Raptor Camera Gives Drones Eagle-Eye Predator Vision
A biomimetic camera system is inspired by super-zoom vision of eagles, hawks and other birds of prey.
Birds of prey like eagles or hawks are estimated to have eyesight at least five times stronger than humans. Tests have shown that an eagle can spot a rabbit on the ground from nearly two miles away - 3.2 kilometers to be exact. That's the equivalent, for humans, of spotting an ant on the ground from the top of a 10-story building.
So it's hard to decide whether this is good news or bad news: European scientists have developed a miniaturized camera lens system, inspired by eagle vision, that can potentially give surveillance drones the kind of telephoto raptor vision previously restricted to the animal kingdom.
Published this week in the journal Science Advances, the research involves a technique called foveated imaging, in which objects in the dead center of a given field of view are captured with supercharged acuity.
It can help to think of it like this: You know those point-of-view "eagle eye" effects you see sometimes in movies or nature programs? Where the sides of the image are blurred, but the target image in the center seems magnified?
Well, it turns out that effect is actually pretty accurate: This is how raptors with foveated vision see their prey when they're hunting - and it's the inspiration for the new miniaturized camera system.
"If we look at evolution, foveated vision is common with birds of prey," said researcher Simon Thiele, in an email exchange from the University of Stuttgart. "It seems to give an advantage especially for observation when the bird/drone has to be aware of its surroundings, but at the same time to able to gain a maximum of information about a point of interest."
By replicating the raptor vision with a series of tiny stacked lenses, Thiele and his team have created a kind of artificial eyeball that can be incorporated into cameras, sensors and robots.
"So we could be able to build drones which have the vision of eagles," Thiele said.
In addition to drones, the technology also has potential applications in the medical and industrial fields - anywhere where a very small camera needs to focus in tightly.
While traditional zoom lenses can also achieve high resolution, the foveated imaging technology has two other significant benefits. For one thing, these lenses are small, about the size of a grain of salt. Second, they can be 3D printed in a way that makes the entire camera apparatus much less expensive to construct.
"In our case, 3D printing has several advantages compared to conventional lens manufacturing," Thiele said. "Probably the most important one is that at the scale we fabricate the lenses, conventional methods are a lot more difficult, expensive and time-consuming. A conventional approach would require immense efforts and most likely cost 10 to 1,000 times as much."
In addition, the desired foveated imaging can't be achieved with single-lens solutions, according to fellow researcher Harald Giessen.
"One needs to stack several lenses, so-called doublets or triplets," he said. "As they have undercuts that are filled with air, it would be very difficult to fabricate them with methods other than 3D printing."
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