A digital image processing method for estimating the level of hydrophobicity of high voltage polymeric insulating materials

Image analysis of water drop patterns on a flat polymeric insulator surface has been performed in order to find a simple mathematical function that indicates the level of hydrophobicity of an insulator surface. The result, a simple function given the name of “scaled entropy”, seems to correlate well with hydrophobicity as defined by the STRI classification. Some of the various pitfalls in the measurement procedure are identified, together with possible solutions for avoiding them