Abstract

New methods for the measurement of flicker heterochromatic threshold-reduction factor are introduced. In one method, a test stimulus is composed of two fields presented side by side. In each field, red and green lights are alternated at the test frequency. The ratios of luminances of the two colors in the respective fields are kept slightly different. When a subject sees the test stimulus, he can easily decide which field shows more flicker. The ratio can be altered by rotating two circular neutral-density wedges inserted in the two fields and coupled so that they rotate in opposite directions by the same amounts. With this arrangement, we employ the constant-stimuli method. Pairs of stimuli with different ratios are presented and the subject judges which of the two fields exhibits the stronger appearance of flicker. We determine the wedge settings for which the probability of a given degree of flicker is the same for both fields. The method of adjustment can also be used, in which the subject adjusts the wedge setting so as to match the flicker appearance of both fields. The above arrangement was modified so that the subject saw 13 fields lined up horizontally. Each field had a different ratio of red and green light. The subject determined which field was least flickering. All of these methods are useful for measuring the flicker heterochromatic threshold-reduction factor.

© 1971 Optical Society of America

Theory and Experiments Concerning the Heterochromatic Threshold-Reduction Factor (HTRF)*

Robert M. Boynton, Horst Scheibner, Terry Yates, and Edward Rinalducci
J. Opt. Soc. Am. 55(12) 1672-1685 (1965)

Two-band model of heterochromatic flicker

D. H. Kelly and D. van Norren
J. Opt. Soc. Am. 67(8) 1081-1091 (1977)

Flicker HTRF as Test of Color Vision

Mitsuo Ikeda and Mitsuo Urakubo
J. Opt. Soc. Am. 58(1) 27-31 (1968)

Luminance Thresholds for Subjective Patterns in a Flickering Field: Effect of Wavelength*

Arnulf Remole
J. Opt. Soc. Am. 61(9) 1164-1168 (1971)

Minimally Distinct Border as a Preferred Psychophysical Criterion in Visual Heterochromatic Photometry*

Peter K. Kaiser
J. Opt. Soc. Am. 61(7) 966-971 (1971)