Blur Busters Forums

Who you gonna call? The Blur Busters! For Everything Better Than 60Hz™ Skip to content

Strobing with active shutter glasses?

Advanced display talk, display hackers, advanced game programmers, scientists, display researchers, display manufacturers, vision researchers. The masters on Blur Busters.

Strobing with active shutter glasses?

Postby Lifestop » 04 Oct 2019, 14:06

This is probably a dumb question, but could strobing (sort of) be accomplished through the use of active shutter glasses (3d television) synced up with a pc display? Instead of blocking vision in one eye at a time for 3d, why not block both eyes for brief intervals to accomplish something similar to ulmb?

I'm not tech savy, but just a little curious after reading about how active shutter glasses work.
Lifestop
 
Posts: 3
Joined: 16 Feb 2019, 12:17

Re: Strobing with active shutter glasses?

Postby RealNC » 04 Oct 2019, 14:28

Doable, but why? Doing the strobing on the display itself gets rid of the need for glasses, so it's way more practical.
TwitterSteamGitHubStack Overflow
The views and opinions expressed in my posts are my own and do not necessarily reflect the official policy or position of Blur Busters.
User avatar
RealNC
 
Posts: 2800
Joined: 24 Dec 2013, 18:32

Re: Strobing with active shutter glasses?

Postby Chief Blur Buster » 04 Oct 2019, 18:37

Lifestop wrote:This is probably a dumb question, but could strobing (sort of) be accomplished through the use of active shutter glasses (3d television) synced up with a pc display? Instead of blocking vision in one eye at a time for 3d, why not block both eyes for brief intervals to accomplish something similar to ulmb?

I'm not tech savy, but just a little curious after reading about how active shutter glasses work.

I'm answering in a "What if?" scientific matter of interest, rather than practicality.
Usually, when this question is asked, the original poster has a scientific curiousity, so here goes:

Short Answer: Yes

See old thread

Long Answer: It's yes, but with some tricky gotchas

1. You still need a fast display where the GtG is mostly complete in VBI between refresh cycles, see high speed videos http://www.blurbusters.com/scanout

2. You need fast GtG in the shutter. LCD shutter glasses take time to open and close.

3. Synchronization with display refreshes. That can be challenging.

It also even works with mechanical wheels with holes in them. Running http://www.testufo.com/photo on a standard LCD, putting a desk fan in front of monitor -- shows some erratic motion blur reduction behaviours too (unsynchronized strobing). And old 1920s 3D movie experiments used mechanically-strobed 3D glasses:

Film projector strobing shutters (can be homebuilt/jerryrigged with home projector to reduce blur)
Image

Mechanically strobed 3D glasses, circa 1920s experiment
Image

...........

An Ardino + motor can spin a wheel in front of an LCD/LCoS projector and successfully do ULMB with a projector. Don't do it with DLP because of its temporally-generated color, but it would work with LCD/LCoS projector technology. Two 5% slice removed from opposite edges of a wheel (need to keep it weight-balanced), spun 30 times a second for 60Hz (60 strobes) or spun 60 times a second for 120Hz (120 strobes), attached to a motor that is spun by an Arduino in sync to a VSYNC... and you get 90% motion blur reduction on an LCD/LCoS projector! (Though, with a 90% light loss).

If no VSYNC feed, have accurate analog knob for speed in 0.001 Hz increments, so you can do manual genlock the strobe by slewing the rolling artifacts until they were between refresh cycles (visual strobe-in-VSYNC calibration exactly much like how I use Blur Busters Strobe Utility on an XL2720Z). Might be able keep manual drift-readjustments to once every few minutes if your adjustments are fine enough and you eyeball a good motion-test-pattern. You could also use a USB-bus VSYNC feed (from a system tray app monitoring .InVBlank and transmitting those to the Arduino) and use some "noisy-VSYNC" filtering logic (similiar to the one ad8e provided for his C++ equivalent of Tearline Jedi) to filter the USB ping jitter to get the original VSYNC tick-tock. Stick to Arduinos with <1ms USB lag though.

Arduino-driven spinning-mechanical-wheel strobing works excellently with lowering persistence of sample-and-hold LCD/LCoS projectors. I've talked about this years ago too.

If anyone does a spinning-disc persistence-lowering device for LCD/LCoS device, please post here. It's a fun cheap Arduino experiment.

Tips for external strobing devices (glasses, mechanical):
- Manual genlock mode (need to be able to speedup/slowdown in tiny increments with an analog knob)
- VSYNC trigger genlock mode (listen to an external VSYNC signal on a GPIO pin)
- Phase offset adjustment (flash position relative to VSYNC position)
- Length variable (slit size on spinning wheel, or shutter length for active shutters)
- For rolling shutters, roll the shutter downwards, in sync with rolling scan, for best results. Most LCD/LCoS microdisplays use a downward sweep, www.blurbusters.com/scanout
Head of Blur Busters - BlurBusters.com | TestUFO.com | Follow @BlurBusters on Twitter

       To support Blur Busters:
       • Official List of Best Gaming Monitors
       • List of G-SYNC Monitors
       • List of FreeSync Monitors
       • List of Ultrawide Monitors
User avatar
Chief Blur Buster
Site Admin
 
Posts: 6409
Joined: 05 Dec 2013, 15:44

Re: Strobing with active shutter glasses?

Postby masterotaku » 09 Oct 2019, 03:57

I have done a bunch of experiments like this. There is a program that can change the timings of the Nvidia 3D Vision glasses (https://www.nvidia.com/en-us/geforce/fo ... tweak-you/). You can see the effects after just alt+tabbing into the game again.

Things I did (all for playing in 3D except the last point in the list):
- 80Hz 3D Vision mode with perfect timings for non ULMB mode and with reduced glasses "on" time (between 3 and 4 ms). The image quality was great (zero crosstalk and excellent overdrive) but the funny thing is that you could see the high monitor brightness hitting your face while having a dimmer (with lower motion blur) image through the glasses.
- Same but with ULMB enabled (it has more 3D crosstalk because of worse overdrive, but lower motion blur) and same for other refresh rates (although 144Hz was bad. TN is too slow).
- Reduced glasses "on" time for 120Hz (between 1 and 1.5 ms) to reduce the mandatory ~2.5ms of Lightboost of my monitor. The drawback is that the glasses aren't as fast as I needed and the sides showed crosstalk. Same for other refresh rates.
- In some games or "emulator games" (like the first two Mega Man Legacy Collection) I have added the feature to make the right eye black to effectively make a black frame insertion feature for 60fps capped games while not wearing the glasses.

I also have to add: 3D Vision is awesome and it shouldn't have been so underrated and ignored :p (I play/fix games with it every single day).
CPU: Intel Core i7 7700K @ 4.9GHz
GPU: Gainward Phoenix 1080 GLH
RAM: GSkill Ripjaws Z 3866MHz CL19
Motherboard: Gigabyte Gaming M5 Z270
Monitor: Asus PG278QR
User avatar
masterotaku
 
Posts: 436
Joined: 20 Dec 2013, 04:01


Return to Area 51: Display Science, Research & Engineering

Who is online

Users browsing this forum: No registered users and 3 guests