4 ms·

I do wonder what the limit is in visual “framerate”. Normal light seems very smooth, but I can easily pick up on individual “frames” if I wave my finger under a

by snazz 8y ago

I do wonder what the limit is in visual “framerate”. Normal light seems very smooth, but I can easily pick up on individual “frames” if I wave my finger under an older fluorescent light (which should be running at 50-60Hz to match mains power if I understand it correctly).

baroffoos 8y ago
The eyes don't have a framerate. A video at 60fps looks smooth but a single black frame on a white video is visible even at much higher fps. If I move my mouse quickly in circles on a 60fpx screen it looks like I have 10 individual cursors in a ring but if I move my finger quickly in circles it looks like I have a slightly transparent ring shaped finger with no gaps in between, I can see the smooth curve of the path that my finger took which would have to be captured at an incredibly high framerate to display on a monitor.
- psandersen 8y ago
  A bit off topic but I've been thinking there has to be a better way of handling this at the LCD controller level here... Currently, a 60hz screen isn't perfect and pixel overdrive will be used to reduce motion blur. In effect, there are more 'unique intermediate frames' being displayed as the system tries to approximate the discrete input frames physically. The actual blur on fast-moving content on a modern screen is huge... Ignoring latency for a moment, if a controller has the previous and next frame plus motion vectors and knowledge of the precise pixel response and decay curves for the monitor... it should be possible to continuously adjust the current/voltages(?) to every pixel to better approximate what a much higher refresh rate low motion blur panel would look like on high fps content. Can't remove blur but can make motion continuous rather than a stair step. A kind of smart motion interpolation + overdrive implementation. The assumption is the higher fps the more linear the motion is frame to frame. 30 to 60fps interpolation should have more noticeable abnormalities than 120 to 1000hz.
  - londons_explore 8y ago
    I'd like to see a demo of this... I doubt one could make it work for computer graphics (since motion vectors aren't easily accessible), but when displaying video the results could be good, although users seem to dislike content with interpolated generated frames, and perhaps your proposed tech could get a similar response.
    - psandersen 8y ago
      Arguably computer graphics are the best candidate since many engines already have a velocity buffer for effects like temporal anti-aliasing and motion blur... would need API integration though. My hunch is motion interpolation is preferred at high fps. E.g. a high action scene at 30 fps will need a lot more information to be filled in and has likely already been mastered with the target frame rate in mind (camera shutter speed etc). But 120hz or more content will have very little motion between frames, and this motion will be far more linear (e.g. a finger might move 1cm between frames, but doesn't bend so less motion artefacts). So 120hz content upscaled to 960hz+ would be much closer to native 960hz content and preferable to displaying at the original 120hz. A logical implementation would be VR headsets with a built-in DSP.
  - pjc50 8y ago
    The individual pixels are only row-column addressable, unfortunately.
  - tk75x 8y ago
    https://www.svp-team.com/wiki/Main_Page https://www.svp-team.com/wiki/Main_Page This came to mind
chowells 8y ago
I have an idea to test, but I don't have the kind of electronics background to construct the necessary rig affordably. Or possibly to identify it if one exists already. Here's my thought: connect a laser to a high frequency switch, similar to what you'd find in a PWM controller. Then rig the laser to move such that the beam traces a small circle relatively rapidly. Set up in a dark room, and play with the switching speed until you can no longer distinguish individual spots/blurs as it traces the pattern on a wall. Based in my experience with a 144Hz monitor, I'm betting that if it was moving fast enough, I'd still be able to tell the difference at 500Hz, anyway. Possibly a lot higher. I'd be fascinated to get empirical results back. Especially if they proved me wrong.
- StavrosK 8y ago
  You could probably easily build a rig like that with a laser pointer and two servos, you don't need an extensive electronics background. The sample code put there would get you pretty far.
  - londons_explore 8y ago
    Servos that can move something at 500Hz are hard to come by... Galvanometers are the normal way to do that, but they are quite expensive and not a normal part of the hobby electronics repertoire.
    - StavrosK 8y ago
      You don't need it to move at 500 Hz, you can even just have it spinning around with constant speed. All you need is for it to be sufficiently fast so you can check if you notice any gaps.
    - 0db532a0 8y ago
      Gears?
lozenge 8y ago
There need not be any limit. The eye can pick up a of a single photon in the right context. It doesn't get any briefer than that.
- kiriakasis 8y ago
  That is irrelevant here, the point is how long does it take to distinguish two consecutive inputs as distinct.

