John2 wrote: ↑25 Feb 2021, 12:56
Man I swear out of all the subject I have ever tried to learn in my life this subject here of diplay motion blur is one of the hardest I have ever tried to wrap my head around (apart from math of course I'd say math was the harderst), the more I look into it the more questions I keep having.
Display science is much easier to understand when you have a 240Hz display because it allows you to
see for yourself (60 vs 120 vs 240) of various artifacts by running specific TestUFO tests. Once you realize the behaviour, it becomes easy to mentally extrapolate.
Do you have any access to 120Hz or 240Hz display, with or without an optional strobing mode?
John2 wrote: ↑25 Feb 2021, 12:56
So about this mouse stepping effect, I definitely never noticed it but after it was pointed out to me thanks to blurbusters I did what you said and stared at a fixed point on the screen and moved the mouse about and I guess I can barely see the stepping effect just barely. But why oh why does the stepping effect only happen to just the mouse?
That's actually an assumption that is a myth -- you should read
The Stroboscopic Effect of Finite Frame Rates.
If you read the
Stroboscopics article, you'll realize the effect occurs with all high-contrast motion, not just with the mouse arrow.
Testing The Stroboscopic Effect in a Game
- Load a game with high contrast objects
......Cyberpunk 2077 bright neon in black background
......Vertical dark-vs-bright boundaries during horizontal pannings.
.
- Go to some place in FPS game with high contrast (superbright stuff next to superdark stuff like neons/streetlamps/etc) (or a bright sunlit-vs-dark shadow vertical wall edge in CS:GO)
.
- Stationary-gaze at crosshairs while turning left/right. Force your eyes to stare ONLY at the crosshairs permanently for the duration of the test. Turn left/right very fast by swiping mouse left and right.
.
- You will see the mousedropping effect whenever your eyes are at a different motion vector than the game's motion. For example, stationary gaze at crosshairs while background scrolls past.
Questions:
1. Do you have a recent VR headset? (any OLED or new 2020 LCD)
2. Do you have a 240Hz display?
3. Do you have a small, medium, and huge display that your computer can connect to?
4. Can any of your displays do a high-quality strobe mode?
If you don't have 1/2/3, it becomes more difficult to teach certain elements of display science, because the "
aha, 2+2=4" easy teachable moments is seeing-for-yourself "how refresh rate doubling" scales (60Hz vs 120Hz vs 240Hz). Swich to 60 Hz, do a TestUFO, switch to 120Hz, do a TestUFO, switch to 240Hz, do a TestUFO, then it becomes easy to extrapolate what happens at 480Hz or 960Hz (and it's also experimentally verified that the guesses are correct, in the laboratory high-Hz displays) --
It is also precisely why 60fps YouTube videos are almost impossible to correctly teach some display-concepts. I need 120fps HFR (or ideally 240fps HFR) to properly teach some Blur Busters concepts in a proper quicker ELI5 format. When 240Hz iPhones becomes widespread, I can broadcast 240fps HFR to them using a special video player (YouTube doesn't support 240fps), so we'll see how the world improves in high-Hz education.
Once I show off a real 240Hz display to a classroom, some of the motion blur concepts become simple high school mathematics. It is actually hard to grasp head around it if you've been only staring at 60Hz LCDs or low-quality 120Hz LCDs (where GtG is too big to make 120Hz exactly half the motion blur of 60Hz). I also do paid classroom services from time to time.
John2 wrote: ↑25 Feb 2021, 12:56
Shouldn't it happen to any single object on the screen that moves fast such as a car or just when the camera pans really fast, I mean you say the stepping effect happens when the cursor is moved really fast but by that logic the stepping effect should to be happening to anything that moves fast, and so one of the things I did was start scrolling the webpage up and down really fast while I looked at a fixed point and could not notice a stepping effect on anything on the screen
Your executed very limited scientific experiment test variables.
- Also, most people don't pay attention until they're "trained" to this effect.
- Also, not everyone can see it (i.e. not picky about it; some people are more sensitive to it)
- Or there might be motion medical issues such as Conjugate gaze palsy, or Akinetopsia, or whatever.
For a beginner tester doing this:
To Amplify Experimential Observations With Web Browser:
- You need a longer observation time of multiple seconds.
- Try a super long webpage with 100 pageful of scrolling for a longer scroll observation.
- Try a webpage without images, to prevent webpage scroll stuttering.
- Try a lower refresh rate to begin with, like 60 Hz or 75 Hz (lower Hz = easier to see)
- Try a bigger display like desktop LCD, not a phone or tablet (bigger FOV = easier to see)
- Make sure your browser is GPU accelerated (don't use a 10-year-old laptop) for smooth scrolling
- Try automatic scrolling so you don't have to touch the mouse (let go of mouse) after you begin scrolling. This decouples eye-hand coordination-effect that can distract some people's brain from seeing the artifact.
Steps To See Stroboscopic Text Effect In Browser Scroll
- View this big web page www.xmpp.org/extensions/xep-0301.html (an old spec I made)
It's about 100 pages tall with no images, perfect for this educational exercise.
.
- Click the middle mouse button (not scrollbar) to switch your mouse into smooth autoscroll mode.
.
- Your mouse cursor should look like this on both PC and Mac
- autoscroll.png (2.96 KiB) Viewed 15302 times
.
- Now move your mouse downwards. You'll see the page automatically scroll superfast smoothly.
.
- Stare at center of webpage while it scrolls very fast for a few seconds.
.
- You should see stroboscopic text effect.
.
- If you still can't see it, repeat steps 1-6 with faster autoscroll speed.
You can autoscroll faster by moving mouse further away from middle click location to autoscroll faster.
You can reverse scroll by moving mouse above middle-click location.. Go back-and-fourth at different speeds.
Additionally, try Dark Mode temporarily. Stroboscopic text is easier to see in dark mode. Windows Search Box->"Dark"
- dark-mode.png (3.52 KiB) Viewed 15302 times
This is why effects are often easier to see on bigger displays at higher resolutions, thanks to
Vicious Cycle Effect. What you sometimes don't see on a small phone can be amplified on a big display.
That is why maybe ~240Hz to ~480Hz-ish (random numbers, don't take my word) might be a final frontier for phones, while ~10,000Hz-ish (random number, don't take my word) might be a final frontier for 180-degree FOV VR headsets (IMAX screen strapped to your face). The bigger, the higher refresh rate is needed to retina-it-out. The wider-FOV, the higher the refresh rate is needed to retina-it-out. (distant tiny TV versus jumbotron VR strapped to your eyes). Etc. etc.
Should be obvious/easy to understand once you read the other reply -- hopefully, especially if you have a 240Hz display to run the educational animations to properly test the versus-animations to help your brain extrapolate the line beyond 60-120-240 (because it becomes obvious what happens at 480Hz or 960Hz). Once you've seen something at 60Hz then 120Hz then 240Hz, it becomes super-easy to guess what happens at 480Hz for certain motion tests. That's why my TestUFO PowerPoints (during travel) brings my 240Hz laptop for teaching purposes.
The bigger the FOV, the higher the refresh rate you need. This
post is another good explanation why higher resolutions and bigger displays amplify the need for higher refresh rates.
Conclusion:
Eye tracking = eye movement EQUAL display motion speed = persistence blur (equalling frame visibility time)
Eye stationary = eye movement UNEQUAL display motion speed = stroboscopic effect