Improving the perception of visual fiducial markers in the field using Adaptive Active Exposure Control

TL;DR

This paper presents a gradient-based active camera exposure control method to improve the perception of visual fiducial markers underwater, significantly enhancing localization accuracy for autonomous underwater vehicles under challenging lighting conditions.

Contribution

It introduces a novel adaptive active exposure control technique tailored for underwater environments, improving visual marker detection and localization accuracy.

Findings

Significant improvement in localization accuracy compared to existing methods

Effective handling of sharp lighting variations underwater

Enhanced foundation for subsequent image processing tasks

Abstract

Accurate localization is fundamental for autonomous underwater vehicles (AUVs) to carry out precise tasks, such as manipulation and construction. Vision-based solutions using fiducial marker are promising, but extremely challenging underwater because of harsh lighting condition underwater. This paper introduces a gradient-based active camera exposure control method to tackle sharp lighting variations during image acquisition, which can establish better foundation for subsequent image enhancement procedures. Considering a typical scenario for underwater operations where visual tags are used, we proposed several experiments comparing our method with other state-of-the-art exposure control method including Active Exposure Control (AEC) and Gradient-based Exposure Control (GEC). Results show a significant improvement in the accuracy of robot localization. This method is an important component that can be used in visual-based state estimation pipeline to improve the overall localization accuracy.