Temporal summation of moving images by the human visual system

1981 ◽  
Vol 211 (1184) ◽  
pp. 321-339 ◽  
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Temporal Summation ◽  
Temporal Integration ◽  
High Spatial Frequency ◽  
Slow Motion ◽  
Sinusoidal Grating ◽  
Moving Images ◽  
Sinusoidal Gratings

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 less that 16 deg/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 depends critically on the spatial frequency of the stimulus: gratings of low spatial frequency summate well when in motion (and only when in motion), whereas those of high spatial frequency summate well only when stationary or in very slow motion. An analogue 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). Finally, with small patches of sinusoidal grating, it was established that translation per se across the retina has little effect on temporal summation. This suggests that the results obtained with sinusoidal gratings of 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. On the basis of these results 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.

Dynamics of Adaptation to Contrast

Perception ◽  
1982 ◽  
Vol 11 (5) ◽  
pp. 505-528 ◽  
Author(s):  
David Rose ◽  
Ivan Lowe
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Power Function ◽  
Single Phase ◽  
Detection Threshold ◽  
High Spatial Frequency ◽  
Sinusoidal Grating ◽  
Dual Phase ◽  
High Contrast ◽  
Inhibitory Interactions

An investigation has been made into the temporal parameters with which the detection threshold for a sinusoidal grating changes during and after adaptation to the same grating at high contrast. Stationary high-spatial-frequency gratings and a phase-reversing low-spatial-frequency grating have been studied separately. It was found that the threshold continues to rise during adaptation for at least 6 min without sign of levelling off, and that full recovery from 6 min of adaptation can take more than 45 min. Intermittent adaptation and continuous adaptation for the same period produce similar effects. Single-phase and dual-phase exponential fits to the data are rejected, and it is concluded that the level of adaptation of the visual system to spatial contrast changes as a power function of time. However, recovery is not always monotonic, especially after adaptation to phase-reversing gratings. This may be due to inhibitory interactions between channels (in particular, those for pattern and movement information).

Evidence on the local character of spatial frequency channels in the human visual system

1985 ◽  
Vol 25 (9) ◽  
pp. 1233-1240 ◽  
Author(s):  
Eckart Perizonius ◽  
Wolfgang Schill ◽  
Hans Geiger ◽  
Rainer Röhler
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Local Character

Temporal-Discontinuity Detection with Contrast-Modulated Gratings

Perception ◽  
1995 ◽  
Vol 24 (11) ◽  
pp. 1257-1264
Author(s):  
Shigeru Ichihara ◽  
Kenji Susami
Keyword(s):  
Spatial Frequency ◽  
Modulation Frequency ◽  
Sinusoidal Grating ◽  
Local Contrast ◽  
Staircase Method ◽  
Low Contrast ◽  
Discontinuity Detection ◽  
Temporal Discontinuity ◽  
Sinusoidal Gratings ◽  
The Subject

Three experiments on temporal-discontinuity detection were carried out. In experiment 1, temporal-discontinuity thresholds were measured for sinusoidal gratings by the use of the double-staircase method. A sinusoidal grating was presented twice successively. The subject judged whether or not an interval was present. The temporal-discontinuity threshold increased as the spatial frequency of the grating increased, but decreased as the contrast of the grating increased. In experiment 2, contrast-modulated gratings were used instead of the sinusoidal grating. The temporal-discontinuity threshold increased as the carrier frequency increased, and the threshold for each contrast-modulated grating was similar to that for the no-modulation (sinusoidal) grating whose contrast was the same as the maximum local contrast of the contrast-modulated grating. In experiment 3, temporal-discontinuity thresholds were measured for low-contrast (3%) sinusoidal gratings. The thresholds were very low, even for such low-contrast gratings. These results suggest that the low-spatial-frequency channels are not involved in detecting the modulation frequency of the contrast-modulated grating. Rather, the local contrast seems to be the determinant of the detection of the contrast-modulated grating itself.

The Study of Spatial Frequency Channels for Human Visual System

2019 ◽  
Vol 33 (06) ◽  
pp. 1955007
Author(s):  
Xiangyang Xu ◽  
Qiao Chen ◽  
Ruixin Xu
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Frequency Tuning ◽  
Tuning Curve ◽  
Vision System ◽  
Human Vision ◽  
Psychophysical Experiment ◽  
Human Vision System

Similar to auditory perception of sound system, color perception of the human visual system also presents a multi-frequency channel property. In order to study the multi-frequency channel mechanism of how the human visual system processes color information, the paper proposed a psychophysical experiment to measure the contrast sensitivities based on 17 color samples of 16 spatial frequencies on CIELAB opponent color space. Correlation analysis was carried out on the psychophysical experiment data, and the results show obvious linear correlations of observations for different spatial frequencies of different observers, which indicates that a linear model can be used to model how human visual system processes spatial frequency information. The results of solving the model based on the experiment data of color samples show that 9 spatial frequency tuning curves can exist in human visual system with each lightness, R–G and Y–B color channel and each channel can be represented by 3 tuning curves, which reflect the “center-around” form of the human visual receptive field. It is concluded that there are 9 spatial frequency channels in human vision system. The low frequency tuning curve of a narrow-frequency bandwidth shows the characteristics of lower level receptive field for human vision system, the medium frequency tuning curve shows a low pass property of the change of medium frequent colors and the high frequency tuning curve of a width-frequency bandwidth, which has a feedback effect on the low and medium frequency channels and shows the characteristics of higher level receptive field for human vision system, which represents the discrimination of details.

