Fish-inspired electric camera can sees in total darkness

This is the elephant fish, which sees using a very sharp electric sense. [Image: Maik Dobiey / Uni Bonn]

Electric sense

Robots inspired by African elephantfish ( Gnathonemus petersii ) will be able to see through the dirty waters normally found in areas of environmental disasters or when it is necessary to search for objects in aquatic environments - whether because these objects are lost or because they require maintenance .

Instead of the optical images captured by traditional cameras, engineers and zoologists at the University of Bonn in Germany have designed a camera capable of generating "electric images," in which colors are detected as electrical signatures of objects, just as elephant fish do .

With an electric organ in the tail, the fish generates short electrical pulses up to 80 times per second. Electroreceptors on your skin, and especially on your chin, resembling a trunk, measure how the pulses are modulated by the environment.

With this "electric sense," fish can estimate distances, perceive shapes and materials, and even distinguish between living and dead objects. In fractions of a second, he uses the electric pulses to detect where the mosquito larvae, his favorite prey, are hiding in the bottom of his habitat.

Electrical Camera

Martin Gottwald constructed a bionic camera by drawing on the two types of eletroreceptors that the elephant fish uses in their active electrolocalization: One measures the intensity of the electrical signal and the other the waveform of the pulse.

Combining these two signals, Gottwald discovered that it is possible to produce "electric colors," analogous to the visual colors detected by the human eye, only by means of electrical signals rather than visible light.

"With this bionic electric camera it is possible to photograph 'electric images' of objects without any light, even in an obscure environment, which also allows an analysis of the electrical and spatial properties of the objects represented," says Professor Gerhard von der Emde.

"Additional assessments have shown that electrical images can also be used to determine the 'electrical strokes' of measured objects, which, similar to their optical contours, can provide shape and orientation information," Gottwald said.

Electric field lines that scatter around the camera and a plant stem are shown in bluish-white colors. They run from the back end transmission electrodes to the measuring electrodes in the front area and toward the center part of the (gold) electric camera. [Image: Martin Gottwald / Hendrik Herzog]

Robots, drones and medical applications

Tests have shown that the camera-based system is capable of identifying various natural objects such as fish, plants or wood, as well as artificial objects such as aluminum or plastic spheres or rods.

Because they are not dependent on light, none of the parameters used by the camera is affected by the darkness or turbidity of the water.

In addition to allowing the development of inspection drones or robots to operate in hazy or misty environments, the team sees many other applications for electric cameras, including material control, device monitoring, and medical applications.

Bibliography:  A bio-inspired electric camera for short-range object inspection in murky waters Martin Gottwald, Hendrik Herzog, Gerhard von der Emde   Bioinspiration & Biomimetics   DOI: 10.1088 / 1748-3190 / ab08a6