Figure 1

Illustration of locally adaptive behaviour of BF. The b/w image (top) shows the original image (hot sphere plus warm background). The blue dots denote selected positions (labelled a-g) for which the 2D BF kernel is computed and shown as colour-coded image (small weights: blue, large weights: red) at the bottom. Note how the kernel adjusts itself to the selected target position, including only neighbouring pixels of similar intensity in the averaging procedure.