Temporal summation of moving images by the human visual system
- 11 March 1981
- journal article
- research article
- Published by The Royal Society in Proceedings of the Royal Society of London. B. Biological Sciences
- Vol. 211 (1184), 321-339
- https://doi.org/10.1098/rspb.1981.0010
Abstract
Measurements of threshold visibility were made as a function of duration of stimulus exposure for small moving dot targets, drifting sinusoidal gratings and moving patches of sinusoidal gratings to investigate how the human visual nervous system summates over time signals arising from stimuli in motion. At image speeds of < 16 degree/s, temporal summation is as strong and as extended for moving as for stationary dots (total summation over to about 100 ms). This summation is about twice that which would be expected from separate consideration of the regions of spatial and temporal integration. Measurements with sinusoidal gratings reveal that the nature of the summation critically depends on the spatial frequency of the stimulus: gratings of low spatial frequency summate well when in motion (and only when in motion); those of high spatial frequency summate well only when stationary or in very slow motion. An analog simulation with electronic filters showed that these psychophysical results are directly predictable from the known transfer characteristics of the human visual system (with the additional assumption of probability summation at threshold). With small patches of sinusoidal grating, it was established that translation per se across the retina has little effect on temporal summation. Apparently, the results obtained with sinusoidal gratings of a large extent are also relevant to small moving stimuli, allowing the summation results obtained with dot stimuli to be discussed in terms of the temporal transfer properties of spatially selective visual detectors. It is proposed that the extended temporal summation observed for dots in motion results from summation of energy of low spatial frequency present in these stimuli.Keywords
This publication has 21 references indexed in Scilit:
- Motion smearNature, 1980
- Sensitivity to spatial phaseVision Research, 1980
- Stopped visual motionNature, 1979
- Channels in Vision: Basic AspectsPublished by Springer Nature ,1978
- Grating summation in fovea and peripheryVision Research, 1978
- The functional area for summation to threshold for sinusoidal gratingsVision Research, 1978
- Spatial and Temporal Contrast-Sensitivity Functions of the Visual SystemJournal of the Optical Society of America, 1966
- Temporal Summation of Positive and Negative Flashes in the Visual System*Journal of the Optical Society of America, 1965
- Study of Interrelations between Mechanisms at Threshold*Journal of the Optical Society of America, 1963
- Relationship between Critical Flicker-Frequency and a Set of Low-Frequency Characteristics of the EyeJournal of the Optical Society of America, 1954