Hey guys,

I'm wanting to use the rank filter module in skimage, but I'm not sure about the usage of percentile(). My intuition of how a percentile filter should work is:

for each pixel: grab all the values in the structuring element centred at that pixel sort them find the requested percentile; interpolate if necessary replace pixel with that value

However, the function doesn't require one percentile but two, p0 and p1. The docstring says "Only levels between percentiles [p0, p1] are used", but I don't understand what this means. What if three different values fall between p0 and p1? What if no values fall between them?