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Medical Forum / General / Vision / December 2006Question regarding the Contrast Sensitivity Function
Hi, My question is about a plot of the Contrast Sensitivity Function I found on http://www.webvision.med.utah.edu/imageswv/KallSpat24.jpg. I read the corresponding article on http://www.webvision.med.utah.edu/KallSpatial.html over and over again but I think I still miss something: Can someone please explain to me what the unit "Modulation threshold" on the y-axis of the plot means? Thanks a lot for yout input! Tim Allen > but I think I still miss something: Can someone please explain to me > what the unit "Modulation threshold" on the y-axis of the plot means? Modulation is the variance in contrast (amplitude) and threshold is the limit of sensory detection. So it's a measure of contrast sensitivity, plotted as the inverse. -MT > Modulation is the variance in contrast (amplitude) and threshold is the > limit of sensory detection. So it's a measure of contrast sensitivity, > plotted as the inverse. So this gives the measure for the minimum discernible difference in gray scale level that the eye can detect. Is this right? Tim Allen > > Modulation is the variance in contrast (amplitude) and threshold is the > > limit of sensory detection. So it's a measure of contrast sensitivity, > > plotted as the inverse. > > So this gives the measure for the minimum discernible difference in > gray scale level that the eye can detect. Is this right? So the y-axis values are the reciprocals of the minimum contrast modulation that is still visible at a given frequency. I found another article that states that if the CSF value is 200 at 10 cycles per degree, it means you can detect a 0,5% contrast signal. - As my math is bad, how do I calculate the 0,5% from 200? Tim Allen > degree, it means you can detect a 0,5% contrast signal. - As my math is > bad, how do I calculate the 0,5% from 200? My guess would be 1/200 = 0.5% -MT |
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