一、引言近年来在许多测量场合都增加了对非接触式传感器的需要,例如三坐标、具有中间测量仪器的机床及装配机器人等。对好几种系统,如声学、气动、电子及光学系统等作了考查,其中一些现已付诸使用,如单光束、双光 I. INTRODUCTION In recent years, the need for non-contact sensors has increased in many measurement occasions, such as three-coordinate, machine tools with intermediate measuring instruments and assembly robots. Several systems such as acoustic, pneumatic, electronic and optical systems have been examined, some of which are now in use, such as single beam, double beam