基于Canny算子和FFT的非接触图像振动测量研究

Non-contact image vibration measurement based on Canny operator and FFT

针对接触式振动测量过程中需要接触被测结构且易受外界影响,双目视觉非接触式振动测量过程中操作步骤较复杂的问题,提出了一种基于Canny算子和FFT的非接触图像振动测量方法。首先通过相机采集被测结构的运动图像,并进行了灰度化处理,利用Canny算子提取了图像的边缘特征;然后选取了图像系列像素点,用Matlab软件跟踪提取了其运动信息,进行了FFT分析,得到了该边缘像素点的振动频率,即被测结构的振动频率;最后进行了简支梁正弦激励稳态响应实验与悬臂梁冲击响应测试实验,并将实验结果与加速度传感器测量结果进行了比较。研究结果表明:在10 Hz^35 Hz简支梁正弦激励下测得的振动频率与传感器测量结果相对误差小于1.1%,悬臂梁冲击响应测试下测得的振动频率与传感器测量结果相对误差小于0.7%,该方法具有实际应用的可行性。

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 noncontact 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.