Investigation of drying paint by laser peckle image processing

In this work, a non contact optical method for the investigation of drying paint using dynamic laser speckle image processing is presented. Intensity of scattered light signals at the time of drying process of paint changes and corresponding correlation function also changes appropriately. Time history of speckle pattern of drying paint helps to assess the drying process. Speckle image photographs are taken with a regular interval of time and processed. Cross-correlation function between successive frames is plotted and the variation of the peak height shows a stationary maximum value at the time of surface becomes completely dry. This is a non contact, non-destructive low cost simple method to study the drying process of coatings.