Speckle time evolution characterization by the co-occurrence matrix analysis

We describe some aspects of the measurement of dynamic speckle activity. We propose the use of the co-occurrence matrix of the time history of the intensity of a speckle pattern. Then we suggest a measure of the activity based on the use of one of its second order moments. Some numerical simulations were performed for testing purposes. The method was applied to the study of the drying of paint and was compared with gravimetric measurements. Experimental results obtained are shown and a good correlation is obtained.