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TV backlight compensation (2020)

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Re: TV backlight compensation (2020)

#51

Post by kevingadd »

nottorp wrote: post #33
ifqwz wrote: post #27

The quality of computer monitors is appalling - after buying and returning several monitors because of quality issues, I briefly considered doing this system-wide to fix colour uniformity problems. Eventually I chose to keep my old monitor instead. It has uniformity problems as well but it doesn't cost me $1000 extra to keep. But it's a damn shame that you can't throw enough money at manufacturers to make them make m…

You talking about mainstream "gaming" monitors? I'm just a programmer and gave up on those long ago. Getting entry level monitors targeted at graphic designers now. Namely Asus ProArt and I think Dell has similar stuff? They don't have 240 Hz and sub 0.01 ms response times though, so if you're buying your hardware based on bigger numbers in specs they won't do. They're probably not that great for actual designers eit…

The first graphic design monitor I bought from Benq had a busted image processor so that you couldn't turn off the sharpening - only set it to -5% (blurry) or +5%. Eventually I complained enough that they sent me a different monitor that didn't have the problem.

I've had bad experiences with some of Dell's pro-grade monitors too. It feels like modern displays are so complex firmware and hardware wise that it's just very hard to find one that isn't defective in some way. This replacement Benq works for basic uses but its freesync is broken and it's already developed burn-in around the edges after about 1.5 years.

Re: TV backlight compensation (2020)

#52

Post by autoexec »

BoorishBears wrote: post #36
ifqwz wrote: post #27

The quality of computer monitors is appalling - after buying and returning several monitors because of quality issues, I briefly considered doing this system-wide to fix colour uniformity problems. Eventually I chose to keep my old monitor instead. It has uniformity problems as well but it doesn't cost me $1000 extra to keep. But it's a damn shame that you can't throw enough money at manufacturers to make them make m…

My XDR has been pretty flawless, and on the less exorbitantly priced end, I've had good experiences with a few business oriented IPS models (most recently the Samsung UR55). My main gripe is gaming monitors seem to be consistently the worst panels they can get their hands on. It seems like they realize gamers will put up with a lot of garbage in exchange for raw "power" and take full advantage of the fact. I'm 99% su…

If you fill your entire screen with nothing but a single solid color (try #FF6400) does it show up correctly? That is, without any gradient or areas of the screen where the color appears darker or lighter (especially around the edges or in the corners?).

I've yet to find a modern monitor that doesn't have a problem with that basic test, which is pretty disappointing considering accurately representing a single color should be easy and I've had several CRTs that could do it.

Re: TV backlight compensation (2020)

#53

Post by rzzzt »

infomax wrote: post #40

I have the same idea each time I read something about backlights; How easy would be to place a cheap LCD at the back of the main screen and mirror the same output (in horizontally inverted mode)? Technically it might require synchronizing the frame latency differences between the two devices, but would such a hack improve the perceived quality?

The cheap LCD will probably not be able to produce enough light to brighten up the main display, and if the two panels are not of equal size, you will need to add some depth to the unit and come up with a projection system to "blow up" the light map to cover the entire image.

Re: TV backlight compensation (2020)

#54

Post by agent008t »

axiolite wrote: post #5
unglaublich wrote: post #3

I wouldn't call this over-engineering. It's a reasonable solution to an actual problem.

I think the reasonable solution is: Buy a new TV. We're not talking about a jumbotron display here. A cheap new TV with proper color is likely very inexpensive.

Where is the fun in that? We are alienated enough from the stuff we consume as it is.

Re: TV backlight compensation (2020)

#55

Post by jagged-chisel »

drumdude wrote: post #21

I do this for a living. Sony digital cinema projectors use a type of LCD panel (SXRD) where the uniformity drifts over time. A special camera takes about 35 minutes to create a LUT to restore the projected image to a uniform white.

Is that 35 minutes spent collecting input, or calculating the LUT?

Re: TV backlight compensation (2020)

#56

Post by ifqwz »

autoexec wrote: post #52
BoorishBears wrote: post #36

Earlier quoted context omitted.

My XDR has been pretty flawless, and on the less exorbitantly priced end, I've had good experiences with a few business oriented IPS models (most recently the Samsung UR55). My main gripe is gaming monitors seem to be consistently the worst panels they can get their hands on. It seems like they realize gamers will put up with a lot of garbage in exchange for raw "power" and take full advantage of the fact. I'm 99% su…

If you fill your entire screen with nothing but a single solid color (try #FF6400) does it show up correctly? That is, without any gradient or areas of the screen where the color appears darker or lighter (especially around the edges or in the corners?). I've yet to find a modern monitor that doesn't have a problem with that basic test, which is pretty disappointing considering accurately representing a single color…

Most people will tell you that their monitor is flawless, then you do simple tests like that one and the monitor shows that it has severe issues and they respond "uh I never noticed, well I don't care". Which is precisely why manufacturers can get away with the shit that they sell.

Re: TV backlight compensation (2020)

#57

Post by empiricus »

orbital-decay wrote: post #26
empiricus wrote: post #20

Earlier quoted context omitted.

I don't see how the TV can compensate for the burnin without having an external picture of the screen. I have a couple of years old OLED TV, and it has burn in... The Netflix logo, the netflix animation, and subtitles are quite visible all the time now. This is despite running periodically the TV pixel refresh or however it is called...

> I don't see how the TV can compensate for the burnin without having an external picture of the screen. Build a comprehensive degradation profile of your LEDs. Keep the burn-in accumulation buffer that tracks intensity and usage amount of each subpixel. Use it in your EOTF to correct the picture. Some color-accurate monitors like Eizo are even profiled for temperature (and have a grid of temperature sensors)

sounds good in theory, but what about gradual errors accumulating after thousands of hours/millions of frames?

Re: TV backlight compensation (2020)

#58

Post by Tomte »

Rygian wrote: post #24

This is almost identical to a problem I'm trying to solve, which is to turn a potato-quality picture of a sheet of paper into a clean scan, turning whatever levels of gray conform the paper background become a uniform #ffffff white. The obvious solutions (equalizing, converting to bitmap, …) don't work because what's white in the top left (say #ccc) is wildly different from what's white in the bottom right (say #888)…

Would https://www.imagemagick.org/Usage/compose/#divide help?

Re: TV backlight compensation (2020)

#59

Post by empiricus »

serd wrote: post #22
empiricus wrote: post #20

Earlier quoted context omitted.

I don't see how the TV can compensate for the burnin without having an external picture of the screen. I have a couple of years old OLED TV, and it has burn in... The Netflix logo, the netflix animation, and subtitles are quite visible all the time now. This is despite running periodically the TV pixel refresh or however it is called...

Could you share a photo? I'd really like to see that.

https://i.postimg.cc/1Xy6V5wb/oledburn.jpg

not the greatest picture (some reflections). should have used a gray background, but I used red because this color is the most affected.

The burnin is mostly harmless, but the middle blob is very annoying; yellow parts of the image become greenish when they get to the middle of the screen.

Re: TV backlight compensation (2020)

#60

Post by xattt »

franky47 wrote: post #44
EZ-Cheeze wrote: post #41

Earlier quoted context omitted.

I'll do it when I can just tell the computer to do it - maybe 2024 It will be interesting to rewatch movies with all the faces blanked out - they're eye-magnets that prevent you from noticing other details, for example in body language

Funny how recent developments in AI have warped our comprehension of what is easy to ask to a computer vs what is hard. Obligatory related XKCD: https://xkcd.com/1425

AI is turning out to be the singularity that science fiction writers talked about. You just have no freaking idea what’s next at this point.
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