Camera-aided autocollimation approach for increasing the effective measurement range of a photoelectric collimator

A camera aided autocollimation (CAAC) system is proposed to enhance the working range of a photoelectric collimator (PEC). This system consists of a camera surrounded by point light sources (LSs), a PEC, a rotary table, and a translation stage. As the tilt angle of the target varies, the intensity of the light from the LSs that is reflected by the target and received by the camera exhibits two symmetric peaks. The camera guides the target into the scope of the PEC by scanning these two peaks. This CAAC approach can automatically collimate a prism with an edge length of 10 mm and an initial tilt angle of 5° at a working range of 1.5 m. The error of the coarse collimation at 99.7% confidence is 602″.