  An electronic speckle shearing phase-shifting pattern interferometer (ESSPPI)
based on Michelson interferometer was based in this paper. A rotatable mirror
driven by a step motor in one of its reflective arm is used to generate an
adjustable shearing and the mirror driven by piezoelectric transducer (PZT) in
the other reflective arm was used to realize phaseshifting. In the experiments,
the deformation of an aluminum plate with the same extern-force on different
positions and different forces on the same position is measured. Meanwhile, the
phase distribution and phase-unwrap image of the aluminum plate with the
extern-force on its center position is obtained by the four-step phase-shifting
method.
