Tiny round wide-angle lens outperforms its bigger brothers
By Ben Coxworth
September 26, 2013
When it comes to capturing visual information in photographs, you typically have two choices – use a wide-angle lens to capture as many parts of a scene as possible, or use a close-up lens to better capture the details of one of those parts. However, with a new camera system developed by engineers at the University of California, San Diego, you can do both at once. What's more, the lens used in this system is just one-tenth the volume of a conventional wide-angle lens.
The system utilizes a monocentric lens, consisting of two domed glass shells joined together so that their concave surfaces are facing in toward one another – the result is a one-piece lens that looks like "a perfectly round glass marble." Such lenses are already known for simultaneously having a wide field of view and being able to capture high-resolution images. This means that you could zoom in on a part of one of those wide-angle shots, and still be able to make out details. Additionally, the lenses produce little of the distortion that's common in photos shot with traditional fish-eye wide-angle lenses.
Unfortunately, however, in the past it has proven difficult to convert the optical output of monocentric lenses into electrical impulses that register on a camera's sensor. The UC San Diego team was able to get around this problem by running a bundle of glass optical fibers from the lens to the sensor. Those fibers were polished to a concave curve on one side, which allowed them to align perfectly with the lens' convex outer surface.
Additionally, there were concerns that the lens/fiber optics arrangement would present difficulties in focusing, although this turned out not to be the case.
In its present form, the ultra-wide-angle camera system keeps objects in focus from a range of half a meter to 500 meters (1.6 to 1,640 ft), while still producing exceptionally high-resolution images. A 30-megapixel system is in the works, however, and plans call for an 85-megapixel multi-sensor version which will be about the size of a walnut.
Once commercialized, the technology could find its way into applications such as unmanned aerial vehicles, or smartphone cameras.
Researchers at the California Institute of Technology have also had success in designing a system that allows microscopes to capture images that are both wide-angle and high-resolution. That system uses an array of LEDs to produce one wide-angle image that's actually a composite of 150 close-up images that have been digitally stitched together.