METHOD FOR GRASPING DISPLACEMENT MODE BY USING HOLOGRAPHIC INTERFEROMETRY

摘要

PURPOSE:To grasp the dynamic displacement, by extracting only a dynamic elastic displacement component by an image processing manipulation, from both an interference fringe pattern of a regenerated image and a rigid body displacement component by a pickup. CONSTITUTION:A disk 4 is elastically resonated and a supporting table 5 is rigidly vibrated. Under this state, an appropriate light emitting timing signal is given from a trigger device 7, and a hologram is formed by double exposure recording. The regenerated image of said hologram is coded into a binary value by the image processing manipulation. The data of the interference fringes having fringe degrees is converted into a displacment quantity and it is stored in a memory. Light signal A emitted from a pulse laser and acceleration pickup signals B1-B3 of the table 5 are recorded, the relative displacement at the time of the double exposure is computed, and the results are stored in the memory. The rigid body displacement mode is subtracted from the displacement pattern of the holographic interference fringes in the memory. Thus only the elastic resonation mode of the disk 4 can be extracted.