Real-time Measurement of Vibration Frequency of REPDS Based on Vision

Aiming at the vibration frequency measurement of REPDS (Reduced Pressure Drop Stick), a measurement method based on vision is proposed. Firstly, the parameters of ellipse features of top disk and top disk mark in each image of REPDS are extracted. Next, these parameters are used to measure the position and attitude of the corresponding space circle. Then, the normal vector of the REPDS at a current time is calculated by using the measured coordinates of the center of the space circle. And the attitude angle of the REPDS is calculated by the normal vector. Finally, the vibration frequency can be obtained by Fourier transform and spectrum analysis of the attitude angle sequence obtained from multiple image processing. It is proved that the method is feasible by using simulation image data. The measurement error is less than 3.3%. The method is optimized with global fixed threshold and image subsampling. Real-time measurement of vibration frequency based on the method is realized on RK3588 embedded platform, and the measurement frequency is greater than or equal to 1Hz.