Contrast matching across spatial frequencies for isoluminant chromatic gratings.
Contrast matching was performed with isoluminant red-green and s-cone gratings at spatial frequencies ranging from 0.5 to 8 c/deg. Contrast threshold curves were low-pass in shape, in agreement with previous findings. Contrast matching functions resembled threshold curves at low contrast levels, but became flat and independent of spatial frequency at high contrasts. Thus, isoluminant chromatic gratings exhibited contrast constancy at suprathreshold contrast levels in a similar manner as has been demonstrated for achromatic gratings.
Tiippana
K
K
Helsinki University of Technology, Laboratory of Computational Engineering, PO Box 9400, 02015 HUT, Helsinki, Finland. kaisa.tiippana@hut.fi
Rovamo
J
J
Näsänen
R
R
Whitaker
D
D
Mäkelä
P
P
D003118:Color Perception / Q000502:physiology; D015350:Contrast Sensitivity / Q000502:physiology*; D004215:Distance Perception / Q000502:physiology; D005074:Evoked Potentials, Visual; D006801:Humans; D008432:Mathematical Computing; D010783:Photometry