|
To precisely measure two-dimensional inplane displacement, a new type laser speckle interferometer using a quad aperture palte was proposed.
By detecting two-dimensional movement of the lattice type interferogram the displacement of the target can be calculated.
Two-dimensional Fourier Transform was adopted to detect the movement of the interferogram in high speed.
The relation between the phase of the interferogram and the phase spectrum of its Two-dimensional Fourier Transform was revealed.
It was confirmed that this method can detect phase of the interferogram with an adequate accuracy from the optical signal including high frequency noises
|
