Abstract: An apparatus for measuring rectilinear motion and rotation angle errors of a rectilinearly moving body having a horizontal, parallel two-surface mirror positioned in a horizontal plane and including two reflection mirrors whose reflection surfaces face each other and are spaced by a distance (2)d and a vertical, parallel two-surface mirror positioned in a vertical plane and including two reflection mirrors whose reflection surfaces face each other and are spaced by a distance (2)d, and also has a light source for generating a laser beam, semi-transparent mirrors for splitting the laser beam into two laser beams, optical path changing reflection mirrors for changing a direction of each laser beam, and position sensors for detecting positions of the laser beam reflected from the horizontal, parallel two-surface mirror and the vertical, parallel two-surface mirror, respectively fixed to positions outside of the rectilinearly moving body.

Abstract: [Problem]

Abstract: A method of deformation measurement using speckle interferometry comprises the steps of forming a series of speckle images at specified time intervals by using an interferometer to superpose a laser beam reflected from the object whose deformation is to be measured and a laser beam not affected by the object, storing the speckle images in a memory as they are formed, using the difference between the speckle image stored before the deformation and a second speckle image stored in the course of the deformation to measure the deformation between the times that the two speckle images were recorded, repeating this process for successive pairs of speckle images up to the one recorded after completion of the deformation, and adding together the individual deformation measurements obtained.