Abstract: An apparatus and method for measuring the surface deformation or displacement in objects. In one embodiment the apparatus includes an interference pattern generator which projects an interference pattern onto a detector mounted to the surface which is to be measured. As the surface deforms, the detector moves and sweeps across the interference pattern. By noting the changes in the light intensity, the deformation or displacement in the surface at the detector may be determined. In another embodiment, both the detector and the interference pattern generator are located on the surface and as the surface deforms, the relative change in the surface at the detector and the relative deformation or displacement of the surface at the interference pattern generator may be determined. In another embodiment a plurality of detectors and interference pattern generators are positioned to map the deformation or displacement of the surface at many locations on the surface.