Our world depends on underwater infrastructure. Structures, pipelines, and internet cables are essential to our day-to-day life and require regular range inspection and maintenance. Underwater robots offer a promising solution for inspection—especially in places too remote or dangerous for human divers.
However, inspection robots are only as good as their sensors. It is often crucial to build dense 3D maps of the scene, but most 3D sensors such as LiDAR or RealSense are useless in undersea environments because water blocks infrared light. Sonars are great for long-range mapping, but face challenges with resolution and multi-path effects in close-range imaging scenarios.
Introducing: The Illuminator. We designed an underwater, visible light time-of-flight camera system to enable high-resolution, close-range 3D imaging for underwater robots. Our system consists of two components: an illumination module with high-power LEDs modulated at 24MHz, and an imaging module comprising a depth-capable camera, a high-performance microcontroller, and an Ethernet interface. Over the course of this project, we performed a conceptual study to pick the optimal imaging method and key components, designed individual circuit boards, conducted subsystem-level testing, and finally evaluated our entire system in realistic underwater imaging scenarios.