Abstract: Aiming at the problem that the contact vibration measurement process needs to contact the structure under test and is susceptible to external influences, and the operation steps in the binocular vision noncontact vibration measurement process is more complicated, a noncontact image vibration based on Canny operator and FFT was proposed. Firstly, the moving image of the structure under test was acquired by the camera and grayscaled. The edge feature of the image was extracted by Canny operator. Then the pixel points of the image series were selected, and the motion information was extracted and traced by Matlab software. The edge pixel was obtained by FFT analysis. The vibration frequency of the point was the vibration frequency of the structure to be tested. Finally, the steadystate response experiment of the sinusoidal excitation of the simply supported beam and the impact response test of the cantilever beam were carried out, and the experimental measurement results were compared with the acceleration sensor measurement results. The results indicate that the relative error between the vibration frequency measured by the sinusoidal excitation of the 10 Hz to 35 Hz beam and the sensor measurement is less than 1.1%, and the relative error between the vibration frequency measured by the cantilever beam impact response and the sensor measurement is less than 0.7%, which has practical application feasibility.
Key words: noncontact measurement; vibration; Canny operator; fast Fourier transform（FFT）