Research on digital holographic interferometry based on EALCD in three dimensional deformation measurements of objects

Abstract

In recent years, with the occurrence of photoelectric sensitive devices such as charge-coupled device (CCD) and electrical addressed liquid crystal display (EALCD), particularly with the development in the computer technology, digital holography interferometry has been developing rapidly. Digital holography was one of the important techniques in the field of three-dimensional non-contact testing. In order to realize the digitalization and real-time of the holographic interferometry, the digital holographic interferometry system based on EALCD and CCD for displacement and three dimensional deformation measurement of objects is established. The hologram and reconstructed hologram are recorded by CCD. The hologram is reconstructed by EALCD instead of holographic plate. The interference fringes which caused by micro displacement and deformation has been realized by this system. The reconstruction images of objects and holographic interference fringes are all preferable. In this paper, the holographic reconstruction and interference fringe has been enhanced and denoised by compiling program based on MATLAB and C++ in digital image processing. The single algorithm cannot meet the requirement of the experiment, so various algorithms were used in combination in order to enhance image quality and make interpretation and calculation more convenient. The straight fringes reflect the micro displacement of the object, the bending fringes represent the deformation of the object. Based many advantages of CCD and EALCD, the actual holographic interferogram with high contrast can be obtained quickly in our experiments, which the precise measurement of micro displacement and three-dimensional deformation of objects can be acquired