scholarly journals A single-channel model for spatio-temporal contrast sensitivity at low-to-medium spatial frequencies

2002 ◽  
Vol 2 (10) ◽  
pp. 6-6
Author(s):  
L. Kontsevich ◽  
C. W. Tyler
Keyword(s):  
Contrast Sensitivity ◽  
Channel Model ◽  
Single Channel ◽  
Temporal Contrast ◽  
Spatial Frequencies ◽  
Spatio Temporal

Flicker Contrast Sensitivity in Normal and Specifically Disabled Readers

Perception ◽  
1987 ◽  
Vol 16 (2) ◽  
pp. 215-221 ◽  
Author(s):  
Frances Martin ◽  
William Lovegrove
Keyword(s):  
Spatial Frequency ◽  
Contrast Sensitivity ◽  
Temporal Frequency ◽  
Temporal Contrast ◽  
Control Subjects ◽  
Visual Systems ◽  
Spatial Frequencies ◽  
Disabled Readers ◽  
Transient System

Temporal contrast sensitivity for counterphase flicker was determined for specifically disabled and normal readers to investigate whether the two groups differ in the functioning of their transient systems. In experiment 1, temporal contrast sensitivity was measured over a range of temporal frequencies with a spatial frequency of 2 cycles deg−1. Disabled readers were less sensitive than the control subjects at all temporal frequencies. In experiment 2, temporal contrast sensitivity was measured at a temporal frequency of 20 Hz over a range of spatial frequencies. Disabled readers were less sensitive than the controls at all spatial frequencies, with the differences between the groups increasing as spatial frequency increased. Both these findings are interpreted as supporting the hypothesis of a transient-system deficit in the visual systems of disabled readers.

scholarly journals Integration of spatio-temporal contrast sensitivity with a multi-slice channelized Hotelling observer

2013 ◽  
Author(s):  
Ali N. Avanaki ◽  
Kathryn S. Espig ◽  
Cedric Marchessoux ◽  
Elizabeth A. Krupinski ◽  
Predrag R. Bakic ◽  
...  
Keyword(s):  
Contrast Sensitivity ◽  
Temporal Contrast ◽  
Hotelling Observer ◽  
Spatio Temporal ◽  
Channelized Hotelling Observer

Red-green vs. blue-yellow spatio-temporal contrast sensitivity across the visual field

2011 ◽  
Vol 58 (19-20) ◽  
pp. 1736-1748 ◽  
Author(s):  
M.A. Díez-Ajenjo ◽  
P. Capilla ◽  
M.J. Luque
Keyword(s):  
Visual Field ◽  
Contrast Sensitivity ◽  
Temporal Contrast ◽  
Spatio Temporal

scholarly journals Psychophysical Evaluation of Achromatic and Chromatic Vision of Workers Chronically Exposed to Organic Solvents

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Eliza Maria da Costa Brito Lacerda ◽  
Monica Gomes Lima ◽  
Anderson Raiol Rodrigues ◽  
Cláudio Eduardo Correa Teixeira ◽  
Lauro José Barata de Lima ◽  
...  
Keyword(s):  
Visual Field ◽  
Contrast Sensitivity ◽  
Organic Solvents ◽  
Color Discrimination ◽  
Temporal Contrast ◽  
Spatial Frequencies ◽  
Exposed Workers ◽  
Occupationally Exposed ◽  
Snellen Chart ◽  
Psychophysical Evaluation

The purpose of this paper was to evaluate achromatic and chromatic vision of workers chronically exposed to organic solvents through psychophysical methods. Thirty-one gas station workers (31.5 ± 8.4 years old) were evaluated. Psychophysical tests were achromatic tests (Snellen chart, spatial and temporal contrast sensitivity, and visual perimetry) and chromatic tests (Ishihara's test, color discrimination ellipses, and Farnsworth-Munsell 100 hue test—FM100). Spatial contrast sensitivities of exposed workers were lower than the control at spatial frequencies of 20 and 30 cpd whilst the temporal contrast sensitivity was preserved. Visual field losses were found in 10–30 degrees of eccentricity in the solvent exposed workers. The exposed workers group had higher error values of FM100 and wider color discrimination ellipses area compared to the controls. Workers occupationally exposed to organic solvents had abnormal visual functions, mainly color vision losses and visual field constriction.

