Two US university labs have developed a unique camera that can ditch the long lenses ore even telescopes to capture distant images, using holography technique called SAVI. It employs a single beam, multiple images and sophisticated software to capture detailed images from a distance.
The technique stands for ‘Synthetic Apertures for long-range, subdiffraction-limited Visible Imaging’ and it uses coherent light to brighten a distant spot and then uses algorithm to create high resolution image, thus making long lens redundant. It uses comparative pattern from a host of images of the spot taken from different locations.
Ashok Veeraraghavan, a Rice assistant professor and lead scientist, said it’s a step toward a SAVI camera. "Today, the technology can be applied only to coherent light… You cannot apply these techniques to take pictures outdoors… Our hope is that one day, maybe a decade from now, we will have that ability.”
The traditional camera uses larger aperture for a better resolution. “If you want an aperture that’s half a foot, you may need 30 glass surfaces to remove aberrations and create a focused spot. This makes your lens very big and bulky,” explained Ashok Veeraraghavan.
The new SAVI or “synthetic aperture” sidesteps long lens with a computer program the resolves the speckle data into an image. “You can capture interference patterns from a fair distance. How far depends on how strong the laser is and how far away you can illuminate,” said Ashok Veeraraghavan.
“By moving aberration estimation and correction out to computation, we can create a compact device that gives us the same surface area as the lens we want without the size, weight, volume and cost,” said Cossairt, an assistant professor of electrical engineering and computer science at Northwestern, who was part of the project.
Lead author Jason Holloway, a Rice alumnus who is now a postdoctoral researcher at Columbia University, said an array of inexpensive sensors and plastic lenses costing a few dollars may someday replace traditional telephoto lenses that cost more than $100,000 now. “We should be able to capture that exact same performance but at orders-of-magnitude lower cost,” he said.