Engineering news
An ROV inspecting underwater oil and gas equipment
A new subsea camera has been developed that can see two to three times further under water than existing cameras and calculate distances to objects, making it easier to carry out subsea inspections and maintenance.
Researchers from SINTEF, an independent Norwegian research organisation, are currently working together with industry partners in Europe to develop sensors and lasers for the new underwater camera.
The camera achieves three times more distance through 'range gated imaging'.
"In underwater imaging, the main problem is that range is limited due to dissolved particles (plankton, mud etc.) in the water that reflect light back and obscures the target. This is similar to driving in the fog - increasing the light from the headlights will not provide a clearer image, rather only more light from the fog," explained Jens Thielemann, project manager at SINTEF.
"What we do is to emit the light as short pulses, and exploiting that the light is reflected from the particles/fog before it is reflected from the target. Thus, we can simply "close our eyes" for the time when we are getting light from particles/fog only. By in addition measuring the time until the light hits the target, we are capable of recovering depth information."
To test the camera, researchers constructed a frame which they placed on the seabed in Oslo Fjord in an area characterised by turbid (cloudy) water.
They took pictures of a target using the new prototype and compared them with those taken by a standard camera. SINTEF said that even the first version of the new system produced much clearer images than the standard system.
Above left: an image of a chessboard pattern taken by a standard camera at a distance of 7.5 metres. Above right: an image of the same object taken by the new camera prototype.
The camera can also be installed on the hulls of surface vessels, or on ROVs, in order to monitor keys areas of the seabed.
Thielemann said: "The new camera will provide better general and detailed imaging, and an entirely different database to that we are used to.
"The biggest problem with traditional cameras is that their range is reduced in poor visibility, particularly in coastal waters made turbid by suspended sand and clay particles. Such cameras have a very limited range under these conditions", says Thielemann.
SINTEF said the prototype camera is based on the "smart assembly of existing technologies", although the researchers will have to make some key improvements during the next two years.
"The new images provide better data and information. High-quality visual imaging also makes it easier to communicate the information to external parties," said Thielemann. "For example, occurrences of dead organisms on the seabed must be reported to the authorities, and in such cases it helps to have a picture."
The prototype camera, developed as part of UTOFIA - a project to develop a compact, easy to use and cost-effective underwater imaging system for turbid environments - will form the basis of a new type of commercial camera technology.
The ultimate aim is to produce a camera with a volume of between five and ten litres.
The components for this technology have been developed at a number of centres across Europe, including Italian laser experts Bright Solutions, and UK sensor experts from Odos Imaging, while SINTEF has assumed responsibility for project management, assembly of the components and image analysis.
New tests will be carried out in Copenhagen in February 2016, and in the summer the first version of the camera will be ready – based on specially-tailored components that will make it lighter, more compact and more powerful than the prototype.