A physical model is used to describe one or more field-size phenomena and, in representing them, it generates other quantities, which are the final output of the system. Sometimes the required thorough measurement of such quantities can lead to lose the total perception of the phenomenon under investigation. Digital image processing can not and should not obviously replace the measurements, but it can be a useful tool for capturing the global behaviour of the model-system and consequently of reality. This process can be especially effective in cases where, for certain configurations or for simplifying the model to its essential characteristics, the aim is to seek a simple representation, although not completely corresponding to reality.