The present work on laser speckle, speckle statistics, and speckle interferometry is to establish the usefulness and inherent limitation of the double exposure speckle interferometric method in three dimensional strain analysis.
In the first experiment using transparent cube and an annular disc specimens made of acrylic resin, compressive strain is given by using a microstrainer which is disigned specifically for giving small compression, and the magnitude of that strain is calculated by laser speckle interferometry.
Displacement vector distribution of an annular disc made of polyurethane resin which was compressed by the microstrainer is determined by pointwise filtering, and isothetic fringes are obtained by full-field filtering.
The sensitivity limit of laser speckle interferometry is examined theoretically and confirmed by experiment.
