Towards 3D Reconstruction With Variable-Baseline Binocular Endoscope for Minimally Invasive Surgery

Binocular endoscopy is widely used in minimally invasive surgery due to the easy acquisition of three-dimensional (3D) information. However, there are still limitations such as reduced precision in specific depth scenarios. To address the deficiency, we introduce a novel binocular endoscope reconstruction method with a variable baseline, which is founded upon the utilization of a multi-arm concentric-tube robot. First, the poses of two endoscopes with variable baselines can be obtained by modified ORB-SLAM3 algorithm. Then, the 3D structure can be reconstructed using the improved semi-global matching (SGM) algorithm based on two endoscopic images with known relative poses. Finally, to quantitatively calculate the reconstruction error, the experiment employs a method of co-reconstruction with a chessboard to indirectly measure the error. The result shows that the proposed method can effectively improve the accuracy of 3D reconstruction while maintaining real-time performance.