Digital Speckle Correlation Technique And Its Application In Monitoring Structure

This paper described mainly a digital image processing technique in application of digital speckle measurement, including laser speckle and white light speckle method, in order to monitoring structure in service-bridge and pile foundation, etc. The main contents of this thesis are as follows: 1. Based on white light speckle method and digital speckle correlation method, this thesis investigated in detail the influences of image blurring and the change of image's position on white light digital speckle correlation method in the case of slant optical axis, and the formula of error theoretical were given. To eliminate the influences of image blurring and the change of image's position, the reference measurement was introduced and a new high resolution method of measuring in-plane displacement in the case of slant optical axis was described. The sensitivity and precision of this processing system were given. 2. A new automatic image calibrate technique based on digital speckle correlation and experiment process was expound. This method can measure accurately optical system's amplification coefficient under the automation control of computers. 3. A whole field testing technique base on pointwise analysis method of laser digital speckle has been presented. Speckle image was gathered by CCD and calculated by computer directly. Digital speckle array correlation method was used to improve its precision and practicability. 4. An open-ended system for digital speckle measurement has been implemented using c plus plus language and matlab language under windows operation system. This software supplied an open-ended platform for digital speckle study. We can get the speckle measurement program rapidly in the open-ended system.