A zero breakthrough! Quantum radar achieves underwater 3D imaging for the first time
Scientists have developed a novel technique that, for the first time ever, uses quantum detection to capture 3D images while submerged underwater, according to a press release from Optica.
The research results, titled "Submerged single-photon LiDAR imaging sensor used for real-time 3D scene reconstruction in scattering underwater environments (Submerged single-photon LiDAR imaging sensor used for real-time 3D scene reconstruction in scattering underwater environments)," published in optica.
The system is called LiDAR and it works by using a laser to measure the time it takes for light to reflect back from objects in the environment.
Submerging a lidar system in water is not an easy task, as water can restrict light and scatter particles, making it difficult to capture a clear image. Yet single-photon detection - a quantum-based technology - has very high penetration power and works even in low-light conditions.
This time, a team of researchers from Heriot-Watt University, UK, and the University of Edinburgh used an array of single-photon detectors to detect reflected pulsed illumination, which allowed them to detect low light and create detailed 3D images of objects even in poorly lit areas, such as murky waters.
By measuring the time of flight in very precise picoseconds, the team can distinguish minute details of objects in a scene without blurring the image, even in places where the water is very murky.
The lidar system works by emitting a pulse of green laser light to illuminate the environment.
(a) Schematic diagram. The optical unit consists of a fiber-optic collimation assembly (FCP), an optical diffuser (D), lenses (L1 and L2), band-pass filters (BP), and a SPAD detector array. The optical unit is housed in a watertight enclosure and connected to the equipment outside the tank via an "umbilical cord". (b) Photograph of the SPAD detector array-based optical device.
The experimental schematic shows the submerged transceiver, the external control and source modules, the target position and the lens.
The method also allows the researchers to distinguish photons reflected by the target from those reflected by particles in the water: this makes it particularly suitable for 3D imaging in highly turbid waters, where optical scattering can disrupt image contrast and resolution.
The team says the breakthrough technology has many potential applications, including inspecting underwater facilities, monitoring underwater archaeological sites, and enhancing security and defense measures. It could also help reduce pollution and minimize human impact on the marine environment, as it enables monitoring without humans.
The fact that this approach requires thousands of single-photon detectors, all of which generate hundreds of events per second, makes it extremely challenging to retrieve and process the data needed to reconstruct 3D images in a short period of time, especially for real-time applications. However, the team developed algorithms specifically for imaging in highly scattering conditions and used them in conjunction with widely available graphics processing unit (GPU) hardware.
The quantum lidar prototype obtained real-time 3D images while fully submerged in water
They tested the system at three different turbidity levels and found that it successfully imaged targets up to 3 meters away. Now, they are focusing on scaling down the system to make it suitable for integration into underwater vehicles, which will expand its possible applications.
This innovative technology represents a significant advancement in the field of underwater imaging as it allows for more detailed and accurate monitoring of the underwater environment.
As the technology continues to improve, it could have a significant impact on a range of industries: it will cover scientific research in energy, defense, environmental protection and more.
Reference links:
[1] https://www.techtimes.com/articles/291234/20230506/new-quantum-detetction-capture-3d-images-underwater.htm
[2]https://opg.optica.org/oe/fulltext.cfm?uri=oe-31-10-16690&id=530374
[3]https://interestingengineering.com/innovation/quantum-lidar-prototype-acquires-images-while-underwater
