Scientists image in 3D with single-pixel detectors
Researchers from the University of Glasgow’s School of Physics and Astronomy have found a way to make sophisticated 3D images based on cheap detectors with just a single pixel. The technique was outlined in a report published today in the journal Science.
The technology could be used to create much more affordable forms of 3D imaging in the future. In addition, by using detectors capable of sensing frequencies beyond visible light, it could open new possibilities in other fields including medicine and geography.
Single-pixel detectors in four different locations are used to detect light from a data projector, which illuminates objects with a rapidly-shifting sequence of black-and-white patterns. The images contain shadows that give clues about the 3D shape of the object. Combining the four images using the ‘shape from shade’ technique creates a full 3D image of the object.
Professor Miles Padgett, Kelvin Chair of Natural Philosophy at the University and lead of the project, said: ‘Conventional 3D imaging systems which use multiple digital camera sensors to produce a 3D image from 2D information need to be carefully calibrated to ensure the multi-megapixel images align correctly. Our single-pixel system creates images with a similar degree of accuracy without the need for such detailed calibration.’
The technique the team use is called 3D computational imaging or ‘ghost’ imaging, and the system they have created can produce detailed images of objects in just a few seconds.
One of the primary benefits of using the new technique over more conventional 3D imaging techniques is that there exists single-pixel detectors that can image wavelengths beyond the visible range, reaching wavelengths from X-ray to terahertz.
Lead author on the paper, Baoqing Sun, of the University’s School of Physics and Astronomy, said: ‘Single-pixel detectors which cost just a few pounds each are now capable of producing images across a far wider spectrum than 3D imaging systems currently on the market which cost tens of thousands of pounds.’
The system’s capabilities and low cost could make it a valuable tool for a wide range of industries.
Research assistant Matthew Edgar, who contributed to the paper, said: ‘A more portable version of the system could be created quite easily, making it much more practical to use outside the lab. It could be used to look for the telltale gases which leak from the ground where oil can be found, for example, or it could be tuned into the terahertz range to probe just below the skin to search for tumours or other medical conditions.’
Work is continuing on the system with the idea to potentially commercialise it in the future.
The team’s paper, ‘3D Computational Imaging with Single-Pixel Detectors’, is published in Science.