Bionic eyes to be a thing in the next decade? Possibly. Boffins mark sensor-density breakthrough
- Reference: 1590066012
- News link: https://www.theregister.co.uk/2020/05/21/bionic_eyes_on_the_cards/
- Source link:
Zhiyong Fan and his team developed a hemispherical artificial retina containing light-sensitive nanowires made from perovskite to mimic the photoreceptors of the human eye. In a [1]paper in Nature , they detail how the device can "see" by reconstructing images (the letters "E", "I" and "Y") viewed by the artificial eye.
[2]
A detailed structure of EC-EYE. a) Exploded view of EC-EYE and b) side view, complete with liquid metal wires. Diagram via: "A biomimetic eye with a hemispherical perovskite nanowire array retina", Nature, 20 May
Previous attempts to develop robotic eyes were limited by the fact the scientists created an artificial retina by laying out receptors on a flat plane and then attempted to fold or curve them, compromising the density of sensors, an [3]accompanying article explains .
Fan's team got around this problem by placing photosensors directly inside the pores of a hemispherical membrane of aluminium oxide.
"Thin, flexible wires made of a liquid metal sealed in soft rubber tubes transmit signals from the nanowire photosensors to external circuitry for signal processing. These wires mimic the nerve fibres that connect the human eye to the brain," the researchers revealed in the paper, "A biomimetic eye with a hemispherical perovskite nanowire array retina," which appeared in the 20 May edition of Nature .
The artificial retina detects an average of 86 photons per second, on a par with the sensitivity of photoreceptors in human retinas. The performance results from perovskite being a compound which shows great promise in optoelectronic and photonic applications, such as solar cells.
On other measures, the robotic eye out-performs its human counterpart, the researchers said. It can take 19.2 milliseconds to respond to a pulse of light and then 23.9 milliseconds to return to its inactive state when a pulse has ended. The response-and-recovery times show how quickly it might respond to light signals. The time for a human retinas ranges from 40 to 150 ms.
But the team's work is just the start. The paper is based on a proof-of-concept consisting of just 100 pixels, each with three nanowires. The authors say their design can be built with better resolution than human eyes by increasing the density of nanowires to more than 10 times the human equivalent.
In an accompanying news article, Hongrui Jiang of the Department of Electrical and Computer Engineering at the University of Wisconsin, said Fan and co's "work adds to the breakthroughs that have been made in the past few decades, which have been achieved by mimicking not only camera-like eyes (such as those of humans), but also compound eyes similar to those of insects. Given these advances, it seems feasible that we might witness the wide use of artificial and bionic eyes in daily life within the next decade." ®
[1] https://www.nature.com/articles/s41586-020-2285-x
[2] https://regmedia.co.uk/2020/05/21/eye2.png
[3] https://www.nature.com/articles/d41586-020-01420-7
Re: We have the technology
Maybe call it the "Quarter of a Billion Dollar Man" to account for inflation.
More interestingly, what is the liquid metal in the "wires"? Mercury? Gallium? Surely not Rubidium! The design is interesting, but how are they proposing to interface it with the rest of the brain? I think I'd prefer an external camera with a supercomputer that whispers in my ear: E.g. "Just to the right of you there's a really cute guy, they look interested." or "The coffee cup is on the table two inches in front of your middle finger." I think I could adapt to that, without having dangerous metals in my skull.
Re: We have the technology
"I think I'd prefer an external camera with a supercomputer that whispers in my ear: E.g. "Just to the right of you there's a really cute guy, they look interested." or "The coffee cup is on the table two inches in front of your middle finger." I think I could adapt to that, without having dangerous metals in my skull."
You might enjoy this Wired article from almost 2 decades ago.
https://www.wired.com/2002/09/vision/
"A HALF CENTURY OF ARTIFICIAL-SIGHT RESEARCH HAS SUCCEEDED. AND NOW THIS BLIND MAN CAN SEE."
Re: We have the technology
The links provided by El Reg say, "eutectic gallium–indium alloy." Sounds like galinstan.
Bionic ears exist now, so this isn't that far a stretch.
We call them 'hearing aids'
No, we call them "cochlear implants"
Who turned the lights out ?
is this article claiming that the eye can detect less than 86 photons /second? Surely not ...
Re: Who turned the lights out ?
See the incredibly beautiful study of Hecht, Shlaer, and Pirenne (1942) Energy, quanta and vision. J. Gen. Physiol. 20 819-840. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2142545/ Dark adapted human rod cells require between 5 and 8 quanta on average to produce a neural signal. After the effects of absorption by parts of the eye between the outside world and the retina this corresponds to an ability of the humans tested to detect between 54 and 148 quanta (i.e. that's all you need to see a light under optimal conditions - the integration time is about 100ms, so all the quanta have to arrive within 100ms for optimal performance).
Here is the relevant section of the paper's abstract:
"With these three corrections, the range of 54 to 148 quanta at the cornea becomes as an upper limit 5 to 14 quanta actually absorbed by the retinal rods. 3. This small number of quanta, in comparison with the large number of rods (500) involved, precludes any significant two quantum absorptions per rod, and means that in order to produce a visual effect, one quantum must be absorbed by each of 5 to 14 rods in the retina. 4. Because this number of individual events is so small, it may be derived from an independent statistical study of the relation between the intensity of a light flash and the frequency with which it is seen. Such experiments give values of 5 to 8 for the number of critical events involved at the threshold of vision."
Your truly,
A Vision Scientist.
Re: Who turned the lights out ?
Thank you for an illuminating response. :-)
Re: Who turned the lights out ?
Just to clarify my summary of the experiment, each rod only needs a single photon to initiate the signalling cascade, but we need between 5 and 8 rods to be activated before we have a conscious experience of a flash. The human visual system is pretty remarkable.
We have the technology
I wish they would remake the Six Million Dollar Man!