Ülker Tulunay-Keesey’s research while affiliated with University of Wisconsin–Madison and other places

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Publications (7)


Adaptation with a stabilized retinal image: Effect of luminance and contrast
  • Article

December 1994

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17 Reads

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6 Citations

Vision Research

Jesse D. Olson

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Ülker Tulunay-Keesey

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The addition of a uniform increment of luminance (L) to a faded retinally-stabilized target results in the subjective reappearance of the image with contrast opposite to that of the target. This phenomenon, called apparent phase reversal (APR), reveals a nonlinear gain mechanism in the adaptation process. The magnitude of the threshold increment to elicit APR (Lapr) is a measure of the state of stabilized adaptation. In the experiments reported here, Lapr was studied as a function of background luminance (Lo) and contrast (m) of the adapting stimulus. It was found that Lapr increases with increasing Lo, but does not depend on m. The data are analyzed within the context of a previously proposed model of stabilized image fading consisting of a multiplicative inverse gain followed by a subtractive process. It was found that the addition of a contrast processing stage was required to account for the relationship between Lapr and m.


Fading time of retinally-stabilized images as a function of background luminance and target width

November 1993

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15 Reads

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11 Citations

Vision Research

Fading time of a retinally-stabilized difference-of-Gaussian (DOG) stimulus depends on the background luminance, contrast and spatial frequency content of the stimulus. A model of the visual system including a nonlinear multiplicative, non-local and fast process followed by a linear subtractive, local and slower process accounts for these effects. Analysis of the fading time data allows us to estimate the spatiotemporal characteristics of the proposed adaptation processes. The model is consistent with recent models of normal light adaptation from the probe-flash paradigm.


(A) Thresholds for detecting an off-image (dotted line) and a real-light image (solid line) in stabilized vision. (B) Contrast thresholds for detecting real-light (solid line) image and an off-image (dotted line) in unstabilized, normal vision. For the method used to obtain the off-image, see the text.
Time it takes for a stabilized image to disappear as a function of contrast. Contrast for each spatial frequency is expressed as multiples of its own threshold level. There was a 20-sec limit imposed on viewing time; for 18 cpd, 10 and 15 times contrast were not used.
(A) Time to disappearance of an off-image produced by a stabilized inducing target as a function of inducing contrast. (B) Time to disappearance of an off-image produced by a normally viewed, unstabilized inducing target as a function of inducing contrast. The inducing targets were presented for 10 sec.
(A) Time to disappearance of an off-image produced by an unstabilized inducing target (squares and solid line), a stabilized inducing target (open circles and dotted line), and a real-light stabilized image (filled circles and dotted line) as a function of spatial frequency. All were at threshold level. (B) Time to disappearance of off-images (squares and solid line for the unstabilized inducing, circles and dotted line for stabilized inducing targets) and the real-light stabilized image (filled circles and dotted lines) as a function of spatial frequency. The inducing image and the real-light image were at contrast levels five times their threshold.
(A) Time to disappearance as a function of spatial frequency of off-images produced by a stabilized inducing target (open circles and dotted line) compared with the disappearance of real-light stabilized images of equivalent contrast (filled circles and dotted line); (B) Time to disappearance as a function of spatial frequency of off-images produced by a normally viewed unstabilized inducing target (squares and solid line) and stabilized real-light targets of equivalent contrast (filled circles and dotted line).

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Fading of stabilized retinal images
  • Article
  • Publisher preview available

April 1982

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54 Reads

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52 Citations

Journal of the Optical Society of America

It is well known that targets whose images are stabilized on the retina by optical means, as well as afterimages that are naturally stabilized on the retina, fade and eventually disappear. Comparative data are presented on the rate of disappearance of stabilized images and afterimages as a function of contrast and spatial frequency. The main finding is that they disappear in a similar fashion only when target contrast is low.

