Calibration of 3D reconstruction system for liver surface based on binocular structured light

Abstract

To address the difficulty of liver surface 3D reconstruction system based on structured light during operation, this paper proposes a high-precision calibration method for liver surface 3D reconstruction system. First, the binocular model and surgical field of view of the 3D reconstruction system of the liver during the operation are analyzed, and the positions of the binocular camera and the projector are determined. Then, the pose conversion between binocular cameras is analyzed, and its calibration is completed. A projector calibration method based on the three-frequency and four-step phase solution method is proposed, and the phase solution process is formulated based on the principle of three-frequency and four-step phase solution. To address the difficulty of solving the centroid of the calibration plate in the process of projector calibration, an elliptic centroid solving method based on linear interpolation of subpixel coordinates is proposed. Finally, according to the actual surgical requirements, the appropriate hardware is selected to build an experimental platform for the three-dimensional reconstruction system of the liver surface. On this basis, several groups of calibration experiments indicate that the average calibration error of the system is 0.078 mm, and the maximum calibration error is 0.099 mm. Therefore, the proposed calibration method of the 3D liver reconstruction system has high calibration accuracy and meets the actual needs of doctors during the operation process.