5 ms·

While thinking about it, i realized, that our vision apparatus has an interesting feature: When you move your head, your field of sight moves with that motion.

While thinking about it, i realized, that our vision apparatus has an interesting feature: When you move your head, your field of sight moves with that motion. But when you hold your head still and only move your eyeballs, the field of sight stays constant, while the focus point (gaze point?) changes, scanning the still standing field of sight. Imagine replacing the eyeballs along with their mounting and motion with cameras. Every motion would translate the field of sight as a whole. Anyone knows, how this mechanism is called?

baxtr 4y ago
Damn. Now that I did that experiment I was reminded of my eye floaters. Thanks for that... My day is ruined. /s https://en.wikipedia.org/wiki/Floater https://en.wikipedia.org/wiki/Floater
- lagrange77 4y ago
  Good ol' faithful friends
GistNoesis 4y ago
In the radio domain, this is called beam-forming.
xeonmc 4y ago
gimbal? And the reflex for keeping the gaze fixed is oculovestibular reflex
- lagrange77 4y ago
  As a layman, i would say the gimbal mechanism merely lets you lock focus on some global coordinates, while moving your head around, but maybe i'm wrong.
numpad0 4y ago
Mind blown. Indeed: - when I move my head to (+30, +45), my brain reports viewport.LeftTop =(0,0), and, - when I move my eyes to (+30, +15), my brain reports viewport.LeftTop = (30, -15). But our eyes are built in such way that the whole lens and sensor assembly rotates, rather than having sensor fixed to the head and lens rotating, so it makes no sense. Framebuffer should always span from (0,0) to (size.x, size.y). Perhaps the framebuffer always covers the full viewing range, and DMA start addresses are dynamically determined by current eye positions, or perhaps even by feature matching?
- MereInterest 4y ago
  It gets even weirder when you consider blind spots. The hardware has a pretty big design flaw, that the signal wires are routed in front of the active sensors instead of behind. As a result, there's a big bundle that needs to pass through the sensor array, resulting in a blind spot. This is fixed in software, by interpolating nearby inputs before presenting it to the user (i.e. your conscious mind). Saccades also present a hardware limitation. During rapid movements, the eye can't focus correctly. To improve the overall UX, we throw away those frames entirely, reconstruct them with a linear interpolation of the next few frames, and call it a day. It does introduce some lag, but the user-level process is usually lagging behind anyways, and doesn't notice the input lag so long as we backdate the timestamps.
  - Someone 4y ago
    > To improve the overall UX, we throw away those frames entirely, reconstruct them with a linear interpolation of the next few frames Do we know that interpolation is linear? If so, in what coordinate system? Head? Single eye? One including gaze direction? One including what one is attending to (whatever that is)? I find it hard to believe it would be linear. Wouldn’t that mean that it would seem a rolling ball stops rolling during saccades? I wonder what kind of experiment could be used to research that.
  - yojo 4y ago
    The time stamp thing is especially crazy, and you can see it break down if you saccade to a ticking clock. This twitter thread made the rounds a while back, which lays it out in a nice incredulous rant: https://mobile.twitter.com/foone/status/1014267515696922624 https://mobile.twitter.com/foone/status/1014267515696922624
  - psd1 4y ago
    The hardware is designed completely iteratively, so it's - predictably - a mass of ossified hacks. The product team has no strategic vision: it's generally conservative, but sometimes a completely random idea gets into production. They do A/B testing but completely half-ass it, often they never deprecate the old version, and deciphering serial numbers requires a degree in microbiology. You'd think the environment would be perfect for disruption, but this actually is the new arrival and it's repeating all the mistakes of the incumbents! How the fuck this scales to billions I have no idea. The sysads must be getting overtime.
danparsonson 4y ago
Not any kind of relevant expert but I think what you're describing there is the combination of two things - the field of vision of your eyes, coupled with your proprioception, your awareness of your body and its position in space.
- lagrange77 4y ago
  Right, and some part of the brain seems to do some sort of Kalman filtering with those pieces of perception.
boloust 4y ago
If you move just your eyes, they can only rotate in effectively discontinuous jumps (saccades), during which you are basically blind. This limitation is present no matter how slowly you move your eyes. However, your eyes are perfectly capable of smooth motion if you stare at a fixed point and move your head or body. It seems the two systems were created by different teams that didn't communicate much.
alanbernstein 4y ago
Not an expert, but I think part of what you’re describing is an illusion. Our brains do a lot of work to trick us into thinking we see everything that we expect to be in our FOV. Blind spots demonstrate this. For me, when I turn my head, my apparent FOV rotates, while when I move my eyes, it does not. However, when my eyes are looking far right, I can no longer actually detect motion in the far left of my FOV. even though that part of the scene still feels like it’s visible, it isn’t. Anyway, I think the technology equivalent is just called stabilization. Again, our brains are really good at tricking us into not noticing it happening. But if you could view the “raw feed” from the optic nerves, it wouldn’t look anywhere near as clean as your description suggests.

