Multigrid for Bundle Adjustment
This work addresses performance bottlenecks in computer vision pipelines for 3D reconstruction, offering a significant speedup for large-scale problems.
The paper tackled the superlinear scaling problem in bundle adjustment for large structure from motion pipelines by developing an unsmoothed aggregation multigrid preconditioner, resulting in solves up to 13 times faster than state-of-the-art methods on challenging datasets.
Bundle adjustment is an important global optimization step in many structure from motion pipelines. Performance is dependent on the speed of the linear solver used to compute steps towards the optimum. For large problems, the current state of the art scales superlinearly with the number of cameras in the problem. We investigate the conditioning of global bundle adjustment problems as the number of images increases in different regimes and fundamental consequences in terms of superlinear scaling of the current state of the art methods. We present an unsmoothed aggregation multigrid preconditioner that accurately represents the global modes that underlie poor scaling of existing methods and demonstrate solves of up to 13 times faster than the state of the art on large, challenging problem sets.