Design of a detection system for multiple optical-axis parallelism in an electro-optical sighting telescope

In order to achieve accurate measurement of multiple optical-axis parallelism of an electro-optical sighting telescope, a detection system for multiple optical-axis parallelism was designed based on a large-calibre off-axis concave parabolic mirror. The whole system, including optical imaging system, controlling platform and image acquisition and processing system, was designed. Using discrete cosine transform coefficients as evaluation standard, high-precise auto-focusing was achieved. Using a large-calibre off-axis concave parabolic mirror, the demands of various kinds of electro-optical sighting telescopes measurement were meeted. The automatic measurement of optifcal-axis parallelism among light axis, far-infrared axis and near-infrared axis was achieved. The actual measurement was carried out for a certain electro-optical sighting telescope. When the deviation angle among multiple optical-axis was between 0.04mrad and 0.08mrad, the relative error was less than 13%, considered as the limit of system detection angle. The results showe that the detecting system decreases the error of human factor and is universal and high efficient. The accuracy of measurement also meet the requirements.