Quadruple tripatch-wise modular architecture-based real-time structure from motion

Structure from motion (SFM), a research hotspot in the intelligent transportation field (including autonomous driving, environmental perception and augmented reality (AR) for artificial intelligence terminals), can automatically recover ego-motion state estimations and 3D scene reconstructions from multiple images or video sequences. Most existing vision methods operate offline in indoor scenes, and their reconstruction accuracies greatly depend on the tracking lifetimes and accuracies of feature points. Reprojection matrix and redundant regression noise computations are exponential disasters for the calculation and reconstruction drift of large-scale scenes. This paper proposes a quadruple tripatch-wise modular architecture (QTMA) for autonomous vehicle stereo image sequences that decomposes rigid scenes into nonrigid motion-segmented pieces for reconstruction. An advanced energy function for salient image features is established by combining multiple feature types with weighted finite-element mesh. Closed quadruple annular matching and relocation are performed via multiresolution pyramid images. The proposed incremental integral-mapping calculation method and unique tree-like stacked storage containers prolong the tracking lifetimes of consecutive frames and ensure the spatiotemporal consistency and robustness of the homonymous image features in different subsequences. Experimental results verify the effectiveness of this architecture for different transportation scenes; the frame rate processing speed reaches 30 fps, the calculation accuracy regarding the path distance difference reaches 99.49%, and the estimation results regarding the maximum speeds of motion are closer to the ground truth. The translation error of the motion pose is 0.0136%, and the rotation error is 0.0035 [deg/m], which has more yaw stability than the existing state-of-the-art methods. Furthermore, in the reconstructed point cloud quality demonstration, the mean value of roughness is reduced by 40.127%, the mean value of density is improved by 27.701%, and the accuracy reaches 91.149% within a certain distance tolerance. This paper has significant theoretical research value and application potential for positioning, path tracking, and navigation in adaptive cruise control (ACC) and advanced driver assistance systems (ADAS).