Sichuan Machinery Research and Design Institute

Abstract The traditional multi-line laser 3D reconstruction system relies on marker points to obtain complete 3D information of objects. However, in practical applications, many scenarios do not allow marker points to be pasted on objects. To solve this problem, we adopt a binocular tracking-based method to achieve marker-free stitching of multi-line laser reconstructed 3D data. The calibration of the binocular tracking system and the joint calibration between the multi-line laser system and the tracking ball cage constitute the core challenges of the system. To quickly and accurately complete the calibration of the entire system, this paper proposes a bundle adjustment optimization method based on a cross pole. This method utilizes multiple encoded marker points on the cross pole and their real 3D data. By capturing the cross pole images at different positions through the binocular tracking system, the internal and external parameters of the binocular tracking system are calibrated using the bundle adjustment optimization method in combination with the 3D data of the cross pole and the recognized image points. During the joint calibration of the multi-line laser system and the tracking ball cage, we simultaneously use the binocular tracking system and the multi-line laser system to capture cross pole images. By capturing cross pole at different positions, we can obtain the positional relationship between the cross pole, the binocular tracking system, and the multi-line laser system. Based on these positional relationships, we adopt a multi-position attitude optimization algorithm to calibrate the transformation relationship between the multi-line laser system and the tracking ball cage, thus completing the calibration of the entire system. Finally, based on all the calibration results, we can achieve 3D reconstruction of objects. Compared with the traditional method based on a planar calibration board, the calibration method proposed in this paper only requires one cross pole to complete the calibration of the two key steps, which not only improves the calibration accuracy but also simplifies the calibration process.