Is the contrast of the GratingStim defined according to the Michelson Contrast?
I have looked at a similar question in this forum here - but it doesn’t quite answer my question.
And the description of contrast I found in the docs do not mention it either:
A value that is simply multiplied by the color
Value should be: a float between -1 (negative) and 1 (unchanged).
Set the contrast of the stimulus, i.e. scales how far the stimulus deviates from the middle grey. You can also use the stimulus opacity to control contrast, but that cannot be negative.
This website however described it as:
the difference between the maximum and minimum luminance divided by the sum of the maximum and minimum luminances
which is basically the Michelson Contrast.
Is that correct?