Position measurement method based on linear array CCD with inverting prism

Position measurement in 2D plane plays an important role in many fields such as production controlling, automatic aiming, multimedia, and so on. The application of planar array CCD in 2D position measurement is facile. But it is difficult if both cost and precision to be taken into account. This paper proposed a method realizing 2D position measurement using linear array CCD to solve this problem. A special optical system is designed, including a main lens, an inverting prism, and a combination of a spherical lens and a cylindrical lens, by which the spots equidistant from the basic shaft(eg. x shaft) can be imaged into the same line. With a linear array CCD normal to the axis of the cylinder, the distance from the line to the basic shaft is measured, through which one value of the coordinate(eg. y) can be computed according to the object-to-image conjugate relationship. An inverting prism, eg. DOVE prism, rotating at a palstance of followed by the image at 2 omega,makes it possible to measure each value of 2D coordinate when the DOVE is in the initial point or turns to 45 degrees (image turns to 90). A possible application is also given.