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Percent contrast necessary to evoke an afterimage in stabilized viewing as a function of spatial frequency. Solid lines represent data obtained in our laboratory with observer BJB, UTK, and RMJ. The (*) represents the highest frequency that produced an afterimage for all three subjects. This also was the highest frequency available with our display unit. The method for obtaining these measures was as follows: The observer viewed a given spatial frequency and contrast grating for 10 s. Only the onset of the pattern was marked by an auditory signal. The contrast was switched off and the display was evenly illuminated at the average luminance of the pattern. Observers were asked to hold a switch down as long as they could see a pattern. If the observer switch was not released, it meant that an afterimage of the pattern was seen. After 10 s of viewing the evenly illuminated display, the pattern was presented along with the auditory signal marking the beginning of a new trial, at a lower contrast. This procedure was repeated until the observer’s release of the switch corresponded with the switch-off of the pattern. At least 10 judgments were obtained for contrast values around this transitional zone; the data points represent the average. The dashed lines represent data from Ref. 8 (Fig. 10) for subjects DK and MC.
Percent contrast necessary to detect sinusoidal gratings in normal, unstabilized vision (solid lines), and during stabilization of the retinal image (dotted lines). In panel (a) the temporal waveform of target contrast was Gaussian with a 7.5 s increase and 7.5 s decrease. Method of staircase was used for obtaining threshold measures. The observer judged the presence or absence of the pattern during each target presentation. An unstabilized fixation point was supplied for both viewing conditions. The observers were instructed to attempt to maintain fixation under unstabilized viewing conditions. In panel (b) the method of adjustment was used wherein the observer adjusted the contrast to a level that he felt would not change. Although unstabilized fixation was supplied as before, no instructions were given for maintaining fixation under unstabilized conditions.
Contrast sensitivity measures and accuracy of image stabilization systems

November 1980

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10 Reads

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11 Citations

Journal of the Optical Society of America

Recently, it has been argued that the precision of image stabilization is reflected in the magnitude of the differences in contrast sensitivity measures obtained with and without image stabilization. Here we present two sets of data, one showing large and the other small differences in contrast sensitivity to sinusoidal gratings viewed under stabilized and unstabilized, normal conditions. Both sets of data were obtained by the use of the same apparatus optimized for image stabilization. Large differences occur between unstabilized and stabilized measures of sensitivity only when the observer is allowed to scan the unstabilized test grating, or to prolong inspection of the stabilized target thus allowing for disappearance of the stabilized image. On the other hand, when the target is presented for a few seconds and the observer fixates on it, normal image motion, which results from eye movements of fixation, is found to enhance contrast sensitivity by only a small amount. It would appear, therefore, that the extent of reduction of sensitivity for a stabilized grating cannot be used as an index of the precision of image stabilization.


(a) Optical configuration for presentation of stabilized images. (b) Viewing field containing the edge and test stimulus.
Stimulus threshold versus distance from an edge having a 1:20 luminance ratio. The background edge is continuously presented. The stimulus consists of a line 1′ wide by 30′ long; it was presented for 100 ms once each second. Results for both stabilized (dots) and unstabilized (crosses) viewing are given. (a) Subject BJB, (b) subject FXL. The smooth curves drawn through the data points are fitted by eye.
Stimulus threshold versus distance from an edge for the same condition as Fig. 2 but with the stimulus presented for 10 ms. (a) Subject BJB, (b) subject FXL.
Stimulus threshold versus distance from an edge for the same conditions as given in Fig. 2 except that both the background edge and test stimulus are presented together for 50 ms. (a) Subject BJB, (b) subject FXL.
Approximate representation of the brightness distribution across the sharp edge for a luminance ratio of 1:20 for unstabilized viewing.
Thresholds at luminance edges under stabilized viewing conditions

April 1980

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6 Reads

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14 Citations

Journal of the Optical Society of America

Increment thresholds were measured for a small, briefly presented test line as a function of distance from a high-contrast abrupt luminance edge. The experiments were carried out under both stabilized and unstabilized viewing conditions to determine the role of eye movements in the “edge threshold effect.” It was found that the edge threshold effect (i.e., the rise in threshold at the luminance edge) was less pronounced under stabilized conditions. We conclude from this that a significant portion of this effect is mediated by the temporal transients that are brought about by eye movements. Little difference is found between stabilized and unstabilized conditions when the background is briefly presented. Narrow bright bands appear on the bright side of a sharp edge for unstabilized viewing, but disappear under stabilization.


Effects of stimulus onset and image motion on contrast sensitivity

February 1979

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7 Reads

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12 Citations

Vision Research

Spatial sinusoidal gratings were viewed under both stabilized and unstabilized viewing conditions. They were presented either with a gradual or a sharp onset. The results indicate that contrast sensitivity to a range of frequencies centered around 2–3 deg is decreased by a maximum of 0.3 log units when high frequency temporal stimulation induced either by the sharp onset of the spatial pattern or by the motion of the retinal image is minimized. Data are presented which suggest that under conditions of minimal temporal stimulation, if fading of the stabilized image is also allowed, sensitivity may be decreased by a larger amount.


