AsianScientist (Mar. 26, 2018) – A team of researchers at Nanyang Technological University, Singapore (NTU Singapore) has developed a camera that can take sharp, color images without using a lens and color filters. By removing the need for a lens and color filters, this innovation could help make compact cameras and smart phones slimmer. Their research was featured on the cover of Optica.
In a conventional camera, optics made from glass or plastic lenses capture light and guide it onto the color filters and camera sensor to obtain sharp, color images. These lenses are usually bulky and expensive due to the precision manufacturing required.
Instead, a team of researchers led by Assistant Professor Steve Cuong Dang from NTU Singapore created an algorithm that can reconstruct a multi-colored image from light captured by a piece of ground glass and a a monochrome sensor.
The scientists created a library of ‘speckle patterns’ linked to each wavelength of light, including those in the infrared and ultraviolet spectrums which are not visible to the naked eye. They then ‘reverse engineered’ the light scattered by the translucent matt surface of the ground glass to obtain the original image that was projected on to it.
Dang said their new imaging technique could help to improve imaging applications in biomedical and scientific applications as well as opening new doors for other industries.
“Our technology can also reconstruct images in other multiple wavelengths invisible to the naked eye, like infrared and ultraviolet, which are used in imaging purposes for medicine, surveillance and astrophysics. It can also reconstruct images taken at the microscopic scale,” he explained.
“The unique feature of our camera is that it can capture any range of light spectrum, unlike existing cameras on the market which are pre-fixed. It is also less affected by optical alignment issues like conventional cameras, because there are no moving parts and no focusing optics.”
The research team used their technique to distinguish between two different apple juices which look identical to the naked eye, but have different colour spectrums signalling their difference in ingredients or freshness, for instance.
It could also be used for forensics, as the camera could be tuned to capture a wide spectrum, including near infrared and ultraviolet, to reveal clues or evidence invisible under normal circumstances.
“There are other potential areas of application where our technique could be useful. For instance, it could be used for food safety, where one can take a photo of fruits or meat in particular spectra to look for spots that are associated with chemicals or bacterial activity leading to spoilage,” said study first author Dr. Sujit Kumar Sahoo.
A patent has been filed for this new technology by NTU’s innovation and enterprise arm, NTUitive, and the research team will be engaging industry partners to see how they can adapt their technology for real-world applications.
The article can be found at: Sahoo et al. (2017) Single-shot Multispectral Imaging with a Monochromatic Camera.
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Source: Nanyang Technological University; Photo: Shutterstock.
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