Two simple methods for overall determination of mobility in dynamic speckle patterns

In this work, we present two simple methods to quantify the mobility of dynamic speckle patterns. The first method is based on the averaged pixel intensity differences between subsequent frames, while the second simply counts the fraction of pixels whose intensity changes with time in more than a certain quantity related to background noise. We have analyzed the applicability of these methods to different specimens (inorganic and biological) and compared the results to check their validity.