Does overdrive affect stroboscopic effects/phantom array

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yuri
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Does overdrive affect stroboscopic effects/phantom array

Post by yuri » 26 Oct 2022, 13:41

Hi everyone :)

I would like to know if overdrive Can make stroboscopic effect more visible due to a lack of overall Blur?
If yes, does ghosting can help for masking the gaps between two frames.?

The persistence is related to overdrive too?

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Re: Does overdrive affect stroboscopic effects/phantom array

Post by Chief Blur Buster » 26 Oct 2022, 19:02

yuri wrote:
26 Oct 2022, 13:41
Hi everyone :)

I would like to know if overdrive Can make stroboscopic effect more visible due to a lack of overall Blur?
Remember there are two pixel response measurements, GtG and MPRT.

Overdrive doesn't fix MPRT motion blur. It only adjusts the GtG component of motion blur.
Remember, both MPRT and GtG can add motion blur, and overdrive only adjusts the GtG component.

www.blurbusters.com/faq/lcd-motion-artifacts-101
www.blurbusters.com/faq/lcd-overdrive-artifacts
www.blurbusters.com/gtg-vs-mprt
www.blurbusters.com/stroboscopics

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yuri wrote:
26 Oct 2022, 13:41
If yes, does ghosting can help for masking the gaps between two frames.?
Not really. Overdrive has no effect on the finiteness of frame rates.
Remember, there are FOUR situations to fix stroboscopic artifacts:
  • Stationary eyes, stationary images. (staring at stationary picture)
  • Stationary eyes, moving image. (staring at crosshairs while turning)
  • Moving eyes, stationary images. (staring at moving object zooming on stationary background)
  • Moving eyes, moving images. (tracking eyes on objects while simultaneously scrolling / panning / turning)
The only way to fix all the above concurrently is infinite frame rates at infinite refresh rates.
Even 1000fps 1000Hz is not enough to fix stroboscopic effect.
More reading at Blur Busters Area 51 Research: www.blurbusters.com/area51

If you HATE stroboscopic effect, turn on GPU Motion Blur Effects in your game. For some people, GPU Motion Blur is an "Assistive Feature" or "Ergonomic Feature" when stroboscopic artifacts are the source of eyestrain / nausea. Thankfully GPU Motion Blur is less at high frame rates (e.g. 100fps 100Hz), so raise your framerate as much as you can.
yuri wrote:
26 Oct 2022, 13:41
The persistence is related to overdrive too?
Not really.

1. Persistence and phantom array effect are two different things.
2. Display motion blur (MPRT100%) can't be less than frametime or refreshtime (whichever is the biggest number) on a sample and hold display.
3. Overdrive chiefly affects GtG. Even GtG=0, there is still persistence motion blur. Zeroing-out GtG pixel response doesn't eliminate motion blur nor stroboscopics.

TL;DR: Turn on GPU Motion Blur Effect (instead of adjusting overdrive) if you hate stroboscopic effects. For some people, it is an ergonomic/assistive feature to reduce stroboscopics-related discomfort. This adds enough motion blur to eliminate stroboscopics
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

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Re: Does overdrive affect stroboscopic effects/phantom array

Post by yuri » 27 Oct 2022, 05:59

Okay i see, ive got an other question, why does we see the afterimage of the previous frames like strobocopics effect so much ?

I mean if Gtg an mprt is 0.1 ms does we still see the same stepping distance of a frame ?

If we move quickly our mouse we saw multiple cursor but why does those previous cursor doesn't disapear quickly ?
Why they stay so long at the screen ?

Does it is related to mprt or GTG?
Or it's about the scan out speed?

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Re: Does overdrive affect stroboscopic effects/phantom array

Post by yuri » 31 Oct 2022, 10:54

:?:

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Discorz
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Re: Does overdrive affect stroboscopic effects/phantom array

Post by Discorz » 31 Oct 2022, 11:44

yuri wrote:
27 Oct 2022, 05:59
I mean if Gtg an mprt is 0.1 ms does we still see the same stepping distance of a frame ?
Note that in ideal situation where we have infinite frame rate, infinite refresh rate, zero persistence and zero GtG the primary image will not be perfect sharp as you might imagined. In fact there would be no primary image because eye is not focused to passing object. The distance between frames (stepping) just thins into blur or non-existance because its so fast.

Mouse Cursor Stroboscopic Effect, Phantom Array, 1000+Hz FPS Estimate.png
Mouse Cursor Stroboscopic Effect, Phantom Array, 1000+Hz FPS Estimate.png (73.67 KiB) Viewed 1870 times
See https://www.testufo.com/mousearrow#count=4&pps=3840
This image is just an estimation, but notice how mouse cursor fades into background as frame rate and refresh rate increase. This is when gaze is fixed. Now try to eye-track the cursor and opposite happens - lowest refresh and frame rate fades into background. So we're basically stuck with either one or the other.