baxtr 4y ago

Damn. Now that I did that experiment I was reminded of my eye floaters. Thanks for that... My day is ruined. /s https://en.wikipedia.org/wiki/Floater https://en.wikipedia.org/wiki/Floater

lagrange77 4y ago
Good ol' faithful friends

GistNoesis 4y ago

In the radio domain, this is called beam-forming.

xeonmc 4y ago

gimbal? And the reflex for keeping the gaze fixed is oculovestibular reflex

lagrange77 4y ago
As a layman, i would say the gimbal mechanism merely lets you lock focus on some global coordinates, while moving your head around, but maybe i'm wrong.

numpad0 4y ago

Mind blown. Indeed: - when I move my head to (+30, +45), my brain reports viewport.LeftTop =(0,0), and, - when I move my eyes to (+30, +15), my brain reports viewport.LeftTop = (30, -15). But our eyes are built in such way that the whole lens and sensor assembly rotates, rather than having sensor fixed to the head and lens rotating, so it makes no sense. Framebuffer should always span from (0,0) to (size.x, size.y). Perhaps the framebuffer always covers the full viewing range, and DMA start addresses are dynamically determined by current eye positions, or perhaps even by feature matching?

MereInterest 4y ago
It gets even weirder when you consider blind spots. The hardware has a pretty big design flaw, that the signal wires are routed in front of the active sensors instead of behind. As a result, there's a big bundle that needs to pass through the sensor array, resulting in a blind spot. This is fixed in software, by interpolating nearby inputs before presenting it to the user (i.e. your conscious mind). Saccades also present a hardware limitation. During rapid movements, the eye can't focus correctly. To improve the overall UX, we throw away those frames entirely, reconstruct them with a linear interpolation of the next few frames, and call it a day. It does introduce some lag, but the user-level process is usually lagging behind anyways, and doesn't notice the input lag so long as we backdate the timestamps.
- Someone 4y ago
  > To improve the overall UX, we throw away those frames entirely, reconstruct them with a linear interpolation of the next few frames Do we know that interpolation is linear? If so, in what coordinate system? Head? Single eye? One including gaze direction? One including what one is attending to (whatever that is)? I find it hard to believe it would be linear. Wouldn’t that mean that it would seem a rolling ball stops rolling during saccades? I wonder what kind of experiment could be used to research that.
- yojo 4y ago
  The time stamp thing is especially crazy, and you can see it break down if you saccade to a ticking clock. This twitter thread made the rounds a while back, which lays it out in a nice incredulous rant: https://mobile.twitter.com/foone/status/1014267515696922624 https://mobile.twitter.com/foone/status/1014267515696922624
- psd1 4y ago
  The hardware is designed completely iteratively, so it's - predictably - a mass of ossified hacks. The product team has no strategic vision: it's generally conservative, but sometimes a completely random idea gets into production. They do A/B testing but completely half-ass it, often they never deprecate the old version, and deciphering serial numbers requires a degree in microbiology. You'd think the environment would be perfect for disruption, but this actually is the new arrival and it's repeating all the mistakes of the incumbents! How the fuck this scales to billions I have no idea. The sysads must be getting overtime.

danparsonson 4y ago

Not any kind of relevant expert but I think what you're describing there is the combination of two things - the field of vision of your eyes, coupled with your proprioception, your awareness of your body and its position in space.

lagrange77 4y ago
Right, and some part of the brain seems to do some sort of Kalman filtering with those pieces of perception.

boloust 4y ago

If you move just your eyes, they can only rotate in effectively discontinuous jumps (saccades), during which you are basically blind. This limitation is present no matter how slowly you move your eyes. However, your eyes are perfectly capable of smooth motion if you stare at a fixed point and move your head or body. It seems the two systems were created by different teams that didn't communicate much.

alanbernstein 4y ago

Not an expert, but I think part of what you’re describing is an illusion. Our brains do a lot of work to trick us into thinking we see everything that we expect to be in our FOV. Blind spots demonstrate this. For me, when I turn my head, my apparent FOV rotates, while when I move my eyes, it does not. However, when my eyes are looking far right, I can no longer actually detect motion in the far left of my FOV. even though that part of the scene still feels like it’s visible, it isn’t. Anyway, I think the technology equivalent is just called stabilization. Again, our brains are really good at tricking us into not noticing it happening. But if you could view the “raw feed” from the optic nerves, it wouldn’t look anywhere near as clean as your description suggests.