Combined Effects of Spatial Frequency and Retinal Eccentricity upon Fixation Disparity

1986 ◽  
Vol 63 (8) ◽  
pp. 619-626 ◽  
Author(s):  
CLIFTON SCHOR ◽  
MICHAEL WESSON ◽  
KENNETH M. ROBERTSON
Keyword(s):  
Spatial Frequency ◽  
Retinal Eccentricity ◽  
Combined Effects ◽  
Fixation Disparity

The effects of the spatial frequency and size of stripes on the hue appearance of striped woven fabrics

2018 ◽  
Vol 89 (12) ◽  
pp. 2423-2432 ◽  
Author(s):  
Youngjoo Chae
Keyword(s):  
Statistical Analysis ◽  
Spatial Frequency ◽  
Prediction Model ◽  
Predictive Accuracy ◽  
Woven Fabrics ◽  
Color Appearance ◽  
Combined Effects ◽  
Spatial Properties ◽  
Spatial Frequencies

In this research, the effects of the spatial properties, that is, spatial frequency and size, of stripes on their color appearance in striped woven fabrics were investigated. The lightness, colorfulness, and hue of stripes in three types of 180 striped fabrics, in which stripes were arranged in different spatial frequencies and sizes with different adjacent colors, were visually estimated by observers. Through the statistical analysis of the visual estimates, it was found that the spatial properties of stripes affect their hue appearance, while their lightness and colorfulness appearances are not significantly affected. In general, when the stripes become thinner and increase in spatial frequency, their hues appear more different from their actual hues. These effects of spatial properties on hue appearance were found to become stronger with lighter and more chromatic adjacent colors. Finally, a prediction model of the combined effects of the spatial properties of stripes and the colorimetric properties of adjacent colors was derived, and its great predictive accuracy was proven through numerical and statistical evaluations. It is envisaged that not only will the findings of this research provide advantageous conditions to design striped woven fabrics with desired color appearances, but they will also be the foundation for modeling various color appearance effects that occur in bicolor or multicolor patterned fabrics.

scholarly journals Stereopsis, spatial frequency and retinal eccentricity

1995 ◽  
Vol 35 (16) ◽  
pp. 2329-2337 ◽  
Author(s):  
John Siderov ◽  
Ronald S. Harwerth
Keyword(s):  
Spatial Frequency ◽  
Retinal Eccentricity

scholarly journals Title: Suppression durations for facial expressions under breaking continuous flash suppression: effects of faces’ low-level image properties.

2020 ◽  
Author(s):  
Abigail Webb ◽  
Paul Hibbard
Keyword(s):  
Spatial Frequency ◽  
Facial Expressions ◽  
Combined Effects ◽  
Frequency Content ◽  
Limited Evidence ◽  
Continuous Flash Suppression ◽  
Low Level ◽  
Facial Stimuli ◽  
Suppression Effects

Perceptual biases for fearful facial expressions are observed across many studies. According to the low-level, visual-based account of these biases, fear expressions are advantaged in some way due to their image properties, such as low spatial frequency content. Breaking continuous flash suppression (b-CFS) has explored these effects, and demonstrated similar biases for detecting fearful facial expressions. However, there is a degree of empirical disagreement regarding the range of spatial frequency content. Recent findings from a b-CFS study highlight the role of high, rather than low spatial frequency content in determining faces’ visibility. The present study contributes to ongoing discussions regarding the efficacy of b-CFS, and shows that the visibility of facial expressions varies according to how faces are normalised for physical contrast and spatially filtered. Findings show limited evidence of a bias for detecting fearful facial expressions, but importantly, they show that such biases are less likely to occur when faces are normalised for apparent, perceived contrast, compared to physical contrast. Together these findings further the current understanding of the combined effects of spatial frequency and contrast on face visibility under b-CFS, and raise important questions regarding procedures used to standardise facial stimuli.

Spatial properties of envelope-responsive cells in area 17 and 18 neurons of the cat

1996 ◽  
Vol 75 (3) ◽  
pp. 1038-1050 ◽  
Author(s):  
Y. X. Zhou ◽  
C. L. Baker
Keyword(s):  
Receptive Field ◽  
Spatial Frequency ◽  
Direction Selectivity ◽  
Retinal Eccentricity ◽  
Area 17 ◽  
Resolution Limit ◽  
Spatial Properties ◽  
Processing Stream ◽  
Spatial Frequencies ◽  
Frequency Selective

