Imaging the Southern Ocean: Rugged Cameras for Harsh Climates

Measuring Waves and Sea Ice with Ship-Mounted Machine Vision Systems

Sea ice observed from the deck of RSV Nuyina using the ship-mounted camera system. Credit: Alessandro Toffoli

The Southern Ocean, which surrounds Antarctica, plays a crucial role in regulating the Earth’s climate. It acts as a vast carbon and heat sink, absorbing approximately 40% of the carbon dioxide and around 60% of the excess heat taken up by the world’s oceans and seas. This has a significant influence on global weather patterns and the pace of climate change.

The Southern Ocean remains one of the most under-observed regions on our globe. Collecting reliable data in the polar regions is exceptionally difficult due to extreme weather, rough seas, strong winds, sea ice, and their remote location. These challenges make scientific research both technically demanding and logistically complex.

To address this lack of data, a team of ocean engineers from The University of Melbourne, in collaboration with the Australian Antarctic Division and International Researchers, developed an innovative solution: an autonomous, multi-camera monitoring system. To meet the unique demands of the application, the research team requested assistance from Adept Turnkey, to provide advice and components for several camera systems. These included three systems: a stereo pair, a bow camera, and a sea ice camera.

The stereo camera is mounted to a gunwhale and is primarily used for measuring surface waves.

The bow camera is mounted to the gunwhale and looks down at the bow and bow wave to measure ice thickness.

The sea ice camera is mounted on one of the highest decks adjacent to but outside the marine radars’ beam angle. It captures a large portion of the sea surface to measure sea ice extent.

All three systems are designed to meet the required imaging performance and to operate reliably when directly exposed to open ocean conditions and temperatures as low as –20°C. The systems are mounted to the gunwales and rails of an Antarctic ship and so have to be able to withstand and operate in the furious conditions expected in the Southern Ocean. It required a robust design to enable continuous, high-quality data collection on waves and sea ice, even in the harshest Antarctic conditions.

Adept Turnkey’s expert Vision Engineers identified several key challenges including: 

Extreme temperatures

• Electronics can be unstable and can also degrade quickly when operating in very cold and changing temperatures (-20C to 0C)
• Low temperatures can cause frosting and ice build-up on the optical window
• The wide fluctuation in temperature expected can also create image quality issues.

Sea Water

• Sea water in air is an extremely corrosive environment for metal and can cause rapid oxidisation of metal enclosures and metal connectors
• Airborne or splashed sea water can collect and create a salty film on the optical window

Impact and wash down

• The severe winds and water wash that can occur in storms at sea can put significant force and pressure on housings and cables
• The pressure and speed of winds and waves can cause water to infiltrate enclosures that are inadequately sealed

Ease of installation and maintenance

• Protecting from extreme environments can lead to increased mass and weight of the device to be mounted to a gunwale and make it more difficult to mount securely.
• Multiple cables make installation more complicated with a higher risk of failure
  
  

 

Stereo camera system mounted on the ship is Designed to withstand –20°C and rough sea. Credit: Alessandro Toffoli and Ippolita Tersigni

 

Professor Alessandro Toffoli, Project Researcher and Professor in Ocean Engineering at The University of Melbourne, said that a number of imaging systems needed to be integrated to capture both ocean and sea ice conditions simultaneously.

“We used a combination of paired stereo cameras and single cameras to observe the ocean and sea ice from the icebreaker RSV Nuyina during its voyages to Antarctica,” he said.

“The stereo cameras work like human eyes, capturing information about the ocean surface and allowing us to measure the size and shape of waves.”

Thermal imaging of the Antarctic sea surface reveals temperature differences. Credit: Alessandro Toffoli and Filippo Nelli

The synchronised stereo camera systems used robust 5 MP GigE industrial cameras supplied by Adept Turnkey along with high-impact, light weight stainless steel enclosures built to withstand extreme Antarctic weather and salt water. The enclosures were rated IP68 for full immersion to a depth greater than 1m and tested by Adept Turnkey engineers to ensure they met those specifications.