by snazz 8y ago

baroffoos 8y ago

The eyes don't have a framerate. A video at 60fps looks smooth but a single black frame on a white video is visible even at much higher fps. If I move my mouse quickly in circles on a 60fpx screen it looks like I have 10 individual cursors in a ring but if I move my finger quickly in circles it looks like I have a slightly transparent ring shaped finger with no gaps in between, I can see the smooth curve of the path that my finger took which would have to be captured at an incredibly high framerate to display on a monitor.

psandersen 8y ago
A bit off topic but I've been thinking there has to be a better way of handling this at the LCD controller level here... Currently, a 60hz screen isn't perfect and pixel overdrive will be used to reduce motion blur. In effect, there are more 'unique intermediate frames' being displayed as the system tries to approximate the discrete input frames physically. The actual blur on fast-moving content on a modern screen is huge... Ignoring latency for a moment, if a controller has the previous and next frame plus motion vectors and knowledge of the precise pixel response and decay curves for the monitor... it should be possible to continuously adjust the current/voltages(?) to every pixel to better approximate what a much higher refresh rate low motion blur panel would look like on high fps content. Can't remove blur but can make motion continuous rather than a stair step. A kind of smart motion interpolation + overdrive implementation. The assumption is the higher fps the more linear the motion is frame to frame. 30 to 60fps interpolation should have more noticeable abnormalities than 120 to 1000hz.
- londons_explore 8y ago
  I'd like to see a demo of this... I doubt one could make it work for computer graphics (since motion vectors aren't easily accessible), but when displaying video the results could be good, although users seem to dislike content with interpolated generated frames, and perhaps your proposed tech could get a similar response.
  - psandersen 8y ago
    Arguably computer graphics are the best candidate since many engines already have a velocity buffer for effects like temporal anti-aliasing and motion blur... would need API integration though. My hunch is motion interpolation is preferred at high fps. E.g. a high action scene at 30 fps will need a lot more information to be filled in and has likely already been mastered with the target frame rate in mind (camera shutter speed etc). But 120hz or more content will have very little motion between frames, and this motion will be far more linear (e.g. a finger might move 1cm between frames, but doesn't bend so less motion artefacts). So 120hz content upscaled to 960hz+ would be much closer to native 960hz content and preferable to displaying at the original 120hz. A logical implementation would be VR headsets with a built-in DSP.
- pjc50 8y ago
  The individual pixels are only row-column addressable, unfortunately.
- tk75x 8y ago
  https://www.svp-team.com/wiki/Main_Page https://www.svp-team.com/wiki/Main_Page This came to mind

chowells 8y ago

I have an idea to test, but I don't have the kind of electronics background to construct the necessary rig affordably. Or possibly to identify it if one exists already. Here's my thought: connect a laser to a high frequency switch, similar to what you'd find in a PWM controller. Then rig the laser to move such that the beam traces a small circle relatively rapidly. Set up in a dark room, and play with the switching speed until you can no longer distinguish individual spots/blurs as it traces the pattern on a wall. Based in my experience with a 144Hz monitor, I'm betting that if it was moving fast enough, I'd still be able to tell the difference at 500Hz, anyway. Possibly a lot higher. I'd be fascinated to get empirical results back. Especially if they proved me wrong.

StavrosK 8y ago
You could probably easily build a rig like that with a laser pointer and two servos, you don't need an extensive electronics background. The sample code put there would get you pretty far.
- londons_explore 8y ago
  Servos that can move something at 500Hz are hard to come by... Galvanometers are the normal way to do that, but they are quite expensive and not a normal part of the hobby electronics repertoire.
  - StavrosK 8y ago
    You don't need it to move at 500 Hz, you can even just have it spinning around with constant speed. All you need is for it to be sufficiently fast so you can check if you notice any gaps.
  - 0db532a0 8y ago
    Gears?

lozenge 8y ago

There need not be any limit. The eye can pick up a of a single photon in the right context. It doesn't get any briefer than that.

kiriakasis 8y ago
That is irrelevant here, the point is how long does it take to distinguish two consecutive inputs as distinct.