1. Many neurons in areas 17 and 18 respond to spatial contrast envelope stimuli whose Fourier components fall outside the cell's spatial-frequency-selective range. The spatial properties of such envelope responses are investigated here and compared with responses to conventional luminance-defined gratings to explore the underlying receptive-field mechanism. 2. Three spatial properties of envelope responses are reported more extensively in this paper. First, the envelope responses were selective to the carrier spatial frequency in a narrow range of frequencies higher than a given cell's luminance spatial frequency selective range (luminance passband). Second, a given cell's dependence on envelope spatial frequency often differed from its luminance passband. Last, the optimal carrier spatial frequency did not shift systematically with the envelope spatial frequency, supporting the hypothesis that the carrier and envelope spatial-frequency dependencies were mediated by distinct mechanisms. 3. In contrast to the direction selectivity to the envelope motion in many envelope-responsive cells, no direction preference to carrier motion was found for envelope responses. The direction of carrier motion did not alter the direction selectivity for envelope motion, further supporting the hypothesis that the carrier and envelope temporal properties were mediated by separate mechanisms. 4. The distributions of the optimal carrier and luminance spatial frequencies among envelope-responsive cells were analyzed. The optimal carrier spatial frequencies were randomly distributed from five times the cell's optimal luminance spatial frequency to the upper resolution limit of the X-retinal ganglion cells at the same retinal eccentricity, suggesting that the selective ranges of envelope responses and luminance responses are not strongly correlated over the population of envelope-responsive cells. 5. Our data support a "two-stream" receptive-field model for envelope-responsive cells. One stream is a conventional, spatially linear receptive-field mechanism, mediating luminance responses for the cell; the other mediates envelope responses and consists of a two-stage processing: a set of spatially small and distributed nonlinear neural subunits whose outputs are spatially pooled at the second stage. 6. In conclusion, this study indicates that envelope responses in area 17 and 18 neurons cannot be due to a nonlinearity that is common to all visual stimuli before narrowband spatial-frequency-selective filtering; instead, a specialized processing stream, parallel to the conventional luminance response stream, is needed to supplement the traditional luminance processing stream in these cells. This specialized stream responds to the envelope stimuli and is selective to their carrier and envelope spatial frequencies. The distributions of the optimal luminance and carrier spatial frequencies indicate a rich variety of possible integration between luminance and envelope information.

Orientation Selectivity of the Human Visual System as a Function of Retinal Eccentricity and Visual Hemifield

Perception ◽  
1981 ◽  
Vol 10 (3) ◽  
pp. 273-282 ◽  
Author(s):  
Alan Beaton ◽  
Colin Blakemore
Keyword(s):  
Spatial Frequency ◽  
Visual System ◽  
Human Visual System ◽  
Orientation Selectivity ◽  
Orientation Tuning ◽  
Retinal Eccentricity ◽  
Contrast Threshold ◽  
Systematic Change ◽  
Visual Hemifield ◽  
High Contrast Grating

An adaptation method was used to determine the specificity of orientation-selective channels in the human visual system at different retinal eccentricities (up to 16 deg) in both hemifields of each eye. For a vertical test grating, the elevation in contrast threshold produced by adapting to a high-contrast grating of the same spatial frequency but variable orientation was equated with the contrast levels of a vertical adapting grating that produced equivalent effects ( equivalent-contrast transformation). This enabled comparisons to be made between the orientation tuning of the aftereffect at different retinal loci. For the spatial frequency employed (3 cycles deg−1), no systematic change in orientation selectivity was found as a function of either retinal eccentricity or the hemifield (and hence the cerebral hemisphere) stimulated.

Human pattern-evoked electroretinogram

1984 ◽  
Vol 51 (5) ◽  
pp. 939-951 ◽  
Author(s):  
R. F. Hess ◽  
C. L. Baker
Keyword(s):  
Spatial Frequency ◽  
Evoked Potential ◽  
Temporal Frequency ◽  
Peak Frequency ◽  
Retinal Eccentricity ◽  
Pattern Erg ◽  
Band Pass ◽  
Mean Luminance

We have recorded electroretinographic (ERG) responses to grating patterns whose spatial, temporal, and contrast parameters were varied. The resultant evoked potential is dependent on spatial frequency and it exhibits a spatial band-pass characteristic. The peak frequency is dependent on retinal eccentricity. These findings are independent of temporal frequency, contrast, or mean luminance in the photopic range. These results suggest that the pattern ERG originates from a postreceptoral site.

scholarly journals Vergence accuracy in an autostereoscopic display

2021 ◽  
Author(s):  
Luca Lo Verde ◽  
Anthony Matthew Norcia
Keyword(s):  
Retinal Eccentricity ◽  
Fixation Disparity ◽  
Autostereoscopic Display ◽  
Made In

When fixating an object, observers typically under or over-converge by a small amount, a phenomenon known as "fixation disparity". Fixation disparity is typically measured with physical fixation targets and dichotically presented nonius lines. Here we made fixation disparity measurements with an autostereoscopic display, varying the retinal eccentricity and disparity of the fixation targets. Measurements were made in a group of four practiced observers and in a group of thirteen experimentally naïve observers. Fixation disparities with a zero-disparity target were in the direction of fixation behind the plane of the screen and the magnitude of the fixation disparity grew with the eccentricity of the fixation targets (1-5 deg in the practiced observers and 1 – 10 deg in the naïve observers). Fixation disparity also increased with increasing disparity of the targets, especially when they were presented at crossed disparities. Fixation disparities were larger overall for naïve observers who additionally did not converge in front of the screen when vergence demand was created by crossed disparity fusion locks presented at 5 and 10 deg eccentricities.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

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