An Efficient Closed-Form Solution to Full Visual-Inertial State Initialization
This provides a more efficient and reliable startup solution for visual-inertial systems, though it appears incremental as it builds on existing approximations.
The paper tackles the problem of visual-inertial state initialization by proposing a closed-form method that avoids nonlinear optimization, achieving 10-20% lower initialization error, 4x shorter initialization windows, and 5x reduced computational cost compared to optimization-based approaches on the EuRoC dataset.
In this letter, we present a closed-form initialization method that recovers the full visual-inertial state without nonlinear optimization. Unlike previous approaches that rely on iterative solvers, our formulation yields analytical, easy-to-implement, and numerically stable solutions for reliable start-up. Our method builds on small-rotation and constant-velocity approximations, which keep the formulation compact while preserving the essential coupling between motion and inertial measurements. We further propose an observability-driven, two-stage initialization scheme that balances accuracy with initialization latency. Extensive experiments on the EuRoC dataset validate our assumptions: our method achieves 10-20% lower initialization error than optimization-based approaches, while using 4x shorter initialization windows and reducing computational cost by 5x.