Artificial Retinal Device Mimics Human Optical Illusions: WPI-MANA

TSUKUBA,Japan,March 10,2022 -- A team at the International Center for Materials Nanoarchitectonics (WPI-MANA)has developed the first-ever artificial retinal device that increases the edgecontrast between lighter and darker areas of an image,using ionic migrationand interaction within solid. The device has the potential for use indeveloping compact,energy-efficient visual sensing and image-processinghardware systems capable of processing analog signals.

(Image: https://kyodonewsprwire.jp/prwfile/release/M105739/202203017969/_prw_PI1fl_p63mh2x3.jpg)

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

The team built a multiple ionic device system,each of which had a lithiumcobalt oxide channel arranged on a common lithium phosphorus oxynitrideelectrolyte. Because of the migration of Li-ions between the channels throughthe electrolyte,the devices were highly interactive,similar to human retinalneurons such as photoreceptors,and horizontal and bipolar cells. Input voltagepulses caused ions within the electrolyte to migrate across the channels,whichchanged the output channel current.

The device was able to process input image signals and produce an image withincreased edge contrast between darker and lighter areas. This is similar tothe human visual system's ability to increase edge contrast between brightnessdifferences 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 processis believed to play a crucial role in the visual identification of differentobjects. The artificial retinal device the team created could be used toreproduce these types of optical illusions. They hope to develop visual sensingsystems capable of performing human retinal functions by integrating theirdevice with other components,including photoreceptor circuits.

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

Research Highlights Vol. 74: https://www.nims.go.jp/mana/research/highlights/vol74.html

MANA E-BULLETIN: https://www.nims.go.jp/mana/ebulletin/

View original content:https://www.prnewswire.com/news-releases/artificial-retinal-device-mimics-human-optical-illusions-wpi-mana-301499691.html