Underwater imaging
3D imaging of stationary and moving objects in turbid underwater environments
Optical imaging through water can be quite challenging. Especially once the water becomes turbid, the high degree of back-scattered light saturates the detector and the image can no longer be recognised.
Researchers at Heriot Watt University are investigating 3D imaging of objects in turbid underwater environments using a single-photon detector array which could revolutionise the clarity of imaging below the surface. This could greatly benefit offshore applications such as site surveys and inspections of windfarms and dams; search, security and defence, including in harbours and rivers; marine science and marine archaeology.
High resolution optical imaging in turbid underwater scenarios remains a major challenge. This is especially true for the cases of three-dimensional optical imaging, and the imaging of moving targets.
The main limitations in underwater active optical imaging are caused by absorption and scattering. One approach to overcoming the deleterious effects of scattering of light in water is to use short-pulse illumination and time-resolved single-photon detection, so that the returned photons can be distinguished from the scattering events.
The research team have demonstrated a fully submerged underwater LiDAR transceiver system based on single-photon detection technologies. The system uses silicon single-photon avalanche diode (SPAD) detector arrays to detect low photon returns (<10 photons per pixel) from the targets of interest.
The team have shown three-dimensional imaging by implementing bespoke image processing techniques, which achieved images of stationary targets with up to 7.5 attenuation lengths between the transceiver and the target.
Underwater Imaging
Dr Aurora Maccarone, Heriot Watt University, discusses the Underwater Imaging technology and its potential applications for offshore engineering, security & defence, marine science and marine archaeology.
Benefits
- 3D imaging capability
- Imaging of stationary and moving targets in turbid water
- The fully submerged system allows images to be constructed in real-time
Applications
- Offshore site surveys
- Windfarm inspection
- Search
- Defence and security
- Marine science
- Marine archaeology
Climate Change and Defence & Security
About our investigators
Professor Gerald Buller is leader of the Single Photon Research Group at Heriot-Watt University. His research interests are in single photon detection and its applications including quantum key distribution, quantum imaging, time-of-flight ranging and depth imaging.
Dr Aurora Maccarone is Assistant Professor at the Single Photon Research Group at Heriot-Watt University. Aurora is Research Fellow of the Royal Academy of Engineering, investigating state of the art single photon detector arrays for several underwater applications.