[open] Pixelsize in Gabor patch generator
I am using the online Gabor patch generator and I was wondering how to determine the size of the stimulus.
I know that the Gabor patch for my project needs to have a radius of 2° and I also determined the pixels per degree for our setting but I am not sure whether I need to convert the radius into pixels or whether I should use the diameter then (so 4°)? Or does the size asked for in the generator refer to the whole square and not just the Gabor patch within it?
Also, I am trying to use different contrast levels. I am not too familiar with this and I was wondering whether, if I want to have a background with the mean luminance, I would start with the RGB values for both colours at 128 as the lowest possible contrast and then stepwise increase the difference (e.g. colour 1: 129 and colour 2: 127) or whether the lowest possible contrast would be 127 to 128 and then increase/decrease (e.g. next contrast would be at 126 and 129). I used the latter at first but I wasn't too sure about it (as it is only possible to use integers for the generator, but then the average wouldn't be an integer) but then if I use the first approach the background doesn't really seem to look right.
I would be really grateful, if someone could help me out with these questions!