What impact have different types of border-handling on high pass or low pass filtering?
HPF or LPF linear operators. It means that an operation at pixel position i, j will only be affected by neighbors within the window size of your filter. Pixels outside the filter will not play a role - in other words, the effects of any filtering operation is localized around its support. Typically, if the image size post filtering is not a concern, we 0 pad an image and crop out the contents near the border with a size equal to half the filter window. To maintain the same size, it is advisable to replicate border values.