From Basics to Adaptive and Viscous Morphology

After a brief refresher on regular morphological filters which use fixed structuring elements (S.E.), we take a look at grey-level adaptive filters, known as viscous filters [9]. Here the S.E. varies as a function of grey level. The next class of variable S.E.-based filter are the adaptive structural filters [1,2], in which the S.E. vary in size and shape as a function of image position, rather than grey level. We discuss what precautions are needed to make sure these filters conform to the definitions of morphological filters, as well as efficient algorithms.