Abstract: Due to high accuracy of electronic theodolite, multi-theodolites based industrial measurement systems are widely used for geometric detection of large-scale industrial products. However, theodolites can’t direct and recognize targets automatically, it exists the defects of inefficiency, Low accuracy etc. Automatic targets directing and recognizing(ATD&R) will be a new direction for the next generation theodolites. A novel technology is presented here to settle for targets approximate positioning. A camera is mounted on the theodolite, then they are calibrated for the mutual coordinate systems parameter, before measurement, targets image captured, when the image coordinates of the targets are known by image characteristic recognizing technology, direction data of all the targets can be calculated. Theoretical derivation and experiments show that the presented method is effective to get the targets’ approximate position.

Key words: Electronic theodolite, Image processing, ⁺Resection, ⁺Geometric detection