Tracking objects that look a lot like their surroundings is a big problem for many autonomous vision systems. AI algorithms can solve this camouflage problem, but they take time and computing power. A new camera designed by researchers in South Korea provides a faster solution. The camera takes inspiration from the eyes of a cat, using two modifications that let it distinguish objects from their background, even at night. This camera copied two adaptations from cats’ eyes: their vertical pupils and a reflective structure behind their retinas. Combined, these allowed the camera to be 10 percent more accurate at distinguishing camouflaged objects from their backgrounds and 52 percent more efficient at absorbing incoming light. While conventional cameras can clearly see the foreground and background of an image, the slitted pupils of a cat focus directly on a target, preventing it from blending in with its surroundings. In conventional camera systems, when there is adequate light, the aperture—the camera’s version of a pupil, is small and circular.
This structure allows for a large depth of field (the distance between the closest and farthest objects in focus), clearly seeing both the foreground and the background. By contrast, cat eyes narrow to a vertical pupil during the day. This shifts the focus to a target, distinguishing it more clearly from the background. The researcher’s 3D printed a vertical slit to use as an aperture for their camera. They tested the vertical slit using seven computer vision algorithms designed to track moving objects. The vertical slit increased contrast between a target object and its background, even if they were visually similar. It beat the conventional camera on five of the seven tests. For the two tests it performed worse than the conventional camera, the accuracies of the two cameras were within 10 percent of each other. The researchers created an artificial version of cat’s biological structure by placing a silver reflector under each photodiode in the camera. Photodiodes without a reflector generated current when more than 1.39 watts per square meter of light fell on them, while photodiodes with a reflector activated with 0.007 W/m2 of light.
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