Research On Biaxial Autocollimator Based On ZYNQ

As a high-precision non-contact measuring instrument,the biaxial autocollimator can be used to measure small angles,flatness,straightness and so on.Based on the Xilinx ZYNQ development platform,from the principle of self-collating,this paper designed and built a complete biaxial self-collimator measuring system,with self-calibration function,using for long-distance small angle measurement.The specific work of this paper is as follows:In order to improve the accuracy of autocollimator at a long distance,reduce the measuring error caused by air distu rbances and temperature changes,a real-time online calibrating method for measuring the reference was proposed.Designed the overall control scheme based on ZYNQ.Implemented image acquisition,image processing and human-computer interaction.The image acquisition part was to achieve real-time image acquisition;the image processing part was to process the collected data,getting the image center,and calculate the current angle deflection;human-computer part was to display real-time data and angle,and some buttons were set for user to select the appropriate function.Image preprocessing in the image processing part was implemented in PL,and the other parts were implemented in PS.Studied several sub-pixel localization algorithms such as centroid method,Gaussian fitting method and least squares circle fitting method,analyzed the position accuracy,speed,and stability,selected centroid method to get the center of the spot.Calibrated and measured by CCD-AI autocollimator,experiments showed that the measuring accuracy of the online reference correction was improved when the angle was measured at a long distance.