Distance Measurement for UAVs in Deep Hazardous Tunnels

TL;DR

This paper presents an enhanced optical flow-based distance measurement system for UAVs operating in deep, poorly-lit tunnels where traditional localization methods fail, enabling effective inspection of hazardous tunnel environments.

Contribution

The paper introduces a novel enhanced optical flow algorithm with prediction to improve UAV distance measurement in challenging tunnel conditions.

Findings

Improved distance measurement accuracy in deep tunnels.

Effective UAV localization in environments unsuitable for GPS or WiFi.

Enhanced optical flow algorithm performs well in low-light, feature-scarce tunnels.

Abstract

The localization of Unmanned aerial vehicles (UAVs) in deep tunnels is extremely challenging due to their inaccessibility and hazardous environment. Conventional outdoor localization techniques (such as using GPS) and indoor localization techniques (such as those based on WiFi, Infrared (IR), Ultra-Wideband, etc.) do not work in deep tunnels. We are developing a UAV-based system for the inspection of defects in the Deep Tunnel Sewerage System (DTSS) in Singapore. To enable the UAV localization in the DTSS, we have developed a distance measurement module based on the optical flow technique. However, the standard optical flow technique does not work well in tunnels with poor lighting and a lack of features. Thus, we have developed an enhanced optical flow algorithm with prediction, to improve the distance measurement for UAVs in deep hazardous tunnels.