uDEFINITION:
the minimum contrast ratio that can be detected.
lIndicates
the smallest difference between shades of gray that can be detected.
uDepends
on Spatial Frequency
lDEFINITION: how many pairs of white and black bars fit into 1
deg. of visual angle.
lLow
spatial frequency
ufew
bars/deg.
lHigh
spatial frequency
umany
bars/deg.