scholarly journals Effects of mean luminance on goldfish temporal contrast sensitivity

1998 ◽  
Vol 38 (1) ◽  
pp. 55-59 ◽  
Author(s):  
Joseph Bilotta ◽  
Francesca M. Lynd ◽  
Maureen K. Powers
Keyword(s):  
Contrast Sensitivity ◽  
Temporal Contrast ◽  
Mean Luminance

scholarly journals Aspheric Intraocular Lenses Implantation for Cataract Patients with Extreme Myopia

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Yanwen Fang ◽  
Yi Lu ◽  
Aizhu Miao ◽  
Yi Luo
Keyword(s):  
Contrast Sensitivity ◽  
Visual Quality ◽  
Intraocular Lenses ◽  
Wavefront Aberrations ◽  
Spatial Frequencies ◽  
Aspheric Iol ◽  
Significant Difference ◽  
Composite Scores ◽  
Cataract Patients

Objective. To evaluate the postoperative visual quality of cataract patients with extreme myopia after implantation of aspheric intraocular lenses (IOLs). Methods. Thirty-three eyes were enrolled in this prospectivestudy. Eighteen eyes with an axial length longer than 28 mm were included in the extreme myopia group, and the other 15 eyes were included in the nonextreme myopia group. Phacoemulsification and aspheric IOL implantation were performed. Six months after cataract surgery, best-corrected visual acuity (BCVA), contrast sensitivity, and wavefront aberrations were measured, and subjective visual quality was assessed. Results. The BCVA improved significantly after surgery for both groups, and patients in the nonextreme myopia group achieved better postoperative BCVA due to better retinal status of the eyes. The evaluation of contrast sensitivity without glare was the same in both groups, whereas patients in the nonextreme myopia group performed better at intermediate spatial frequencies under glare conditions. The two groups did not show a significant difference in high-order aberrations. With regard to subjective visual quality, the composite scores of both groups did not differ significantly. Conclusions. Aspheric IOLs provided good visual outcomes in cataract patients with extreme myopia. These patients should undergo careful evaluation to determine the maculopathy severity level before surgery.

Thermal Hydraulic Studies of a Fluoride Salt Cooled High Temperature Test Reactor With Different CFD Methods

2014 ◽  
Author(s):  
Chenglong Wang ◽  
Yao Xiao ◽  
Jianjun Zhou ◽  
Dalin Zhang ◽  
Suizheng Qiu ◽  
...  
Keyword(s):  
High Temperature ◽  
Channel Model ◽  
Single Channel ◽  
Fluoride Salt ◽  
Applied Physics ◽  
Local Flow ◽  
Single Channel Analysis ◽  
Test Reactor ◽  
Safety Operation ◽  
Temperature Test

The Fluoride-salt-cooled High temperature Reactor (FHR) is new reactor concept-about a decade old which is mainly on going in China and U.S. The preliminary thermal-hydraulic studies of the Fluoride salt cooled High temperature Test Reactor (FHTR) is necessary for the development of the FHR technology. In this paper, the thermal-hydraulics of FHTR (also called TMSR-SF) designed by Shanghai Instituted of Applied Physics (SINAP) is studied in different power modes. The temperature distributions of the coolant and the fuel pebble are obtained using a steady-state thermal-hydraulic analysis code for FHR. The comprehensive local flow and heat transfer are investigated by computational fluid dynamics (CFD) for the locations where may have the maximum pebble temperature based on the results from single channel analysis. The profiles of temperature, velocity, pressure and Nu of the coolant on the surface of the pebble as well as the temperature distribution of a fuel pebble are obtained and analyzed. Numerical results showed that the results of 3-D simulation are in reasonable agreement with that of single channel model and also illustrated safety operation of the preliminary designed TMSR-SF in different power mode.

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