What scientists learnt from 3-D lenses on praying mantis

APD NEWS

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A new form of 3-D vision in praying mantises revealed through tiny lenses may help improve robot sight, according to researchers.

With two teardrop-shaped, light-filtering lenses perched on their heads, the insects lashed out in lab experiments at images of tempting prey in a special 3-D film, the scientists said in the research published in Current Biology.

The insects' reaction to more images was then observed and the researchers learned that mantis vision works very differently to ours.

Also known as "stereopsis", 3-D or stereo vision helps humans and other creatures determine the distances to objects we see.

"Mantises only attack moving prey, so their 3-D doesn't need to work in still images," said Vivek Nityananda of Newcastle University, one of the authors of a study.

"We found mantises don't bother about the details of the picture, but just look for places where the picture is changing," he said in a video explaining the experiment.

This was the case even when each eye looked at two completely different images – an ability humans don't share.

According to fellow researcher Jenny Read, this was a simpler method of 3-D vision and could have implications for building lighter machines, such as drones.

"Current machine stereo algorithms require a lot of computing power," she said.

"Reducing the amount of computer power necessary means smaller, lightweight robots could use mantis stereo algorithms to detect depth."

'Fundamentally' different

The mantis is the only insect known to have stereo vision, but given its tiny brain, scientists have long suspected it must involve a simpler process.

Also known as "stereopsis", 3-D or stereo vision helps humans and other creatures determine the distances to objects we see.

Each eye sees an object at a slightly different angle, but the brain merges the two images together and uses the difference to calculate how far something is.

Other animals with this ability include monkeys, cats, horses, owls and toads, said the research team.

The mantis is the only insect known to have stereo vision, but given its tiny brain, scientists have long suspected it must involve a simpler process.

To test this, the team created special, tiny 3-D glasses out of blue and green-colored filters, and used beeswax to fit them to 10 adult insects.

The experiment revealed that mantis stereopsis "uses a fundamentally different computational algorithm", they said.

"Thus, while there is no evidence that mantis stereopsis works at all with static images, it successfully reveals the distance to a moving target."

(AFP)