical shape from shading). When we held the luminance at a fixed contrast and varied the chromatic grating in the other two conditions (orthogonal or aligned), we found large and inconsistent individual differences. Some participants exhibited the expected pattern of enhancement and suppression, but most did not, either for the sinusoidal or square-wave stimuli. Our results cast doubt on the idea that the interaction demonstrates a single high-level heuristic linked to depth perception. Instead, we speculate that interactions are more likely due to early cross-channel masking.

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Section: Discussionmentioning

confidence: 99%

“…Stimuli were created using the cone contrast space as defined by Cole, Hine, and McIlhagga (1993) and Cole and Hine (1992). Each of the three dimensions of this color space (Lc, Mc, Sc) is computed by dividing the cone intensity by the background intensity.…”

Section: Color Spacementioning

confidence: 99%

Interactions between luminance and color signals: Effects on shape

2013

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“…For each bandwidth, we calculated opponent channel output from the responses of the short-, medium-and long-wavelengthsensitive cones (S-, M-and L-cones, respectively) using the threshold model of Ingling & Tsou (1977). Cone excitations eii were determined from the equation below, in which i is cone type, j is bandwidth, Si(A) is cone spectral sensitivity, A is wavelength, and R (A) is stimulus spectral radiance (Cole & Hine, 1992).…”

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confidence: 99%

Red‐green opponent channel mediation of control of human ocular accommodation.

Kotulak

Morse

Billock

1995

The Journal of Physiology

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1. It has been hypothesized, but not verified empirically, that the control of human ocular accommodation is mediated by either the red‐green or yellow‐blue colour channels. Our goal was to determine experimentally whether the red‐green channel by itself could influence the accommodative response. 2. To find out, we isolated the red‐green channel through chromatic bandpass filtering and measured accommodation under dynamic and static conditions. The effect of this filtering was to modulate the red‐green channel without disturbing either the yellow‐blue or luminance channels. 3. Accommodative gain (ratio of response to stimulus amplitude) declined monotonically with decreasing bandwidth under dynamic conditions. Because the outputs of both the luminance and yellow‐blue colour channels did not vary with bandwidth, the only explanation is that the red‐green opponent process was responsible for the effect. 4. Under static conditions, however, accommodation was independent of bandwidth. This may be attributable to the decreased sensitivity to chromatic contrast that occurs at low temporal frequencies.

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“…The CIE (x, y, Y)-coordinates of the L-and M-cone isolating Sloan E stimulus at 23% was (0.385, 0.316, 11.5) and (0.234, 0.382, 10.8), respectively. Cone excitations were calculated from the CIE (1931) (x, y, Y) coordinates using Smith & Pokorny (1975) cone fundamentals based on transformations from Cole and Hine (1992) and Judd (1951) color matching functions. Relative (Weber) cone contrasts between the Sloan E and the background were calculated for each cone type (Cole & Hine, 1992).…”

Section: Perifoveal Measures Of Single Letter Visual Acuitymentioning

confidence: 99%

“…Cone excitations were calculated from the CIE (1931) (x, y, Y) coordinates using Smith & Pokorny (1975) cone fundamentals based on transformations from Cole and Hine (1992) and Judd (1951) color matching functions. Relative (Weber) cone contrasts between the Sloan E and the background were calculated for each cone type (Cole & Hine, 1992). The stimuli were displayed on a calibrated 22-inch CRT monitor (ViewSonic P227f, ViewSonic Corporation, Walnut CA, USA) via an nVidia Quadro FX2000 graphics card (NVIDIA Corporation, Santa Clara, CA, USA) at resolutions of: 30 bits per pixel spectral; 1600 Â 1200 pixels spatial; 100 Hz temporal.…”

Section: Perifoveal Measures Of Single Letter Visual Acuitymentioning

confidence: 99%

The relationship between perifoveal achromatic, L- and M-cone acuity and retinal structure as assessed with multimodal high resolution imaging

et al. 2017

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The relationships between perifoveal measures of achromatic-, L- and M-cone acuity and retinal structure were investigated in healthy young males. Thirty-two males, aged 20-39years, with normal foveal logMAR letter acuity and no observed ocular abnormalities participated in the study. Achromatic and isolated L- and M-cone spatial acuity was measured in the dominant eye with a Sloan E letter of 90% achromatic decrement contrast or 23% increment cone contrast, respectively. Separately, the central part of the same eye was imaged with high-resolution spectral-domain optical coherence tomography (SD-OCT) and adaptive optics ophthalmoscopy (AOO). Thickness measures and cone density in the fovea and parafoveal region were not correlated with perifoveal structural measures. A significant correlation was observed between thicker retinal pigment epithelium (RPE) complex, higher cone density and better L-cone logMAR at 5deg eccentricity, but not for achromatic or M-cone logMAR. The results imply that single letter perifoveal L-cone acuity, rather than achromatic acuity, may provide a useful measure for assessing the structure-function relationship and detecting early changes in the perifoveal cone mosaic.

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Computation of cone contrasts for color vision research

Cited by 69 publications

References 20 publications

Interactions between luminance and color signals: Effects on shape

Interactions between luminance and color signals: Effects on shape

Red‐green opponent channel mediation of control of human ocular accommodation.

The relationship between perifoveal achromatic, L- and M-cone acuity and retinal structure as assessed with multimodal high resolution imaging

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