Does the color difference on the two sides of the edge make a difference in the frequency measurement? e.g. will an edge where the two colors on either side are #ffffff and #fffffe have a different frequency than an edge where the two colors on either side are #ffffff and #000000?
@cma We oftentimes like to think of edges in images as borders between areas of different intensities/colors, which our visual system perceives as lines. We also think of high frequencies as corresponding to high rates of changes (just as a quickly oscillating wave changes value rapidly), and low frequencies the opposite. Going by these definitions, a drastic change in color (from #ffffff to #000000) will form a much stronger and better-defined edge than a minor change in color (from #ffffff to #fffffe, which is barely noticeable). The drastic change in intensity/color values will also correspond to our definition of a high frequency. On the other hand, a minor change in intensity/color corresponds to a low frequency and a less "strong" edge. In short yes, the color difference on both sides of an edge makes a difference, especially since the color/intensity differences are what we often consider to make up edges.