The enclosures were also fitted with a heater to combat low and widely ranging ambient temperatures and to avoid frosting/icing on the optical window. All signals and power were designed to run on a single ruggedised cable and the enclosure gland similarly rated to IP68. All in all the design accounted successfully for all the potential issues and provided reliable operation in harsh conditions.

To achieve the field of view and working distances required, the stereo camera systems were setup with a wide baseline configuration of several metres. To achieve this the cameras in each stereo pair were housed separately and mounted individually onto the ship’s gunwale. With the cameras being separated at some distance, PtP was used for synchronisation. The enclosures were mounted with rigid brackets designed to withstand the considerable forces expected from wind and waves and the stereo cameras were calibrated in-situ by the Antarctic Research team once mounted.

To interpret the imagery, scientists developed automated algorithms that extract key metrics from the ocean surface, such as wave height, direction, and length, as well as the size, type, and movement of sea ice. Because the cameras are positioned close to the ocean surface, they avoid the cloud interference that often limits satellite visibility. This proximity provides a continuous, highly detailed view that has previously not been possible in the polar regions.

“This system allows us to collect valuable ocean and sea ice data continuously during every trip, even when the ship’s main mission isn’t scientific,” Toffoli said.

“The Southern Ocean, especially around the sea ice zone, is one of the least observed parts of the world’s oceans.”

Large sea floats the Southern Ocean. Credit: Alessandro Toffoli

Numerical models have often struggled to provide accurate data in the marginal ice zone. In one instance, the ship passed through a polar cyclone, where the system recorded vigorous wave activity, up to nine metres high, even in areas completely covered in pancake ice and frazil slush. Existing models have predicted that wave motion would diminish rapidly under dense ice cover, but the research done by Toffoli and his group with Adept Turnkey’s cameras has revealed otherwise.

“The exciting part is that we can now gather this data even in sea ice zones, where traditional floating instruments often fail because they get crushed by the ice,” Toffoli said.

“By mounting our sensors on a ship, we can measure waves more thoroughly along the ship’s path, even in harsh ice-covered waters.”

A key component of the monitoring system is the bow-mounted camera that continuously observes sea ice as it fractures beneath the vessel.

“As the ship moves through the ice, the ice breaks up and large pieces often flip over,” said Toffoli.

“By analysing these flipping ice chunks, we can estimate how thick the ice is.”

“Ice thickness is a really important number for climate models because it helps determine how much heat and energy are exchanged between the ocean and the atmosphere.”

In addition to improving situational awareness at sea, the surface-level camera system is used to enhance the accuracy of satellite data and supported more reliable climate models.

“To check and improve the accuracy of satellite models, we need what’s called ‘ground truth’ data, real-world measurements taken directly from the environment,” Toffoli said.

“That’s where our surface-level camera system comes in. Mounted on Australia’s Antarctic icebreaker, the cameras collect reliable, high-quality data on waves and sea ice while being exposed to the harsh conditions that often damage traditional sensors.”

The images allow researchers to measure ice thickness. Credit: Alessandro Toffoli

As part of an Australian Research Council Linkage Infrastructure, Equipment and Facilities (LIEF) project, scientists and researchers from the University of Melbourne, working in collaboration with the Australian Antarctic Division, CSIRO, and other national and international partners, have continued to refine and expand the system.

The next phase of research focuses on further improving measurements of sea ice thickness and structure, contributing to a deeper understanding of the feedback mechanisms driving climate change in polar regions.

Adept Turnkey thanks Professor Toffoli and other members of his group for information in the writing of this article and for the opportunity to assist and contribute to a very worthwhile project. This project was a great opportunity for our engineering team to combine our skills in several technology areas to create a great outcome for our customer. Also a project that aligns with Adept Turnkey’s vision to use smarter imaging to improve lives.

If you are working on a project that could benefit from advanced imaging solutions, please get in touch and our experienced vision experts will be happy to help.