Citations (5)


... Since the early work by Ditchburn and Ginsborg (1952), Riggs et al. (1953), and Yarbus (1967), in which image fading with stabilization was demonstrated, the effects of FEM on spatial (Gilbert & Fender, 1969;Kelly, 1979a;Tulunay-Keesey & Bennis, 1979;Tulunay-Keesey & Jones, 1976;Watanabe, Mori, Nagata, & Hiwatashi, 1968) and spatiotemporal contrast sensitivity (Kelly, 1977;Kelly, 1979b;Kelly, 1981b), chromatic contrast sensitivity (Kelly, 1981a), detection of colored light (Ditchburn & Foley-Fisher, 1979), Vernier acuity (Tulunay-Keesey, 1960), edge, line, or overall form detection (Gerrits & Vendrik, 1970b;Gerrits & Vendrik, 1974; Tulunay-Keesey, 1960a), orientation discrimination (Rucci et al., 2007;Tulunay-Keesey, 1960), and retinal eccentricity (Gerrits, 1978) have been documented. Interestingly, there were large differences across studies in how much FEM affect perception. ...

Reference:

Suboptimal eye movements for seeing fine details
Effects of stimulus onset and image motion on contrast sensitivity
  • Citing Article
  • February 1979

Vision Research

... Our eyes move continuously even during fixation (for reviews, see: Rolfs, 2009;Rucci & Poletti, 2015). Microsaccades (MS) are one such fixational eye movement: They are small (<1 degrees of visual angle [dva]), often occur involuntarily, and are typically conjugate (Møller, Laursen, Tygesen, & Sjølie, 2002;Martinez-Conde, Macknik, & Hubel, 2004;Collewijn & Kowler, 2008;Rucci & Poletti, 2015), prevent perceptual fading (Tulunay-Keesey, 1982;Martinez-Conde, 2006;McCamy et al., 2012), and are informative oculomotor correlates to perception (Laubrock, Engbert, & Kliegl, 2008;Dankner, Shalev, Carrasco, & Yuval-Greenberg, 2017;Fried et al., 2014;Rucci & Poletti, 2015). ...

Fading of stabilized retinal images

Journal of the Optical Society of America

... For instance, although similar contrast sensitivity functions were obtained under normal viewing conditions, the contrast threshold elevation under stabilization ranged from zero (no effect at all) up to .10 times (1.0 log unit) across studies (Gilbert & Fender, 1969;Kelly, 1979a;Tulunay-Keesey & Bennis, 1979;Tulunay-Keesey & Jones, 1976;Watanabe et al., 1968). The differences in precision of retinal image stabilization (Gerrits, 1978) as well as the stimulus duration (Tulunay-Keesey & Jones, 1976;Tulunay-Keesey & Jones, 1980) have been identified as the primary determinants of these differences, and more precise stabilization and longer stimulus duration are associated with larger threshold elevation. ...

Contrast sensitivity measures and accuracy of image stabilization systems

Journal of the Optical Society of America

... ? Yes R: 4 2/1 R : 4 Nagy and Kamholz (1995) [ 50 Nicholas et al. (1996) [57] R: 3 3/1 2-3M 79% 0.0375 0.0375 Yes R: 6 2/1 R : 6 Olson et al. (1994) [58] ? 71% 0.2 a 0.1 a Yes T: 48 Polat and Sagi (1994) [60] T: 40 Rovamo et al. (1995 [66,67] ]3M 84% 0.1 0.1 Yes R: 8 Rovamo et al. (1996) [68] R: 8G 4/1 ]3G 84% 2 dB 1 dB No R: 10 2/1 R : 6 Sankeralli and Mullen (1996) [69] ? ...

Adaptation with a stabilized retinal image: Effect of luminance and contrast
  • Citing Article
  • December 1994

Vision Research

... Brightness gradually declines to low residual levels called the Eigengrau or subjective gray (Gibson & Waddell, 1952;Gur 1989;Knau & Spillman, 1997). The characteristics of this fading have been extensively tested; it depends on the size of the field, background luminance and the amount of spatial information present (Olson, Tulunay-Keesey, & Saleh, 1993). Others have confirmed that spatial information, that is changes in luminance that give rise to contrast in an image, fades more quickly (Kelly, 1979) than brightness (Knau & Spillman, 1997). ...

Fading time of retinally-stabilized images as a function of background luminance and target width
  • Citing Article
  • November 1993

Vision Research