A cheap, small and portable sensor has been made by some US scientists to help the automobile Industry avoid collision. The scientists have used metamaterials to construct the imaging system, which samples infra-red and microwave light.
This system which has no lens and instead combines a metamaterial mask or aperture and complicated mathematics to generate an image of a scene was developed by a graduate student John Hunt and colleagues at Duke University in North Carolina. John told the Science podcast that “Then we use some very elegant mathematics which was developed in computational imaging to turn that data into a 2D picture.” He also added that the wavelength was very fast when the sampling was done electronically.
The Metamaterials that was used are substances that have properties purposefully designed rather than determined by their chemistry. The advantages of the sensor in this research is that it compresses the images it captures in contrast to current compression systems, which only squash images after they are taken.
It is understood that most imaging systems, such as those found in digital cameras, use a lens to focus a scene on a sensor studded with millions of tiny sensors. Therefore, more sensors means more detail is captured and, generally, produces a higher resolution image. John said that the usual practice is that the imaging system could capture about 10 images per second and compressed the information as it was gathered, with most other image compression systems, such as the widely used Jpeg format, are applied after an image has been snapped.
While imaging systems that capture infra-red and microwave wavelengths already existed, said Mr Hunt, they were typically expensive, bulky or complicated to build.
By contrast, the Duke imaging system used a thin strip of metamaterial mated with some electronics and processing software. Although it did not yet work with visible wavelengths of light, Mr Hunt said it could lead to a range of cheap, small, portable sensors that could find a role in many different fields. The aperture is used to focus different wavelengths of light in different parts of a scene onto a detector. The different frequencies in the scene are sampled sequentially. This sampling helped to work out the distribution and mix of light wavelengths and their relative intensities found in a scene.
According to Mr Hunt, “a research paper detailing the work has appeared in the journal Science (See publication) and that the good thing about the emergence of this innovative systems using sensor is that, you could build an imager into the body of a car to do collision-avoidance imaging or you could have a cheap handheld device to look through walls for wires and pipes.”
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