Enhancing borehole geological inspection with accessible web-VR and Danmaku in-video annotations

Borehole geological inspection is crucial for subsurface analysis, yet conventional methods often suffer from limited spatial context, hardware dependency, and lack of collaborative capabilities. This work introduces a lightweight, browser-based Virtual Reality (Web-VR) platform that enhances borehole inspection through three core contributions: (1) a novel rear-view panorama reconstruction algorithm using monocular video and optical flow estimation to simulate the previously traversed borehole wall; (2) a fully accessible Web-VR interface enabling immersive multi-angle viewing across mobile, desktop, and headset devices without requiring specialized hardware or installation; and (3) a real-time, Danmaku-style annotation system for spatially and temporally synchronized user comments, supporting voice and text input. Evaluated on real-world borehole footage, the system achieves real-time rendering and lightweight CPU-only processing, while qualitative feedback from industry professionals confirms its utility for collaborative interpretation and remote analysis. The proposed approach demonstrates promising potential for democratizing immersive geological tools and enabling efficient, collaborative subsurface inspections.