TEMPORAL RESOLUTION IMPROVEMENT IN DYNAMIC SPECKLE ANALYSIS

Abstract 
Dynamic speckle imaging is effective approach for visualization of areas of faster or slower micro
changes on a 3D object surface by analysis of speckle patterns formed on this surface under laser 
illumination. A 2D distribution of a statistical parameter related to the measured speed of changes is 
built as a map of activity. The map entries strongly fluctuate from point to point even when the speed is 
constant in the observed area. The relevant information is buried in a signal-dependent noise, which 
depends on (1) activity, and (2) ratio between the time of acquisition of the speckle patterns in the 
sequence and the temporal correlation radius of the process. The time of acquisition gives the temporal 
resolution of the method. In order to improve this resolution, we studied acquisition at time interval 
between the patterns that is much shorter than the temporal correlation radius of intensity fluctuations 
caused by the underlying processes in the tested object. 
Keywords: dynamic speckle, temporal resolution, simulation, optimization