Digital shape compactness measure by means of perimeter ratios

A goodness compactness measure is necessary in computer medical diagnosis, shape analysis and computer vision processes. A compactness measure called the normalised E-factor (NEF) is introduced. It is shown that this measure is simple and robust to translations, rotations and scale changes and that it satisfies the set of criteria for a good compactness measure. Through a series of experiments it is shown that the normalised E-factor is useful for shape description, measuring digital compactness with or without holes and that it overcomes some drawbacks that are present in the classical and normalised discrete compactness measures.