A new estimator for activity on dynamic speckles based on contrast of sucessive correlations

In this work, we propose the contrast of sucessive correlations as a valid estimator for activity on dynamic speckles. We call “sucessive correlations” the correlation coeficients between two sucessive instants recorded on a Time History Speckle Pattern (THSP). In following, by dividing the standard deviation of these coeficients by their mean value, we get the corresponding contrast of sucessive correlations. A wide number of THSPs was simulated, using a numerical model previous developed by one of the authors, and the new index was compared with the corresponding inertia moments of cooccurrence matrices. A comparison with real THSPs, obtained during a drying paint process, was done. We found a strong correlation between the contrast of sucessive correlations and the inertia moment, sugesting the validity of this new estimator.