A trick that allows animals to focus on distant objects without losing a wider perspective could one day give drone aircraft sharper vision.
Inside an animal鈥檚 eye, an area at the centre of the retina known as the fovea has a higher concentration of light-sensitive cells than surrounding regions. Showing only the centre of a viewpoint in high focus prevents the brain from being overloaded by high-resolution information.
Now, a computer system that mimics this approach using hardware and software is being developed by Nova Sensors, a company based in California, US. It uses a 鈥渄etection tracking algorithm鈥� to identify windows of interest within a picture, applying tricks such as motion-tracking, tonal analysis and facial recognition.
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Lower bandwidth
These interesting areas are then maintained at the maximum resolution rate by the system鈥檚 image sensors, while anything outside is kept at a lower resolution. This not only conserves processing power but also reduces the amount of bandwidth needed to transmit video footage.
To decrease resolution, software directs neighbouring pixels to work as one, creating more blocky 鈥渟uperpixels鈥�. The superpixels can also be made to refresh less frequently, reducing the resolution further.
The system is currently being evaluated by the US military for use aboard uncrewed air vehicles. Mark Massie, president of Nova Sensors, says it could let a UAV track a moving object more efficiently, reducing the amount of information that is sent back to a human operator. Non-military uses could include vehicles and person tracking, he says.
Night vision
The first prototype developed by the company uses a 128 x 128 pixel camera that captures images 30 times per second over a 60掳 field of view. In tests, this was used to focus on human faces and follow the movement of a model train.
A second version uses a 320 x 256 pixel mid-infrared camera for military night vision, and a third system uses a 1024 x 1024 pixel camera and can create perspectives with multiple high-focus regions.
Robert Fisher, at the University of Edinburgh鈥檚 School of Informatics in the UK, says the idea has been tested previously but adds: 鈥淢ostly they are laboratory devices. Here it sounds like one has made it to the marketplace.鈥�
鈥淎nother potential area of application would be videophones,鈥� he adds. 鈥淜eeping the face at high resolution while the background has lower resolution and a lower refresh rate.鈥�
