Vibration Measurements Based On The Linear Ccd And The Movement Of Interference Fringes

Based on the movement of Interference fringes, a new non-contact vibrationmeasurement technique is proposed in this dissertation. The relationship betweendisplacement of Interference fringes and vibration amplitude is the basis of thetechnique. The Interference fringes could be captured by the Linear CCD and convertedinto the electrical signals. Vibration information could be reconstructed and could bedisplayed on the screen. An algorithm is proposed to get vibration amplitude. Thealgorithm is tested and verified with Matlab software. A software containing thealgorithm is designed with VC++6.0and is tested and verified by the experiment. Thenon-contact technique could be used to get vibration in long distance.The dissertation contains as follows:1. The relationship between movement of Interference fringes and phase differenceof two beams slit light is introduced in this dissertation at first. Two beams of slit lightdiffract and the two beams of diffraction interfere behind a focusing lens. The change ofphase difference of two slit lights causes the change of Interference fringes, whichexpressed as the Interference fringes move around. Actually, the relationship of fringesmovement and phase difference is periodic function and is proportional relationship inone period.2. The algorithm is tested and verified by Matlab software. The factors that couldpossibly affect the results of the experiment are tested so that a lot of experimental workcould be reduced.3. An software is designed by VC++6.0, which could be run in the Windowssystem. The software could communicate with the data acquisition card and could beused to set the parameter of the data acquisition card. The required information ofvibration could be displayed in the screen. The software is tested in the experiment.4. An experimental platform is set up and the sinusoidal vibration signal iscaptured, which show the correctness of the technique.The technique is different from the others. The linear CCD as the photoelectricdetector could show the Interference fringes accurately. In this way, intensity distribution of interference fringe could be captured. The vibration amplitude could beget from the movement of the Interference fringes by the algorithm. The technique alsocould reconstruct vibration speed and vibration frequency. The method also has manyadvantages, such as fast velocity, high precision, and so on.