Date post: | 17-Jan-2018 |
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Zuzana Kukelova, Martin Bujnak, Tomas Pajdla
The Art of Solving Minimal Problems Tricks: Problem FormulationMicrosoft Research CambridgeCzech Technical University in PragueCapturing Reality s.r.o.
CapturingReality
How important is the problem formulation?
“The mere formulation of a problem is often far more essential than its solution, which may be merely a matter of mathematical or experimental skills. ….”
- Albert Einstein
Problem formulationThe formulation of the problem may significantly influence
• Complexity of the final “online” solver
• Sparsity of the elimination template
• Numerical stability
• Number of solutions
P4P+fAbsolute pose of a camera with unknown focal length
• Over-constrained system – 3.5 points sufficient• Different strategies for selecting equations
P4P+fDifferent formulations• Using distances
• Using ratios of distances
• Rotation matrix parametrized using quaternions
• DIAC – dual image of the absolute quadric
P4P+fPerformance of different solvers and different formulations
Problem formulationHow important is the problem formulation?
• Success = good formulation + good solver
• Finding a good solution one have to try many formulations & solvers
• Easy with automatic solver generators
P4P+fUsing an automatic generator we can quite quickly test and evaluate different, formulations, different orderings of variables or monomials
Polynomial system
Evaluation Solver source code