Selective Adaptation to Low Spatial Frequencies Does Not Decrease the Mueller-Lyer Illusion

1994 ◽  
Vol 78 (1) ◽  
pp. 339-347
Author(s):  
Janet D. Larsen ◽  
Beth Anne Goldstein
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Major Part ◽  
Selective Adaptation ◽  
Sinusoidal Grating ◽  
Square Wave ◽  
Frequency Information ◽  
Lyer Illusion ◽  
Spatial Frequencies

The idea that low spatial-frequency information in the Mueller-Lyer figure accounts for a major part of the illusion was tested in a series of five studies. In Study 1, subjects were selectively adapted to high or low square-wave spatial-frequency gratings with no difference in the magnitude of illusion they experienced. Similarly, adaptation to sinusoidal grating patterns with either high or low spatial frequency had no effect on the magnitude of illusion experienced (Studies 2 to 5). The failure of adaptation to low spatial-frequency gratings to affect the magnitude of illusion experienced indicates either that the illusion cannot be accounted for by the low spatial-frequency information or that adaptation of the visual system by grating patterns cannot be used to explore any effects of the low spatial frequencies in the figure.

A Test of the Spatial-Frequency Explanation of the Müller-Lyer Illusion

Perception ◽  
1986 ◽  
Vol 15 (5) ◽  
pp. 553-562 ◽  
Author(s):  
Marisa Carrasco ◽  
Jesus G Figueroa ◽  
J Douglas Willen
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Lyer Illusion ◽  
Lower Spatial Frequency ◽  
Spatial Frequencies ◽  
Frequency Components ◽  
Fourier Spectra

Previous investigations have shown that the response of spatial-frequency-specific channels in the human visual system is differentially affected by adaptation to gratings of distinct spatial frequencies and/or orientations. A study is reported of the effects of adaptation to vertical or horizontal gratings of a high or a low spatial frequency on the extent of the Brentano form of the Müller-Lyer illusion in human observers. It is shown that the illusion decreases after adaptation to vertical gratings of low spatial frequency, but seems unaffected otherwise. These results are consistent with the notion of visual channels that are spatial-frequency and orientation specific, and support the argument that the Müller-Lyer illusion may be due primarily to lower-spatial-frequency components in the Fourier spectra of the image.

scholarly journals The Human Visual System Whitens in Space But Not in Spatial Frequency

2020 ◽  
Vol 20 (11) ◽  
pp. 425
Author(s):  
Anqi Zhang ◽  
Wilson S. Geisler
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System

Dark Adaptation as a Model of the Parkinsonian Visual System

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 48-48
Author(s):  
B Wink ◽  
J P Harris
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Dark Adaptation ◽  
Peripheral Vision ◽  
Receptive Fields ◽  
High Spatial Frequency ◽  
Normal Subjects ◽  
Apparent Contrast ◽  
Contrast Gain ◽  
Spatial Frequencies

It has been suggested that the Parkinsonian visual system is like the normal visual system, but is inappropriately dark-adapted (Beaumont et al, 1987 Clinical Vision Sciences2 123 – 129). Thus it is of interest to ask to what extent dark adaptation of normal subjects produces visual changes like those of Parkinson's disease (PD). One such change is the reduction in apparent contrast of medium and high spatial frequencies in peripheral vision in the illness (Harris et al, 1992 Brain115 1447 – 1457). Normal subjects judged whether the contrast of a peripherally viewed grating was higher or lower than that of a foveally viewed grating, and a staircase technique was used to estimate the point of subjective equality. Judgements were made at four spatial frequencies (0.5 to 4.0 cycles deg−1) and four contrasts (8.0% to 64%). The display, the mean luminance of which was 26 cd m−2, was viewed through a 1.5 lu nd filter in the relatively dark-adapted condition. The ANOVA showed an interaction between dark adaptation and the spatial frequency of the gratings. Dark adaptation reduces the apparent contrast of high-spatial-frequency gratings, an effect which is greater at lower contrasts. This mimics the effect found with PD sufferers, and suggests that dark adaptation may provide a useful model of the PD visual system. In a second experiment, the effect of dark adaptation on the relationship between apparent spatial frequency in the fovea and periphery was investigated. The experiment was similar to the first, except that judgements were made about the apparent spatial frequency, rather than the contrast, of the peripheral grating. ANOVA showed no differential effect of dark adaptation on the apparent spatial frequency of the peripheral grating. This suggests that the observed reduction in apparent contrast of the peripheral gratings in dark-adapted normals and Parkinson's sufferers may reflect relative changes in contrast gain, rather than relative changes in the spatial organisation of receptive fields.

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