You can replicate something like this in real life - fix gaze into wall and wave a pencil or finger real fast. As eyes don't work by frame rate you would not see stepping but smear/blur instead. That's why GPU motion blur is recommended. It blurs the frames making the stepping appear as it thinned out, therefore closer to infinite frames.
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Re: Does overdrive affect stroboscopic effects/phantom array

Post by Chief Blur Buster » 31 Oct 2022, 23:31

Correct. Real life is equivalent to infinite frame rate.

The finite frame rate creates motion artifacts that mismatches real life. It's why retina refresh rate is extremely high if you want to whac-a-mole everything (not just plain flicker). A perfect Holodeck would require a quintuple-digit frame rate at quintuple refresh rates, to brute-force-framerate to match analog motion as closely as possible, in a way that oversamples all possible human-visible temporal effects.

Tricks such as GPU motion blur can fix stroboscopics, but you still have.... motion blur. If you hate motion blur AND stroboscopics, then it's a tough pick-poison if you're stuck with low frame rates.

GtG pixel response has no effect on the step-distance of stroboscopic stepping, but it can make smooth motion harder to see. Slower GtG will sometimes cause the "dissapearing mouse cursor problem" because LCD GtG is too slow for a 1-refresh-cycle mouse cursor to appear. That's why you had "Pointer Trails" on old laptops from the 1990s, to help make the mouse cursor even more visible. So ultra-slow GtG might make stroboscopic effect harder to see by making moving objects completely disappear (an even worse problem).
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Re: Does overdrive affect stroboscopic effects/phantom array

Post by Discorz » 02 Nov 2022, 07:42

This shorter space between frames (stepping) is why some people might find higher refresh rate more "blurry". It becomes harder to focus on target when there are multiple of them narrowly spaced next to each other, but when they are more widely spaced it is easier to focus on one (viewtopic.php?f=2&t=9025). On top of this GtG becomes much smaller proportion of refresh cycle, while at higher refresh rate it barely fits within 2-3 frames on some fast Hz LCDs.

The "disappearing mouse cursor" can be quite annoying. I should note if GtG was instant than 1kHz cursors wouldn't be as pale on given image.

--

It's interesting effect!
1. with tracking gaze infinite frames become zero blur, or zero MPRT blur
2. with stationary gaze infinite frames become blur, or MPRT blur

Its like zero and infinite are same thing, but actually opposite... same thing, different directions.
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yuri
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Re: Does overdrive affect stroboscopic effects/phantom array

Post by yuri » 28 Nov 2022, 07:45

And what about the length of the transition?
I mean, when moving the camera quickly we saw previous frame but what makes the last frame stay longer or shorter ? GtG ?

Because if the monitor have the lowest response Time than stroboscopic or Blur trail should disapear before we Saw it ?

Like if a monitor is set to, let say 10000hz On ideal monitor (no such thing exists) we should see completely continuos (analogue) movement.

But that mean a fast transition leads to a huge trail ?

Like a game with Blur enabled?

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Re: Does overdrive affect stroboscopic effects/phantom array

Post by Chief Blur Buster » 28 Nov 2022, 12:03

yuri wrote:
28 Nov 2022, 07:45
And what about the length of the transition?
I mean, when moving the camera quickly we saw previous frame but what makes the last frame stay longer or shorter ? GtG ?

Because if the monitor have the lowest response Time than stroboscopic or Blur trail should disapear before we Saw it ?

Like if a monitor is set to, let say 10000hz On ideal monitor (no such thing exists) we should see completely continuos (analogue) movement.

But that mean a fast transition leads to a huge trail ?

Like a game with Blur enabled?
Stroboscopic is based on positions.

GtG slow/fast does not change pixel positions, so stroboscopic count is unaffected by GtG fastness/slowness.

However, the trail intensity can change, can become longer/shorter. For example how strongly/dimly those duplicate images show up (but positions of duplicate images are unchanged). This may lead to a perception of more/fewer counts, if the trail seems longer. But a longer trail with dimmer images. However, the positions of the images are unchanged and the stroboscopic stepping distance is unchanged.
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Re: Does overdrive affect stroboscopic effects/phantom array

Post by yuri » 28 Nov 2022, 15:32

So the only thing that count is the refresh rate on sample and hold? ( About the stepping distance)

That mean OLED can in theory reduce the perception of a trail due to fast camera mouvement ? ( Not the stepping distance)

To reduce trail/previous frame perception, what is the value needed, to make the intensity of a trail invisible ?

So the response time of a monitor is the only thing that can reduce the perception of previous frame or trails intensity ?

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