Reconfigurable Robots for Scaling Reef Restoration

Coral reefs are under increasing threat from the impacts of climate change. Whilst current restoration approaches are effective, they require significant human involvement and equipment, and have limited deployment scale. Harvesting wild coral spawn from mass spawning events, rearing them to the larval stage and releasing the larvae onto degraded reefs is an emerging solution for reef restoration known as coral reseeding. This paper presents a reconfigurable autonomous surface vehicle system that can eliminate risky diving, cover greater areas with coral larvae, has a sensory suite for additional data measurement, and requires minimal non-technical expert training. A key feature is an on-board real-time benthic substrate classification model that predicts when to release larvae to increase settlement rate and ultimately, survivability. The presented robot design is reconfigurable, light weight, scalable, and easy to transport. Results from restoration deployments at Lizard Island demonstrate improved coral larvae release onto appropriate coral substrate, while also achieving 21.8 times more area coverage compared to manual methods.

Close-Proximity Underwater Terrain Mapping Using Learning-based Coarse Range Estimation

This paper presents a novel approach to underwater terrain mapping for Autonomous Underwater Vehicles (AUVs) operating in close proximity to complex 3D environments. The approach leverages a coarse learning-based scene range estimator from monocular images, which can filter transient objects such as fish and lighting aberrations. The proposed methodology then creates a probabilistic elevation map of the terrain using a learning-based scene range estimator as a sensor. The approach considers uncertainty in estimated scene range and robot pose as the AUV moves through the environment. The resulting elevation map can be used for reactive path planning and obstacle avoidance to allow robotic systems to follow the underwater terrain as closely as possible. The performance of our approach is evaluated in simulation by comparing the reconstructed terrain to ground truth reference maps in an photo-realistic underwater environment. The method is also demonstrated using field data collected within a coral reef environment by an AUV.