A frequency view of colour: measuring the human sensitivity to square-wave spectral power distributions.
We have measured the chromatic threshold sensitivity to stimuli with spectral composition determined by a periodic function of energy over wavelength. This approach is analogous to frequency studies of spatial vision for the study of colour. A device was constructed permitting the synthesis of illuminants over the entire visible range (400-700 nm) in which phase, frequency and amplitude can be independently controlled. We have used 12 frequencies of square-wave functions (from 0.5 to 3.6 cycles/300 nm) and seven values of phase (between 0 degrees and 180 degrees) to obtain the contrast sensitivity function of the chromatic system in three normal trichromats. The results show maximum sensitivity around 1.5 cycles/300 nm and a high-frequency cut-off at 3.6 cycles/300 nm. These empirical values are compared with the predictions obtained from three current psychophysical models of opponent-colour process.
Institute of Neuroscience, CNRS-University of Paris VI, France.
V
V
Bonnardel
F J
FJ
Varela
D055592:Biophysical Phenomena; D001703:Biophysics; D003118:Color Perception / Q000502:physiology*; D015350:Contrast Sensitivity / Q000502:physiology; D006801:Humans; D008954:Models, Biological; D055095:Optics and Photonics; D010775:Photic Stimulation