Enhancing monocular visual positioning: 3D target-assisted initialization

Monocular visual positioning systems are valued for their low cost and straightforward calibration. However, the lack of real-scale information and the complexity of initialization processes limit their application in scenarios requiring accurate absolute positioning. Existing solutions present trade-offs: markerless approaches depend on environmental priors (e.g., fixed camera height constraints) for scale recovery, while marker-based methods typically necessitate that target patterns remain within the camera’s field of view throughout the process. To address these challenges, we propose a 3D target-assisted initialization method that enables scale recovery with just two target images. This modular approach can be seamlessly integrated into monocular simultaneous localization and mapping (SLAM) frameworks. We validated our proposed initialization method through integration with ORB-SLAM3 and semi-direct visual odometry (SVO). Experimental results demonstrated that our method provides real-scale information without compromising real-time performance, making it suitable for applications such as indoor navigation and industrial robot localization, where accurate absolute positioning is essential.