Application of Digital Holography in Displacement Measurement

Charge-coupled device (CCD) and electrical addressable liquid crystal display (EALCD), as a kind of holography recording and reconstruction device, has taken their parts into holographic interferometry gradually. It adds new content and method to the development and application of holography. On the basis of theory analysis and practical experiment, a new method that combined double-exposure holographic interferometry with digital image processing, and combined CCD with EALCD is used in micro-displacement measurement. In my paper, I have studied the application condition of CCD/EALCD in digital holographic interferometry and have tried to do some digital image processing onto the hologram. Concerning off-axis holographic recording system, I have analyzed the fundamentals and conditions of CCD recording and the EALCD reconstruction. Simultaneously, I have also tried to process the holograms with digital image processing technique, and achieved better reconstruction results. Finally, I got the interference fringes successfully and calculated micro-displacement of object by the interference fringes.