An Efficient Closed-Form Solution to Full Visual-Inertial State Initialization

TL;DR

This paper introduces a fast, closed-form visual-inertial state initialization method that outperforms traditional iterative approaches in accuracy and efficiency, suitable for real-time applications.

Contribution

The authors develop an analytical, non-iterative initialization technique for visual-inertial systems, reducing computational cost and initialization time while maintaining high accuracy.

Findings

Achieves 10-20% lower initialization error than optimization-based methods.

Uses 4x shorter initialization windows.

Reduces computational cost by 5x.

Abstract

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.