Fast and Accurate Surface Normal Integration on Non-Rectangular Domains
This work addresses a classic but challenging problem in computer vision for applications like photometric stereo, offering a flexible and efficient solution, though it is incremental as it builds upon existing methods.
The paper tackled the problem of integrating surface normals for 3D shape computation by developing a solver that combines a Poisson integration model with an iterative Krylov subspace solver, preconditioning, and a fast marching initializer, achieving high accuracy, robustness, and computational efficiency on non-rectangular domains and real-world datasets.
The integration of surface normals for the purpose of computing the shape of a surface in 3D space is a classic problem in computer vision. However, even nowadays it is still a challenging task to devise a method that combines the flexibility to work on non-trivial computational domains with high accuracy, robustness and computational efficiency. By uniting a classic approach for surface normal integration with modern computational techniques we construct a solver that fulfils these requirements. Building upon the Poisson integration model we propose to use an iterative Krylov subspace solver as a core step in tackling the task. While such a method can be very efficient, it may only show its full potential when combined with a suitable numerical preconditioning and a problem-specific initialisation. We perform a thorough numerical study in order to identify an appropriate preconditioner for our purpose. To address the issue of a suitable initialisation we propose to compute this initial state via a recently developed fast marching integrator. Detailed numerical experiments illuminate the benefits of this novel combination. In addition, we show on real-world photometric stereo datasets that the developed numerical framework is flexible enough to tackle modern computer vision applications.