The Laplacian pyramid can be used to improve the overall illumination of photos, typically useful when part of the scene is in shadow. It can also smooth or enhance details in a photo without smoothing edges or introduce halos. Similar filters are used for tonemapping HDR pictures. Unfortunately the processing can take long time on big photos, so have patience... The filter was inspired by the paper "Local Laplacian Filters: Edge-aware Image Processing with a Laplacian Pyramid" by Sylvain Par