scholarly journals A study of sine-wave contrast sensitivity by two psychophysical methods

1973 ◽  
Vol 14 (2) ◽  
pp. 313-318 ◽  
Author(s):  
D. H. Kelly ◽  
R. E. Savoie
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave

Contrast sensitivity for oscillating sine wave gratings during ocular fixation and pursuit

1988 ◽  
Vol 28 (7) ◽  
pp. 819-826 ◽  
Author(s):  
J.P. Flipse ◽  
G.J.v.d. Wildt ◽  
M. Rodenburg ◽  
C.J. Keemink ◽  
P.G.M. Knol
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave ◽  
Ocular Fixation ◽  
Sine Wave Gratings

Does L/M Cone Opponency Disappear in Human Periphery?

Perception ◽  
10.1068/p5374 ◽  
2005 ◽  
Vol 34 (8) ◽  
pp. 951-959 ◽  
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.

Contrast Sensitivity of Air-Breathing Nonprofessional Scuba Divers at a Depth of 40 Meters

1992 ◽  
Vol 75 (1) ◽  
pp. 275-283
Author(s):  
Nico A. M. Schellart
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Fresh Water ◽  
Test Pattern ◽  
Sine Wave ◽  
Air Breathing ◽  
Scuba Divers ◽  
Visual Contrast ◽  
Sine Wave Gratings ◽  
Visual Contrast Sensitivity

Photopic contrast sensitivity of air-breathing scuba divers was measured with a translucent test pattern at depths up to 40 m. The pattern was composed of sine wave gratings with spatial frequency and contrast changing logarithmically. The spatial transfer characteristics were measured at various depths under controlled optical conditions in seawater and in fresh water. Analysis indicates that the visual contrast sensitivity, and therefore probably also acuity, of sport divers is not affected up to depths of 40 m. This holds under ideal as well as poor diving conditions.

Peripheral contrast sensitivity for sine-wave gratings and single periods

1980 ◽  
Vol 20 (3) ◽  
pp. 243-252 ◽  
Author(s):  
J.N. Kroon ◽  
J.P. Rijsdijk ◽  
G.J. van der Wildt
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave ◽  
Sine Wave Gratings

Masking Effects Induced by Perceptual Colour Components

Perception ◽  
1997 ◽  
Vol 26 (1_suppl) ◽  
pp. 85-85
Author(s):  
L Bedat ◽  
A Saadane ◽  
D Barba
Keyword(s):  
Contrast Sensitivity ◽  
Image Coding ◽  
Sine Wave ◽  
Sensitivity Function ◽  
Contrast Sensitivity Function ◽  
Masking Effect ◽  
Perception Threshold ◽  
Colour Image ◽  
Spatial Frequencies ◽  
Achromatic Contrast

Signals from the three types of cone photoreceptors are generally thought to be combined into two opponent-colour components and an achromatic component. Here we have chosen the cardinal directions Ach (achromatic axis), Cr1 (reddish - greenish axis) and Cr2 (bluish - yellowish axis) defined by Krauskopf to build a colour image coding scheme based on features of the human visual system. In order to design the optimal perceptual quantisers, we studied the perception of colour at different spatial frequencies, measuring the effect of a colour masking signal on the perception threshold for achromatic or chromatic sine-wave gratings. Three cases were considered to describe these interactions. First, we measured the masking effect of each colour component by itself. For the two chromatic components, we observed a pedestal effect for low masking contrasts and threshold rises for higher masking contrasts. Second, we studied interactions between the two colour axes. With colour masking signals composed of Cr1 and Cr2 components, thresholds for Cr1 stimuli dropped at low contrasts of the Cr2 component of the masking signal. This effect disappeared for high Cr2 masking contrasts. This was true at all contrasts of the Cr1 component of the masking signal. Thresholds for Cr2 stimuli were not modified by Cr1 masking. Finally, interactions between the chromatic and achromatic components were more complex. We observed a strong modification of the achromatic contrast-sensitivity function when a Cr1 masking sine-wave grating was added. When the achromatic frequency was lower than the colour masking frequency, the threshold rose. However, when the achromatic frequency was higher than the colour masking frequency, there was a significant pedestal effect. The global effect is a shift of the achromatic contrast sensitivity function. With a Cr2 masking signal, no significant modification of the achromatic contrast-sensitivity function was observed.

scholarly journals Is the DeVries-Rose to Weber Transition Empirically Possible with Sine-Wave Gratings?

