Imaging Method of Taper Thread for MeasurementCHANG Zhong-wei, ZHANG Rui-jie, HE Fu-yun 1. Daqing Petrochemical Plant Water and Vapour Division, Daqing 163714, China; 2. Daqing Petroleum Institute, Daqing 163318, ChinaAbstract:The projecting imaging method of tapered thread was studied through experiment and corresponding theoretical analysis was carried out to obtain clear thread images suitable for observation and measurement. A thread is put in a parallel optical field to obtain a projecting image, and the image is input computer by a CCD camera for further dimension measurement. The screw line will block the projection of thread teeth to some extent, but the disadvantage may be removed by rotating thread axis, and the introduced projecting error is little enough to be neglected.[著者文摘]