  We study efficiency of intensity-based dynamic speckle method for
characterization of dynamic events which occur at variable rate in time within
the temporal averaging interval. We checked ability of the method to describe
the speed evolution by i) numerical simulation at variable speed, ii)
processing of speckle patterns obtained from phase distributions fed to a SLM
at controllable change of the temporal correlation radius of speckle intensity
fluctuations and iii) conducting experiments with a polymer solution drying by
using a hot-stage. The numerical and SLM simulation experiments allowed for
modification of the used estimates in order to obtain relevant information
