Modeling of the contrast sensitivity saturation depended on the number of cycles of the test sine-wave gratings

2000 ◽  
Author(s):  
Olga I. Krasilnikova ◽  
Nikolay N. Krasilnikov ◽  
Yury E. Shelepin
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave ◽  
Number Of Cycles ◽  
Sine Wave Gratings

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

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

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.

Haptic Detection of Sine-Wave Gratings

Perception ◽  
10.1068/p5425 ◽  
2005 ◽  
Vol 34 (7) ◽  
pp. 869-885 ◽  
Author(s):  
Stefan Louw ◽  
Astrid M L Kappers ◽  
Jan J Koenderink
Keyword(s):  
Power Law ◽  
Haptic Perception ◽  
Sine Wave ◽  
Detection Thresholds ◽  
Scanning Velocity ◽  
Probability Summation ◽  
Fourfold Increase ◽  
Number Of Cycles ◽  
Sine Wave Gratings ◽  
Neural Summation

We studied human haptic perception of sine-wave gratings. In the first experiment we measured the dependence of amplitude detection thresholds on the number of cycles and on the wavelength of the gratings. In haptic perception of sine-wave gratings, the results are in agreement with neural summation. The rate at which detection thresholds decrease with increasing number of cycles is much higher than can be accounted for by probability summation alone. Further, neural summation mechanisms describe the detection thresholds accurately over the whole spatial range probed in the experiment, that is wavelengths from 14 mm up to 225 mm. Earlier, we found a power-law dependence of thresholds on the spatial width of Gaussian profiles (Louw et al, 2000 Experimental Brain Research132 369–374). The current results extend these findings; the power-law dependence holds not only for Gaussian profiles, but also for a broad range of sine-wave gratings with the number of cycles varying between 1 and 8. Haptic perception involves tactual scanning combined with an active, dynamic exploration of the environment. We measured characteristics of the velocity and force with which stimuli were scanned while performing a psychophysical task. One particularly surprising finding was that, without being instructed, participants maintained an almost constant scanning velocity during each 45-min session. A constant velocity in successive trials of the experiment might facilitate or even be necessary for discrimination. Further, a large systematic dependence of velocity on scanning length was found. An eightfold increase in scanning length resulted in about a fourfold increase in scanning velocity. A second experiment was conducted to study the influence of scanning velocity on psychophysical detection thresholds. This was done by systematically imposing specific scanning velocities to the participants while the thresholds were measured. The main result of the second experiment was that psychophysical detection thresholds are constant over a relatively broad range of scanning velocities.

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.

Linear and nonlinear W-cells in C-laminae of the cat's lateral geniculate nucleus

1982 ◽  
Vol 47 (5) ◽  
pp. 869-884 ◽  
Author(s):  
M. Sur ◽  
S. M. Sherman
Keyword(s):  
Receptive Field ◽  
Contrast Sensitivity ◽  
Temporal Summation ◽  
Temporal Frequency ◽  
Optic Chiasm ◽  
Sine Wave ◽  
X And Y Cells ◽  
Linear And Nonlinear ◽  
Sine Wave Gratings ◽  
Y Cells

1. We used standard, single-cell recording techniques to study the response properties of 34 W-cells in the C-laminae of the cat's lateral geniculate nucleus. By W-cell, we mean a poorly responsive geniculate neuron that receives slowly conducting retinal afferents; these are quite distinct from geniculate X- and Y-cells. Our measurements included response latency to optic chiasm stimulation, plots of the receptive-field center, time course of response, and responses to counterphased, sine-wave gratings. This last measurement also involved the determination of contrast sensitivity, which is defined as the inverse of the contrast needed to evoke a threshold response at a particular spatial and temporal frequency of the grating. Many of these responses were compared to those of geniculate X- and Y-cells recorded in the A-laminae. 2. Each of the W-cells responded with a latency of at least 2.0 ms to optic chiasm stimulation, and most (76%) exhibited a latency of at least 2.5 ms. However, only 26 of these W-cells responded to visual stimuli, and these responses were weak or "sluggish," as has been reported previously. Receptive fields of these W-cells tended to be large, compared to those of X- and Y-cells, and included 11 on-center, 13 off-center, and 2 on-off center fields. 3. W-cells exhibited either linear (12 cells) or nonlinear (14 cells) spatial and temporal summation, as determined from their responses to counterphased, sine-wave gratings. Linearity of spatial summation was determined by measuring contrast sensitivity as a function of the grating's spatial phase. The linear W-cells' responses were sinusoidally phase dependent, and the nonlinear W-cells' responses were independent of spatial phase. Linearity of temporal summation was determined by the presence or absence of harmonic distortion in the response relative to the grating's counterphase rate. Linear W-cells responded chiefly at the grating's fundamental temporal frequency, whereas much of the nonlinear W-cells' responses occurred at the second harmonic of the grating's temporal frequency. Thus, nonlinear W-cells exhibited many of the characteristics previously described for Y-cells. 4. Spatial and temporal contrast-sensitivity functions were determined for seven linear and eight nonlinear W-cells. Overall sensitivity values of the linear and nonlinear W-cells were comparable, but these groups differed in terms of the nature of the response component (linear or nonlinear) that was more sensitive. 5. The linear W-cells in our sample included both tonic (comparable to the "sluggish-transient" type of retinal ganglion cells) types, while all nonlinear W-cells were phasic. Otherwise, no difference between linear and nonlinear W-cells was seen for latency to optic chiasm stimulation, receptive-field size, overall contrast sensitivity, responsiveness to visual stimuli, overall spatial resolution, or temporal resolution. 6...

scholarly journals Contrast sensitivity function of sine-wave gratings in children with acute malnutrition.

2009 ◽  
Vol 2 (1) ◽  
pp. 11-15 ◽  
Author(s):  
Natanael Antonio dos Santos ◽  
Caroline Costa Gomes Alencar ◽  
Yuri Henrique Nunes Dias
Keyword(s):  
Contrast Sensitivity ◽  
Sine Wave ◽  
Sensitivity Function ◽  
Contrast Sensitivity Function ◽  
Acute Malnutrition ◽  
Sine Wave Gratings
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