Measuring deformation or variations in position or refractive index - using holographic-interferometric or Moire patterns for rapid evaluation

摘要

A holographic interferometric, or moire metric method of determining deformations or position variations of objects or refractive index variations in transparent bodies, fluids or gases uses at least two object images contg. frequency patterns for different object conditions sequentially imposed at a scanning plane. - The method enables the images to be quickly and practically evaluated and to be made visible. The local intensity modulations of the hologram image or moire pattern of two distinct object conditions are imposed on a radiation sensitive storage screen, pref. a t.v. screen. The patterns are scanned electronically and the corresp. overlayed output signals converted in an evaluation unit using time modulation.