# Gamma correction

Discussion in 'Electronic Design' started by [email protected], Jan 25, 2009.

1. ### Guest

I have this small lcd display
http://www.sharpsme.com/Page.aspx/europe/en/part/LQ043T3DX02/
wrong)....In lcd display gamma correction is performed by lcd drive
circuit: it applies an ac voltage in lc cell to obtain desidered
Transmittivity/voltage characteristics (transmittivity/voltage without
correction is a sigmoidal fuction). How can i know corrected function?
is it linear or power-law (as crt)?
Another question:
backlight_luminance*transmittivity=output_luminance. If transmittivity
is a linear function, when is more useful a contrast change respect to
a backlight_luminance change? Backlight_luminance change is more power
saving, so i can obtain the same output result with less power...or
not?
Thanks for the help (i'm new in this field, so excuse me for the
questions)

2. ### Guest

I don't undestand: the output effect should't be the same?

3. ### Jasen BettsGuest

do a linear ramp and a black & white Burkes dither of a linear ramp adjacent in the same
image adjust gamma until they agree.

4. ### qrkGuest

There are many web sites with gamma charts. This site gives info on
gamma and has a few charts about midway through the article. Look
around enough and you'll find different types of charts.
http://www.normankoren.com/makingfineprints1A.html

If you need to adjust gamma on your monitor, you'll probably need to
do it though the graphics card driver. I'm finding that some LCD
panels don't do brightness and contrast properly. Most modern graphics

5. ### Guest

Thanks everybody for the help....
Ok, i understand now, but i'm not able to apply this answer in this
function
http://img401.imageshack.us/img401/1339/functionrq3.jpg
with b[0;1] =backlight factor=luminance/maximum luminance
If contrast changes, dt(x)/dx changes....what happens if backlight