Abstract
A two-directional simultaneous measurement system of a surface deformation is proposed by using a speckle pattern. The speckle pattern is generated in the diffusely reflected light, when a rough surface is illuminated by a laser. Measurement methods using the speckle are divided into the two groups that are a speckle correlation method and a speckle interferometry method. The resolutions of the displacements of the speckle correlation and interferometry methods are about several to several 10 μm and less than 1 μm, respectively. The speckle correlation method is obtained in-plane components of displacement. The speckle interferometry method is obtained the component of the displacement in the direction of a laser radiation. So, in order to obtain in-plane components, the laser light is separated two beams that are illuminated to the two-direction (a vertical and horizontal directions) by using high-speed-switching-based methods. In this study, a measurement system is constructed by using the speckle interferometry method for the purpose of performing the two-directional simultaneous measurement. It consists of a He-Ne laser, Ar^+ laser, and optical parts. These lasers separately illuminate to the vertical and horizontal directions at the same time. The wavelengths of these lasers are selected by using optical filters, and in-plane components are simultaneously obtained.
