A methodological investigation of three psychophysical techniques for rapid measurement of contrast sensitivity

1983 ◽  
Author(s):  
Arthur P. Ginsburg ◽  
Alvah C. Bittner ◽  
Robert S. Kennedy ◽  
Mary M. Harbeson
Keyword(s):  
Contrast Sensitivity ◽  
Rapid Measurement

scholarly journals Curveball: A tool for rapid measurement of contrast sensitivity based on smooth eye movements

2018 ◽  
Vol 18 (12) ◽  
pp. 7 ◽  
Author(s):  
Scott W. J. Mooney ◽  
N. Jeremy Hill ◽  
Melis S. Tuzun ◽  
Nazia M. Alam ◽  
Jason B. Carmel ◽  
...  
Keyword(s):  
Eye Movements ◽  
Contrast Sensitivity ◽  
Rapid Measurement

A Methodological Investigation of Three Psychophysical Techniques for Rapid Measurement of Contrast Sensitivity

1983 ◽  
Vol 27 (3) ◽  
pp. 264-268 ◽  
Author(s):  
Arthur P. Ginsburg ◽  
Alvah C. Bittner ◽  
Robert S. Kennedy ◽  
Mary M. Harbeson
Keyword(s):  
Contrast Sensitivity ◽  
Visual Detection ◽  
Sine Wave ◽  
Video Display ◽  
Sensitivity Functions ◽  
Rapid Measurement ◽  
The Stability ◽  
Sine Wave Gratings ◽  
Method Of Adjustment ◽  
General Method

A general method for assessing visual capacity, contrast sensitivity function (CSF), has emerged in the last decade. The CSF describes visual detection of sine-wave gratings over a range of visual sizes. The purpose of this investigation was to compare the stability and sensitivity of three methods of obtaining rapid CSFs: Method of Adjustment (ADJ), Bekesy Tracking (B), and Method of Increasing Contrast (MIC). For each method, a microcomputer controlled video display was used to generate five different stationary gratings: 1, 2, 4, 8, and 16 cycles per degree (cpd). Individual contrast sensitivity functions were determined for each of 13 observers over five days. Analyses were conducted on reliabilities, means, and variances across frequencies, methods, and days. The MIC demonstrated near-largest or largest reliabilities over all frequencies across days. The MIC, in addition, appeared differentially stable from the onset of measurement (p > .10); while, both ADJ and B methods demonstrated differential instability (p < .002). The Methodof Increasing Contrast (MIC) may be recommended as the method of choice for assessing CSF based on the present findings.

Use of backscattered electron image intensity signals to calculate the water/cement ratio of concrete

1992 ◽  
Vol 50 (1) ◽  
pp. 356-357
Author(s):  
R. J. Lee ◽  
A. J. Schwoeble ◽  
Yuan Jie
Keyword(s):  
Reliable Data ◽  
X Ray ◽  
Rapid Measurement ◽  
Trained Personnel ◽  
Electron Image ◽  
Backscattered Electron ◽  
Production Period ◽  
Strength And Durability ◽  
Automated Procedures ◽  
Standard Density

Water/Cement (W/C) ratio is a very important parameter affecting the strength and durability of concrete. At the present time, there are no ASTM methods for determining W/C ratio of concrete structures after the production period. Existing techniques involving thin section standard density comparative associations using light optical microscopy and rely on visual comparisons using standards and require highly trained personnel to produce reliable data. This has led to the exploration of other methods utilizing automated procedures which can offer a precise and rapid measurement of W/C ratio. This paper discusses methods of determining W/C ratio using a scanning electron microscope (SEM) backscattered electron image (BEI) intensity signal and x-ray computer tomography.

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