Country for PR: Japan
Contributor: Kyodo News JBN
Thursday, March 10 2022 - 19:00
Artificial Retinal Device Mimics Human Optical Illusions: WPI-MANA
TSUKUBA, Japan, Mar. 10, 2022 /Kyodo JBN-AsiaNet/--

A team at the International Center for Materials Nanoarchitectonics (WPI-MANA) 
has developed the first-ever artificial retinal device that increases the edge 
contrast between lighter and darker areas of an image, using ionic migration 
and interaction within solid. The device has the potential for use in 
developing compact, energy-efficient visual sensing and image-processing 
hardware systems capable of processing analog signals.


Recently artificial intelligence (AI) system developers have shown much 
interest in research on various sensors and analog information-processing 
systems inspired by the human senses. Most AI systems require sophisticated 
software and complex circuit configurations, including custom-designed 
processing modules. The problem with these systems is that they are large and 
consume much power.

The team built a multiple ionic device system, each of which had a lithium 
cobalt oxide channel arranged on a common lithium phosphorus oxynitride 
electrolyte. Because of the migration of Li-ions between the channels through 
the electrolyte, the devices were highly interactive, similar to human retinal 
neurons such as photoreceptors, and horizontal and bipolar cells. Input voltage 
pulses caused ions within the electrolyte to migrate across the channels, which 
changed the output channel current.

The device was able to process input image signals and produce an image with 
increased edge contrast between darker and lighter areas. This is similar to 
the human visual system's ability to increase edge contrast between brightness 
differences by means of visual lateral inhibition.

The human eye produces various optical illusions associated with tilt angle, 
size, color and movement, in addition to darkness/lightness, and this process 
is believed to play a crucial role in the visual identification of different 
objects. The artificial retinal device the team created could be used to 
reproduce these types of optical illusions. They hope to develop visual sensing 
systems capable of performing human retinal functions by integrating their 
device with other components, including photoreceptor circuits.

This research was conducted by Tohru Tsuruoka (Chief Researcher, Nanoionic 
Devices Group, WPI-MANA, NIMS), Kazuya Terabe (MANA Principal Investigator, 
Group Leader, Nanoionic Devices Group, WPI-MANA, NIMS) and their collaborator.

Research Highlights Vol. 74


Source: International Center for Materials Nanoarchitectonics (WPI-MANA), 
National Institute for Materials Science (NIMS)