SYSTEM AND METHOD FOR REAL TIME MONITORING OF VIBRATIONS AND LARGE DEFORMATION IN DIFFUSED MATERIALS USING SEQUENTIAL SUBTRACTION AND IMAGE ENHANCEMENT

摘要

A Digital Speckle Pattern Interferometric (DSPI) device for monitoring the vibrations and mode shape of vibrating surfaces is disclosed. The device comprises a beam divider for splitting a laser beam into two mutually coherent object wave and reference wave. The object wave illuminates diffused surface of object. A digital filter spatially filters and collimates the reference wave. A means for combining the object wave with the reference wave forms the speckle interferogram which is converted into a video signal. Another means monitors the vibration and its mode shapes in real time when intensity of light falling on the object is either low or high. Lastly, a means creates an image for interferogram by subtracting current image from reference image and continues the process by subtracting the resultant image from the previous image. The recorded interferogram is displayed at the rate of 30 images per second after histogram equalization.