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.
TV backlight compensation (2020)
21–30 of 127 posts
Re: TV backlight compensation (2020)
#22Earlier quoted context omitted.
OLED TV's try to prevent burn in, I am not sure it can compensate burn in
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.
Re: TV backlight compensation (2020)
#23Earlier quoted context omitted.
OLED TV's try to prevent burn in, I am not sure it can compensate burn in
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...
Burn-in is probably somewhat computable as a function of brightness, time, and temperature or so. So it can be compensated physically (burn out the other pixels... you don't want to be in the room, it's going to be annoyingly bright) or digitally by adjusting the signal.
Re: TV backlight compensation (2020)
#24This 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), and the shift is non-uniform due to potato-quality lighting.
Glad I caught this post, I hope the solution can contribute to my problem (although I do not have a way to obtain a fixed ground truth — lighting will change for each picture.)
Re: TV backlight compensation (2020)
#25[deleted]
Re: TV backlight compensation (2020)
#26Earlier quoted context omitted.
OLED TV's try to prevent burn in, I am not sure it can compensate burn in
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)
Re: TV backlight compensation (2020)
#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 monitors without glaring QA problems. No matter how much you spend they sell you shit.
Re: TV backlight compensation (2020)
#28Gnome (Ubuntu, Linux) allows a custom shader to be applied to the whole desktop, including fullscreen apps.
Here is an up to date fork with some example shaders: https://github.com/Hello1024/gse-shader
I use it to make sure a 'sensitive' pixel on my screen never turns on (it's a row of pixels which, if the difference between it and the pixels to the side have more than a certain difference in brightness, the whole screen fails - presumably due to a power supply fault in the column driver circuitry).
Re: TV backlight compensation (2020)
#29This 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)…
A common alternative solution in this case would be to use an adaptive thresholding technique such as Otsu’s method.
Re: TV backlight compensation (2020)
#30Earlier quoted context omitted.
OLED TV's try to prevent burn in, I am not sure it can compensate burn in
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...
[deleted]