Spatial frequency masking in human vision: binocular interactions

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.

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Orientation Specificity and Spatial Selectivity in Human Vision

Perception ◽

10.1068/p020053 ◽

1973 ◽

Vol 2 (1) ◽

pp. 53-60 ◽

Cited By ~ 73

Author(s):

J A Movshon ◽

C Blakemore

Keyword(s):

Spatial Frequency ◽

Human Visual System ◽

Human Vision ◽

Orientation Tuning ◽

High Contrast ◽

Vertical Grating ◽

Spatial Frequencies ◽

High Contrast Grating ◽

Orientation Specificity ◽

Adaptation Method

An adaptation method is used to determine the orientation specificity of channels sensitive to different spatial frequencies in the human visual system. Comparison between different frequencies is made possible by a data transformation in which orientational effects are expressed in terms of equivalent contrast (the contrast of a vertical grating producing the same adaptational effect as a high-contrast grating of a given orientation). It is shown that, despite great variances in the range of orientations affected by adaptation at different spatial frequencies (±10° to ±50°), the half-width at half-amplitude of the orientation channels does not vary systematically as a function of spatial frequency over the range tested (2·5 to 20 cycles deg−1). Two subjects were used and they showed significantly different orientation tuning across the range of spatial frequencies. The results are discussed with reference to previous determinations of orientation specificity, and to related psychophysical and neurophysiological phenomena.

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Spatio-Chromatic Information Content of Natural Scenes

Perception ◽

10.1068/v96l1009 ◽

1996 ◽

Vol 25 (1_suppl) ◽

pp. 162-162 ◽

Cited By ~ 1

Author(s):

T Troscianko ◽

C A Parraga ◽

G Brelstaff ◽

D Carr ◽

K Nelson

Keyword(s):

Spatial Frequency ◽

Human Vision ◽

Natural Scenes ◽

Data Set ◽

Frequency Space ◽

Sensitivity Functions ◽

Visual Encoding ◽

Spatial Frequencies ◽

Hyper Spectral ◽

Fourier Spectra

A common assumption in the study of the relationship between human vision and the visual environment is that human vision has developed in order to encode the incident information in an optimal manner. Such arguments have been used to support the 1/f dependence of scene content as a function of spatial frequency. In keeping with this assumption, we ask whether there are any important differences between the luminance and (r/g) chrominance Fourier spectra of natural scenes, the simple expectation being that the chrominance spectrum should be relatively richer in low spatial frequencies than the luminance spectrum, to correspond with the different shape of luminance and chrominance contrast sensitivity functions. We analysed a data set of 29 images of natural scenes (predominantly of vegetation at different distances) which were obtained with a hyper-spectral camera (measuring the scene through a set of 31 wavelength bands in the range 400 – 700 nm). The images were transformed to the three Smith — Pokorny cone fundamentals, and further transformed into ‘luminance’ (r+g) and ‘chrominance’ (r-g) images, with various assumptions being made about the relative weighting of the r and g components, and the form of the chrominance response. We then analysed the Fourier spectra of these images using logarithmic intervals in spatial frequency space. This allowed a determination of the total energy within each Fourier band for each of the luminance and chrominance representations. The results strongly indicate that, for the set of scenes studied here, there was no evidence of a predominance of low-spatial-frequency chrominance information. Two classes of explanation are possible: (a) that raw Fourier content may not be the main organising principle determining visual encoding of colour, and/or (b) that our scenes were atypical of what may have driven visual evolution. We present arguments in favour of both of these propositions.

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Does L/M Cone Opponency Disappear in Human Periphery?

Perception ◽

10.1068/p5374 ◽

2005 ◽

Vol 34 (8) ◽

pp. 951-959 ◽

Cited By ~ 30

Author(s):

Kathy T Mullen ◽

Masato Sakurai ◽

William Chu

Keyword(s):

Spatial Frequency ◽

Contrast Sensitivity ◽

Sine Wave ◽

Human Vision ◽

Peripheral Retina ◽

Contrast Detection ◽

Colour Contrast

We have assessed the optimal cone contrast sensitivity across eccentricity in human vision of the two cone-opponent mechanisms [L/M or red-green, and S/(L + M) or blue-yellow] and the luminance mechanism. We have used a novel stimulus, termed a ‘sinring’, that is a radially modulated sine-wave arc, Gaussian enveloped in both angular and radial directions. This stimulus overcomes the problem inherent in Gabor stimuli of confounding stimulus spatial frequency, size, and eccentricity and so allows contrast sensitivity to be tracked accurately into the periphery. Our results show that L/M cone opponency declines steeply across the human periphery and becomes behaviourally absent by 25–30 deg (in the nasal field). This result suggests that any L/M cone-opponent neurons found in primate peripheral retina beyond this limit are unlikely to be significant for colour contrast detection measured behaviourally.

