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Miniature Colour Camera via Flat Hybrid Meta-Optics: a small camera that captures high quality images

Published on 6.6.2023
Tampere University
Kuva koostuu useista pienistä kuvista. Keskellä mies, joka katsoo pienen linssin läpi. Alalaidassa henkilö, joka ottaa kuvaa järjestelmäkameralla. Ylälaidassa pieni negatiivi. Myös muuta valokuvaukseen liittyvää kuvitusta, geometrisiä kuvioita.
Because rapid technological change, old equipment, such as cameras, need to be rethought. Making cameras smaller and lighter while maintaining high image quality is highly important for their integration into mobile platforms, such as mobile phones, drones, and handheld medical devices. Industry revolution 4.0 is a study that conceptualises the rapid change of technology, industries, and societal patterns characterised by the merging of technologies via miniaturisation and embedded systems.

Researchers Karén Eguiazarian, Vladimir Katkovnik, Seyyed Reza Miri Rostami and Igor Shevkunov from Tampere University have been developing hybrid optics that are more than a hundred times smaller than traditional compound lenses. The study has been done together with researchers Samuel Pinilla from the Science and Technology Facilities Council in Harwell, UK, and Arka Majumdar and Johannes E. Fröch from the University of Washington in Seattle.

“Modern cameras are optimised to produce high-quality images. They are typically composed of many lenses to compensate geometric and chromatic aberrations. However, that increases the size and weight of the camera. In the study, our aim was to make cameras smaller and lighter while maintaining a high image quality,” Eguiazarian describes.

Extensive research on this topic has recently been made in optics and photonics research. The race for miniature colour cameras, which employ flat diffractive meta-optics instead of conventional refractive lenses, has rapidly developed the end-to-end design framework that is using modern neural networks.

High-quality imaging with only two optical elements

Although a large body of work has shown the potential of this technology, the reported performance is still limited due to the fundamental restrictions of diffractive meta-optics, the mismatch of simulated and resultant experimental point spread functions, and calibration errors.

“A solution to this conundrum is computational imaging, where a digital backend augments the deficiencies of the optical components and improves image quality. This has thus become a multidisciplinary research field at the intersection of optics, mathematics, and digital image processing,” Eguiazarian says.

In the study, a novel optics design methodology is proposed to solve these limitations and demonstrate a miniature colour camera via flat hybrid meta-optics (lens + meta surface). The resulting camera achieves the high quality of full-colour imaging for a 5 mm aperture optics with a focal length of 5 mm.

This means that high-quality imaging is now available with only two optical elements which in turn is seen in the dimensions of the miniature camera.

“The superior quality of the images captured by the hybrid meta-optical camera is demonstrated as compared to the compound multi-lens optics of commercial cameras. Despite its miniature size, images produced by our camera are of superior quality,” Eguiazarian points out.

One of the lifelong outcomes of the project is the contribution to resource-wise sustainable development. Since the approach of the study requires fewer lenses, the results use significantly less glass or plastics.

Additional information:

Karén Eguiazarian
karen.eguiazarian [at] (karen[dot]eguiazarian[at]tuni[dot]fi)
+35840 8415 663