This document discusses morphological image processing techniques. It defines morphological operations as non-linear operations related to the shape or morphology of features in an image. Specifically, it describes dilation, opening, and closing on binary images. Dilation expands shapes by adding pixels to boundaries, acting as a local maximum filter. Opening removes narrow connections between regions by first eroding and then dilating. Closing fills narrow holes by first dilating and then eroding. Both opening and closing use the same structuring element for the erosion and dilation.