568results about How to "No electromagnetic interference" patented technology

The invention relates to a device and a method for measuring the rotating speed of a rotating shaft based on a variable density sine fringe. The device comprises the variable density sine fringe, a high-speed image collection module, a high-speed image transmission module, an imaging processing software module and a computer. The method comprises the following steps: adhering a sensor for the variable density sine fringe onto the surface of the periphery of a rotating shaft to be measured; carrying out continuous imaging and recording on the variable density fringe by the high-speed imaging collection module; transmitting an image of the fringe to the computer by the image transmission module; carrying out Fourier transform on fringe signals at the positions of the same row of pixels in each frame of image by the image processing software module and adopting a peak frequency correction method to accurately correct peak frequency so as to obtain accurate fringe density information, then obtaining a time domain curve with which a rotation angular speed of the rotating shaft at the position of the fringe is covered, and then calculating the rotating speed signal of the rotating shaft through the rotation angular speed and the sampling frequency of a camera. According to the device and the method, non-contact measurement for the rotating speed of the rotating shaft in a certain range of rotating speed can be realized, and the device is high in measuring speed and high in precision.