Optical measuring system and method for coaxiality of extra-long-hole part

The invention relates to an optical measuring system and method for coaxiality of an extra-long-hole part, belonging to the technical field of coaxiality measurement. The measuring system comprises an oriented rod (101), a self-centering comprehensive measuring head (102), a position sensitive detector (PSD) (103), the extra-long-hole part (104), a spectroscope (105), a four-dimensional collimation platform (106), a laser transmitter (107), a motion control card (108), a reflecting mirror (109), a computer (110), a data acquisition card (111) and the like. During measurement, a laser collimation centerline is determined firstly according to the centers of a head hole and a tail hole and then the coaxiality value of the holes is obtained through a minimum zone method. The optical measuringsystem and method for the coaxiality of the extra-long-hole part has the advantages of high efficiency and high accuracy.