4 ms·

There's got to be something else going on there. 280 frames/sec is about 3.5 ms/frame. Signals don't even leave the retina that fast, let alone propagate to br

There's got to be something else going on there. 280 frames/sec is about 3.5 ms/frame. Signals don't even leave the retina that fast, let alone propagate to brain areas linked to perception and action. Perhaps the higher frame rate makes the motion smoother, which allows the pilot to estimate and extrapolate an objects' motion more accurately, or something like that.

wtallis 9y ago
Smooth motion is definitely a big factor. Just look at things in terms of how fast something on screen (eg. the cursor) is moving in terms of pixels per frame. Moving a cursor horizontally across a 4k display in a relatively slow one second is 64 pixels per frame at 60Hz, which is significantly wider than the cursor itself. At 144Hz it's about 26 pixels per frame, and at 280Hz it would be about 14 pixels per frame. Even if you have a low-persistence display, you need to have a pretty high refresh rate to draw smooth motion. Hardly anything needs to be animated all the way down at 1 pixel per frame, but hardly anything currently comes at all close to that ideal strobe-free smoothness.
GuyWIthLag 9y ago
Actually, human eyes don't have a "frame rate" per se, or if you want there are different frame rates depending on the feature - and how far removed it is from the retina. Essentially, the retina itself can detect >300hz, then there's a bunch of processing as you go back the optic nerve that causes that number to drop for higher-level features.
- mattkrause 9y ago
  Any chance you have a source for that? I'm legitimately curious, since I've never heard anything like that.
hvidgaard 9y ago
The visual system do not work in frames (well, on a fundamental level I supose it does, with the indivitual photons and nerve impulses being the smallest unit, but that is not a limit in practice). The information the retina captures is streamed continuesly to the brain, so higher FPS provides a higher temporal resolution for the visual experience. I don't think a fighter pilot inheriently react faster because of the resolution, but he is trained to detect motion in his peripheral vision. Perhaps he notice the smooth motion more than people who rarely train that part of their visual system. It would be interested to see how a trained and experience hunter would compare, as they often use peripheral vision as well.
- mattkrause 9y ago
  My point was that 3.5ms frames are close to that limit. The nervous system is pretty slow. Each action potential takes about a millisecond, and is followed a refractory period of another 1-2 milliseconds or so. This limits the speed of transmission in the nervous system generally. The visual system, specifically, is even slower. There's a fairly complicated electrochemical cascade that turns photons into electrical impulses in rods and cones, and it's not fast. Drum (1982) describes several attempts at measuring the latencies of cones. The exact value depends on several factors like adaption levels and the visual stimuli, but they're all in the tens of milliseconds.
  - hvidgaard 9y ago
    I have no doubt there is a latency, but I was trying to say that the stream of information is not discrete. The stream is continues, so higher framerate means that more information will flow to the brain because the temporal resolution is higher. Are you saying that the rods and cones only "sample" every so often?
    - mattkrause 9y ago
      No, in that there is not a master clock, shutter, or anything like that that separates the visual input into discrete frames. Yes, in that phototransduction is a sluggish chemical process. The impulse-response functions of photoreceptors are pretty well-known (e.g, Figure 1 here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1189952/?page=5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1189952/?page=5). The tiny square wave at the bottom is the visual stimulation; the other traces are the responses of individual photoreceptors. Figure 4 of the paper (p. 689) shows the response to a pair of flashes. In the bottom-most trace, you can see that the photoreceptor "misses" the second visual stimulus because the responses evoked by the first and second stimuli overlap in time and interfere. I'd say that the visual system does get a continuous stream of inputs, but its output is low-pass filtered (and clipped, rectified, etc) so that faster inputs are not always reflected in its output.
      - 9y ago

wtallis 9y ago

Smooth motion is definitely a big factor. Just look at things in terms of how fast something on screen (eg. the cursor) is moving in terms of pixels per frame. Moving a cursor horizontally across a 4k display in a relatively slow one second is 64 pixels per frame at 60Hz, which is significantly wider than the cursor itself. At 144Hz it's about 26 pixels per frame, and at 280Hz it would be about 14 pixels per frame. Even if you have a low-persistence display, you need to have a pretty high refresh rate to draw smooth motion. Hardly anything needs to be animated all the way down at 1 pixel per frame, but hardly anything currently comes at all close to that ideal strobe-free smoothness.

GuyWIthLag 9y ago

Actually, human eyes don't have a "frame rate" per se, or if you want there are different frame rates depending on the feature - and how far removed it is from the retina. Essentially, the retina itself can detect >300hz, then there's a bunch of processing as you go back the optic nerve that causes that number to drop for higher-level features.

mattkrause 9y ago
Any chance you have a source for that? I'm legitimately curious, since I've never heard anything like that.

hvidgaard 9y ago

The visual system do not work in frames (well, on a fundamental level I supose it does, with the indivitual photons and nerve impulses being the smallest unit, but that is not a limit in practice). The information the retina captures is streamed continuesly to the brain, so higher FPS provides a higher temporal resolution for the visual experience. I don't think a fighter pilot inheriently react faster because of the resolution, but he is trained to detect motion in his peripheral vision. Perhaps he notice the smooth motion more than people who rarely train that part of their visual system. It would be interested to see how a trained and experience hunter would compare, as they often use peripheral vision as well.

mattkrause 9y ago
My point was that 3.5ms frames are close to that limit. The nervous system is pretty slow. Each action potential takes about a millisecond, and is followed a refractory period of another 1-2 milliseconds or so. This limits the speed of transmission in the nervous system generally. The visual system, specifically, is even slower. There's a fairly complicated electrochemical cascade that turns photons into electrical impulses in rods and cones, and it's not fast. Drum (1982) describes several attempts at measuring the latencies of cones. The exact value depends on several factors like adaption levels and the visual stimuli, but they're all in the tens of milliseconds.
- hvidgaard 9y ago
  I have no doubt there is a latency, but I was trying to say that the stream of information is not discrete. The stream is continues, so higher framerate means that more information will flow to the brain because the temporal resolution is higher. Are you saying that the rods and cones only "sample" every so often?
  - mattkrause 9y ago
    No, in that there is not a master clock, shutter, or anything like that that separates the visual input into discrete frames. Yes, in that phototransduction is a sluggish chemical process. The impulse-response functions of photoreceptors are pretty well-known (e.g, Figure 1 here: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1189952/?page=5 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1189952/?page=5). The tiny square wave at the bottom is the visual stimulation; the other traces are the responses of individual photoreceptors. Figure 4 of the paper (p. 689) shows the response to a pair of flashes. In the bottom-most trace, you can see that the photoreceptor "misses" the second visual stimulus because the responses evoked by the first and second stimuli overlap in time and interfere. I'd say that the visual system does get a continuous stream of inputs, but its output is low-pass filtered (and clipped, rectified, etc) so that faster inputs are not always reflected in its output.
    - 9y ago