MSWU-81E 07/08/2013
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8.Image
Black level setting : brightness
White level setting : contrast
The same absolute black and white level for the th ree colors allows the same reference for Brightness an d Contrast control of
the picture !
These two references also set the range in which the A DC will work for that particular source (this exp lains also why each
input balance setting is linked to a particu lar source and thus saved in the image file).
Adjusting the input balance
To balance the three color signals of a particular so urce there are conditions; in fact we must know the blac k and the white
level of the source i.e. :
1. The source in question must be able to generate a wh ite signal, ideally a 100% white (background) full screen p attern
2. The source in question must be able to generate a black si gnal, ideally a 100% black (background) full screen p attern
A B
White balance : In the projector, we will set the contrast for each col or until we get a 100% light output picture when
projecting a 100% white image (image A)
Black balance : In the projector, we will set the brightne ss for each color until we get a 0% light output picture wh en
projecting a 100% black image (image B).
The changeover from min to max is indicated by the apparition of bright spots also called “digital nois e”
An alternative to a full screen White/black pattern is the standard gray scale pattern, the white bar will b e
used for white balance and the black bar for black b alance.
Offset
This refers to the control of color imbalance in the darker areas of th e projected image.It is recommended that you use a n
external test image with many areas of dark and gray col ors (i.e. an image of 30IRE-window). If you notice minimal amount
of red, green or blue in the gray areas, adjust the offs et of the corresponding color accordingly.This function w ill shift the
entire color spectrum for the whole image a nd change its brightness.
Gain
This refers to the control of color imbalance in the brighter a reas of the projected image.It is recommended that you us e an
external test image with many areas of white (i.e. an image of 80I RE-window). If you notice minimal amount of red, green or
blue in the gray areas, lower the gain of the correspondin g color accordingly.This function is used to increase or decreas e the
range of color input for the entire image.
Generally speaking, as gain increases, the cont rast of the image will become lower.By increasing the of fset, the image
brightness will become lower.