this post was submitted on 24 Sep 2023
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Why can't we decrease our eye's FPS to get better night vision? (feddit.de)
submitted 1 year ago* (last edited 1 year ago) by Pantherina@feddit.de to c/asklemmy@lemmy.ml
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My phone is normally worse for color gradients and contrasts than my eyes. Also, normally it has worse nightvision.

But when decreasing the shutter speed, for example in OpenCamera, I get crazy night pics.

I see that when its dark my FPS goes down, I see less frames automatically and totally cant control that.

Could this mechanism be altered, to have even less FPS but more photons in the soup to get brighter sight?

Yes, trying to hack my eyes here. "Getting used to darkness" is normally the pupils getting wider, there are quite some interesting plants to do that but I havent heard of anything altering the brains image processing.

Edit

I learned:

  • in Nightsight we use the rod cells, which take longer to send a signal. That way they capture more photons, but the "FPS" is lower
  • you can trick your iris naturally to stay open, like the Pirates did (some plants like nightshades also do this, applied locally)
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[โ€“] jlh@lemmy.jlh.name 49 points 1 year ago* (last edited 1 year ago) (1 children)

They do. The eye doesn't have "frames per second", per se, because every neuron acts independently, instead of as a eye-wide "frame". But the rod cells that your eye switches to for night vision have slower activation time than the cone cells, allowing them more time to capture photons, before telling the brain about what it saw. Just like how your camera switches to longer shutter times for night vision to capture more photons, before sending them to the SD card.

Rod cells also respond more slowly to light than cones and the stimuli they receive are added over roughly 100 milliseconds. While this makes rods more sensitive to smaller amounts of light, it also means that their ability to sense temporal changes, such as quickly changing images, is less accurate than that of cones.

https://en.wikipedia.org/wiki/Rod_cell#Sensitivity

[โ€“] Pantherina@feddit.de 16 points 1 year ago (2 children)

Crazy! Thats it! Thanks a lot!

So its not the brain composing the image differently, but the actual chemical method the cells use to capture light. Will be hard to modify haha

[โ€“] Umbrias@beehaw.org 2 points 1 year ago (1 children)

Put another way conventional cameras work with cumulative sensors (at least for this conversation we can say they do) which record the total quantity of photons and their intensity being received in each spot. The shutter is the process of closing off light input and recording the data from the sensor. Technically there's an upper limit to how much light cameras can take in, which they'd asymptotically approach I imagine.

Your eyes don't work the same way. Each photodetector cell will send a signal when it reacts with a photon of sufficient energy (wavelength, intensity will increase the probability of reaction if im not mistaken) and send that signal to your brain. There's a lot of other complicated stuff going on, but at the end of the day your photo receptor cells are only so sensitive, and if light is below the threshold that will activate them, you'll mostly just get signal noise. This is true of conventional cameras too, but they are generally just tuned for a different purpose.

Animals with good night vision have highly reflective membranes behind their photo receptors to increase the probability of a photon interacting with a photo receptor, and often have different tuning on their whole eye optical systems that make them more sensitive, but also more likely to burn. There are always tradeoffs.

[โ€“] Pantherina@feddit.de 1 points 1 year ago (1 children)

Would suck to have night vision during the day haha!

Thanks for the info! So a NVG collects the light and then shoots it out again? Or also increases the capture surface?

[โ€“] Umbrias@beehaw.org 1 points 1 year ago

Night vision goggles usually are very sensitive to visible light yeah. Im not sure on exactly how the optics work but some modern ones are set up more like vr. Some are also sensitive to near infra red, and some see entirely in infra red. The latter are thermal imaging. The longer the wavelength you go (the more red) the more difficult it is to create sensors that receive a good image. You can imagine that putting a thermal eye in a warm blooded animal might be a bit difficult because the eye itself will be emitting light that overpowers the scene.

[โ€“] jlh@lemmy.jlh.name 1 points 1 year ago

Yeah, NVGs are probably the most accessible option.