Design of a New Coded Target With Large Coding Capacity for Close—Range Photogrammetry and Research on Recognition Algorithm

Large-scale industrial equipment monitoring requires a large number of measurement points. To achieve fully automated measurement using photogrammetry, a large number of coded targets are required. In order to improve the coding capacity and decoding accuracy of coded targets in large-scale industrial photogrammetry, this paper designs a new coded target for digital industrial photogrammetry, which combines the characteristics of the circular coded target and the dot-distribution coded target. The max coded capacity can be 1,048,576. Experiments were carried out from different shooting angles and different distances in simple and complex scenes and the results show that the coded target is easy to be extracted and identified, with large coding capacity and high positioning accuracy. The coded target can be used for point matching and image orientation in large-scale photogrammetry, or even can be used as measuring point so as to realize the automatic management of a large number of measuring points.