I am currently using PIVlab to image horizontal flow in a viscous media (glucose syrup), and it's doing a great job. I saw that it was possible to extract "simple strain rate" from the velocity field. I would like to understand what is computed during the process and what is the physical significance of this parameter (any reference on the topic is welcome).
I am right now using PIV analysis as well. This is an awesome tool for capturing particle movement in granular system. I am wondering if there is any post process when plotting simple shear and strain rate contour? I tried to extract ASCII files and use the equations as you said and plot them but I cannot achieve the same result. Well, in my plot it doesn't look smooth or too much noise. If you did post process, would you mind to tell me what kind of method is that?
I am pretty sure that there is no postprocessing of the data. However, there is some postprocessing during image display: If your PIV images are e.g. 500x500 pixels, you might e.g. get 30x30 vectors after the analysis. Usually, the resulting map for any derivative would hence be 30x30 pixels too, but this is scaled up to 500x500 pixels (bilinear interpolation) to make the display look better.