Abstract
We have constructed a prototype of a Dynamic ESPI system which makes it possible to analyze dynamic feature of two-dimensional strain field completely. The system consists of two orthogonal sets of in-plane sensitive ESPI systems including two PZT actuators for phase modulation of two interfering optical branches. Spatio-temporal phase analysis is done by temporal Hilbert transformation algorithm which is applied to whole speckle data set acquired by a digital camera successively without any additional data. Attainable resolution of in-plane deformation is around 20 nm. Two normal and tangential strain components are calculated by numerical differentiation of two components of in-plane deformation. Resolution of the analyzed strain is estimates around 10^<-5>-10^<-6>. Temporal resolution of the system depends on data acquiring rate of a digital camera. In the present experiment, high speed camera was used and temporal resolution was 60 frames per second.
