Abstract

When red and green stimuli are alternated at some appropriate frequency, we perceive flicker. The flicker can be increased or decreased by changing the ratio of the two radiances; some particular ratio gives minimum flicker. When an adapting field of a certain color is applied, the ratio must be changed in order to obtain the minimum flicker, owing to selective chromatic adaptation. A red adapting field, for example, causes greater sensitivity loss for red compared to other spectral ranges. Thus the radiance ratio should be altered so as to increase the radiance of red stimulus over the green one. Factors HR and HG are introduced which specify the ratio change caused by the red and green adapting fields, respectively. A large HR is especially characteristic of normal color vision, and virtually zero HR is obtained for color defectives. Thus HR, in combination with HO, which specifies the radiance ratio with no adaptation, provides a new method of discriminating color defectives from normals and distinguishing types of defects. The present investigation shows that the discrimination among the three groups is very clear and that no misclassification occurs. However, dichromats are not distinguished from anomalous subjects; further investigation is needed concerning that point.

© 1968 Optical Society of America

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References

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  1. R. M. Boynton and M. Wagner, J. Opt. Soc. Am. 51, 429 (1961).
    [Crossref]
  2. Model I, Schmidt & Haensch.
  3. A type of 100-hue test manufactured by Nippon Shikisai Sha, Tokyo.
  4. Tokyo Medical College Color Vision Test, a set of pseudo-isochromatic plates, manufactured by Murakami Color Research Laboratory, Tokyo.
  5. R. M. Boynton and et al., J. Opt. Soc. Am. 55, 1672 (1965).
    [Crossref] [PubMed]

1965 (1)

1961 (1)

J. Opt. Soc. Am. (2)

Other (3)

Model I, Schmidt & Haensch.

A type of 100-hue test manufactured by Nippon Shikisai Sha, Tokyo.

Tokyo Medical College Color Vision Test, a set of pseudo-isochromatic plates, manufactured by Murakami Color Research Laboratory, Tokyo.

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Figures (9)

Fig. 1
Fig. 1

Principle of flicker HTRF.

Fig. 2
Fig. 2

Schematic view of the apparatus.

Fig. 3
Fig. 3

Difference HO plotted as a function of the wavelength of one stimulus, λ, while another stimulus is kept at 630 mμ for six subjects. Bottom figure: Normal subjects, MI (circles) and SN (triangles). Top figure: Color defectives, protanomalous TT (squares), protanope HM (circles), deuteranomalous MM (triangles), and deuteranope KI (crosses).

Fig. 4
Fig. 4

HR (upward) and Hμ (downward) vs λ, while another stimulus is kept at 630 mμ, from three normals, MI (circles), SN (triangles), and MU (crosses). HR is obtained with an adapting field of 630 mμ and 550 td and with the adapting field of μ, which is equal to λ and 550 td.

Fig. 5
Fig. 5

HR (circles) and HG (crosses) vs λ, while another stimulus is kept at 630 mμ, from four color defectives. HR is obtained with an adapting field of 630 mμ and 550 td and Hμ with the adapting field of μ, which is equal to λ, and 550 td.

Fig. 6
Fig. 6

Effect of the adapting luminance upon HR (upward) and HG (downward) for three normals, MI (circles), SN (triangles), and MU (crosses). The values at the extreme left indicate difference HO.

Fig. 7
Fig. 7

Effect of the adapting luminance upon HR and HG for deuteranomalous MM (triangles for HR and filled circles for HG), protanomalous TT (squares for HR and filled circles for HG), and six normals. Averaged values are plotted for six normals by open circles (HR) and crosses (HG).

Fig. 8
Fig. 8

HR and HG vs HO for six normals (circles), a deuteranomalous (triangles), and a protanomalous (squares) for the adapting level of 1000 td. Crosses are HR values for the same normals for an adapting level of 3200 td.

Fig. 9
Fig. 9

HOHR plot for normals (circles), deuteranomalous (open triangles), deuteranope (filled triangle), protanomalous (open squares), and protanopes (filled squares) for an adapting level of 1000 td.

Equations (3)

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HTRF = ( Δ R * R ) ( Δ G * G ) / ( Δ R * G ) ( Δ G * R ) ,
HTRF = { Δ R * R / Δ G * R } × { Δ G * G / Δ R * G } .
H = ( log Δ N R O - log Δ N G O ) + 2 log r .