2005 ◽  
Vol 8 (2) ◽  
pp. 113-118
Author(s):  
Miguel A. García-Pérez
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Light Level ◽  
Sine Wave ◽  
Retinal Illuminance ◽  
Visual Functioning ◽  
Photopic Vision ◽  
Spatial Frequencies ◽  
Grating Acuity ◽  
Sine Wave Gratings

Visual functioning at various retinal illuminance levels is usually measured either by determining grating acuity as a function of light level or by determining how sensitivity to sine-wave gratings changes with retinal illuminance. The former line of research has shown that grating acuity follows a two-branch relationship with retinal illuminance, with the point of discontinuity occurring at the transition from scotopic to photopic vision. Results of the latter line of research have summarily been described as a transition from the DeVries-Rose law to Weber's law, according to which log sensitivity increases linearly with log illuminance with a slope of 0.5 over a range of low illuminances (the DeVries-Rose range) and then levels off and does not increase with further increases of illuminance (the Weber range). This paper aims at determining the compatibility of the results of these two lines of research. We consider empirical constraints from data bearing on the shape of the surface describing contrast sensitivity to sine-wave gratings as a function of spatial frequency and illuminance simultaneously, in order to determine whether they are consistent with a summary description in terms of DeVries-Rose and Weber's laws. Our analysis indicates that, with sine-wave gratings, the DeVries-Rose law can only hold empirically at low spatial frequencies.

scholarly journals Acute effect of alcohol intake on sine-wave Cartesian and polar contrast sensitivity functions

2014 ◽  
Vol 47 (4) ◽  
pp. 321-327 ◽  
Author(s):  
M.K. Cavalcanti-Galdino ◽  
J.A. da Silva ◽  
L.C. Mendes ◽  
N.A. dos Santos ◽  
M.L.B. Simas
Keyword(s):  
Contrast Sensitivity ◽  
Alcohol Intake ◽  
Acute Effect ◽  
Sine Wave ◽  
Sensitivity Functions

Contrast sensitivity in relapsing–remitting multiple sclerosis assessed by sine-wave gratings and angular frequency stimuli

2014 ◽  
Vol 31 (6) ◽  
pp. 381-386 ◽  
Author(s):  
JÁKINA G. VIEIRA-GUTEMBERG ◽  
LIANA C. MENDES-SANTOS ◽  
MELYSSA K. CAVALCANTI-GALDINO ◽  
NATANAEL A. SANTOS ◽  
MARIA LÚCIA DE BUSTAMANTE SIMAS
Keyword(s):  
Multiple Sclerosis ◽  
Visual System ◽  
Contrast Sensitivity ◽  
Sine Wave ◽  
Angular Frequency ◽  
Control Group ◽  
Spatial Frequencies ◽  
Relapsing Remitting ◽  
The One ◽  
Sine Wave Gratings

AbstractPrevious studies have shown that multiple sclerosis (MS) affects the visual system, mainly by reducing contrast sensitivity (CS), a function that can be assessed by measuring contrast sensitivity function (CSF). To this end, we measured both the CSF for sine-wave gratings and angular frequency stimuli with 20 participants aged between 21 and 44 years, of both genders, with normal or corrected to normal visual acuity. Of these 20 participants, there were 10 volunteers with clinically defined MS of the relapsing–remitting clinical form, with no history of optic neuritis (ON), as well as 10 healthy volunteers who served as the control group (CG). We used a forced-choice detection paradigm. The results showed reduced CS to both classes of stimuli. Differences were found for sine-wave gratings at spatial frequencies of 0.5, 1.25, and 2.5 cycles per degree (cpd) (P < 0.002) and for angular frequency stimuli of 4, 24, and 48 cycles/360° (P < 0.05). On the one hand, comparing the maxima of the respective CSFs, the CS to angular frequency stimuli (24 cycles/360°) was 1.61-fold higher than that of the CS to vertical sine-wave gratings (4.0 cpd) in the CG; for the MS group, these values were 1.55-fold higher. On the other hand, CS in the MS group attained only 75% for 24 cycles/360° and 78% for 4.0 cpd of the 100% CS estimates found for the CG at the peak frequencies. These findings suggest that MS affects the visual system, mostly at its maximum contrast sensitivities. Also, since angular frequencies and sine-wave gratings operate at distinct levels of contrast in the visual system, MS seems to affect CS at both high and low levels of contrast.

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