bulia byak wrote:
The goal of the handle is not to turn noise into non-noise. Its main goal is to be visible. With inversion, it fails to be visible only when it overlays an object which is a copy of the handle, i.e. has inverse color relative to the surroundings and has the same shape. The probability of this is close to zero. Any other noise is not an obstacle to it being visible with inversion.
Actually, it's more likely to be invisible than a single colour if there are a lot of higher frequencies in the image (something that will be rare until we have patterns). Clearly it would be hard to see on a background of black and white angular regions.
Not that I know a better solution, perhaps pick one of three colours that is maximally distant from the underlying colours.
njh