High-contrast luminance gratings stabilized on the retina with a Purkinje image eyetracker do not disappear completely. This could be due to small errors of stabilization, or the visual system could include mechanisms capable of responding to temporally constant images. We examined the visual system’s sensitivity to small movements of gratings. We (1) replicated previous measurements of contrast sensitivity for gratings with controlled retinal-drift velocities, (2) developed a method for calculating sensitivity to small oscillations of gratings using thresholds for flickering stabilized gratings, and (3) examined the calculations empirically. We calculated that movements of only 8 sec of arc peak to peak produce detectable temporal changes. Since existent stabilization systems cannot eliminate movements this small, residual stabilized-grating detectability does not require detectors sensitive to temporally constant images.
© 1986 Optical Society of America
Original Manuscript: January 30, 1985
Manuscript Accepted: September 16, 1985
Published: February 1, 1986
Lawrence E. Arend and George T. Timberlake, "What is psychophysically perfect image stabilization? Do perfectly stabilized images always disappear?," J. Opt. Soc. Am. A 3, 235-241 (1986)