378 pixels, 1bpp
The Phosphenes[0] patients sense will depend on what is left of the retina. People using earlier systems reported some interpolation happened. Maybe that is true of this device too.
[0] - that is the name for the image the brain manifests in response to signals received by the visual cortex. Most of us experience them when we close our eyes and rub them, or maybe just see stuff that is unreal.
The interpolation would tend to at best half a pixel? And the phosphor lag (like on a tube) would be an issue surely?
Are there instances of single eye outcome where the subject has drawn perceived image so we can understand how this exposes into conscious visual stimuli?
Even just a flash on the left == left object vs flash on the right == right object would be a useful signal compared to zero. But describing it as "vision" would be stretching it. 378 pixels is a few letters at 10x18 so it's 2-3 words. Again, massive gains on nothing, but it's beyond "large print" its "large print with a magnifying glass" and it might be phosphor burn colour against black or a foggy field, or a number of things.
To be clear, this is amazing stuff and hats off to anyone who helped make it happen, but let's not assume we're in "snow crash" territory just yet.
The lag would be in signal processing external to the user.
Interpolation would be more transparent, much like it is for you right now. There are no phosphors in tubes in any of this.
I made no such "snow crash" assumption.
Users of devices like this have described their experiences and those are not generally big square pixels.
Think of those more like points the brain can do something with.
The chip stimulates the remaining neuro-signal entities present in the damaged retina. I doubt there is a 1:1 relationship between those and the signaling points on the chip.
When the company can do better than on/off bright/contrast, the overall experience should improve dramatically. There will be more signal points (1024 ish?) and those having variable output levels will give the users visual cortex a whole lot more to work with.
About the only analogous thing I can come up with is cochlear implants. Those have a number of signal points that seems a lot smaller in number than expected. That was certainly my take. The more of those there are, the more concurrent sounds can be differentiated. A greater sense of timbre, in other words, becomes possible.
Any chance you could explain why this can only send black and white. Is colour a capability that could be added in the future?
I am speculating here.
The reason for it being a two level device at present is likely due to it being mostly research and not so much engineering.
They say their next chip will deliver grey scale and many more signal points.
My guess on color is one or more of the following is true:
[0]The color info is normally sent via the color sensitive cells now damaged and we have yet to understand how that signal enters the nerves we can send a signal to.
[1]It may be that we need a far smaller, more precise signal point to achieve color. Current tech stimulates many nerve endings. This was the basis for my interpolation comment above. Basically, each pixel stimulates an area of the damaged retina which contains a great many possible signal points if it were possible to stimulate them individually. Because so many are stimulated all at once, the subject perceives white phosphines rather than colored ones.
An analogy would be the colors on a CRT. A broadband beam would light them all up, yielding monochrome vision. A narrow beam can light up a few or just one, yielding color.
One thing I just realized writing this is our blue sensor cells are scattered about, not well clustered like the green and red ones are.
Maybe current users see a bit of color at the very extent of the artificial visual field due to a failure to hit the necessary blue cells...
[2] It may be some sort of pulse is needed to encode colors. And perhaps the current signaling is continuous.
Hopefully, we get an answer from the team.