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Spatial frequency channels in human vision as asymmetric (edge) mechanisms

Vision Research ◽

10.1016/0042-6989(74)90016-9 ◽

1974 ◽

Vol 14 (12) ◽

pp. 1409-1420 ◽

Cited By ~ 144

Author(s):

C.F. Stromeyer ◽

S. Klein

Keyword(s):

Spatial Frequency ◽

Human Vision

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Contrast constancy: deblurring in human vision by spatial frequency channels.

The Journal of Physiology ◽

10.1113/jphysiol.1975.sp011162 ◽

1975 ◽

Vol 252 (3) ◽

pp. 627-656 ◽

Cited By ~ 335

Author(s):

M A Georgeson ◽

G D Sullivan

Keyword(s):

Spatial Frequency ◽

Human Vision

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Cortical Anatomy, Size Invariance, and Spatial Frequency Analysis

Perception ◽

10.1068/p100455 ◽

1981 ◽

Vol 10 (4) ◽

pp. 455-468 ◽

Cited By ~ 17

Author(s):

Eric L Schwartz

Keyword(s):

Spatial Frequency ◽

Human Vision ◽

Second Step ◽

Optical Pattern Recognition ◽

Optical Pattern ◽

Logarithmic Mapping ◽

Size Invariance ◽

Primate Vision ◽

The Brain ◽

Spatial Frequency Analysis

In a recent application of an algorithm developed in computer and optical pattern recognition, Cavanagh has suggested that a composite of spatial frequency mapping and complex logarithmic mapping would provide a translationally, rotationally, and size-invariant mechanism for human vision. In this work, Cavanagh has not made explicit the fact that this transformation is composite, that is, that the first step (global Fourier analysis) is perceptually, anatomically, and physiologically inconsistent with primate vision, but that the second step (complex logarithmic mapping) is actually embodied in the anatomy of the primate retinostriate projection. Moreover, it is the complex logarithmic remapping step which is entirely responsible for the computational simplification of the symmetries of size and rotation invariance. These facts, which have been extensively discussed in a recent series of papers, are briefly reviewed and illustrated. Furthermore, it is shown that the architecture of the retinostriate map may provide an example of computational anatomy in vision, such that the spatial representation of a stimulus in the brain may be of direct functional significance to perception, and to the nature of certain visual illusions.

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Edge Computation in Human Vision: Anisotropy in the Combining of Oriented Filters

Perception ◽

10.1068/p240603 ◽

1995 ◽

Vol 24 (6) ◽

pp. 603-622 ◽

Cited By ~ 10

Author(s):

Tim S Meese ◽

Tom C A Freeman

Keyword(s):

Spatial Structure ◽

Spatial Frequency ◽

Human Vision ◽

Contrast Effects ◽

Compound Structure ◽

Component Structure ◽

Zero Crossings ◽

Coding Scheme ◽

Two Component ◽

Sinusoidal Gratings

Above threshold, two superimposed sinusoidal gratings of the same spatial frequency (eg 1 cycle deg−1) and equal contrasts, and with orientations balanced around vertical, usually look like a compound structure containing vertical and horizontal edges. However, at large plaid angles (ie large differences between component orientations) and low plaid contrasts there is a tendency for the stimulus to appear as two overlapping gratings (component structure) with obliquely oriented edges. These dependencies of perceived spatial structure in plaids are incompatible with an edge-coding scheme that uses only circular filters to compute zero-crossings, but instead support the idea that different oriented filters can (compound percept) or cannot (component percept) be combined before edges are represented. Here, further evidence is presented in support of this hypothesis. Two-component plaid stimuli had plaid angles of 45° or 90°, and a range of plaid orientations (ie a range of orientations around which the plaid components were balanced). Observers indicated whether each stimulus was perceived as a compound or component structure for a range of plaid contrasts. In addition to angle and contrast effects, perceived spatial structure was also found to depend on plaid orientation: compound structures were perceived more often when the plaid components were balanced around the cardinal axes of the retina. It is suggested that the principles governing the combination of oriented-filter outputs might be learnt during the development of the visual system by using a Hebb-type rule: coactivated filters are more likely to combine their outputs when activated on future occasions. Given the prominence of vertical and horizontal orientations in a carpentered environment, this simple rule promotes a network that combines filters balanced around cardinal axes more readily than oblique axes, in agreement with the results.

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