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9. Image
Black level
Δ
G
ΔΒ
Δ
R
R
G
B
Image 9-30
One can conclude here that a good color tracking can only be met by using three previously (input) balanced
color signals
Analog Digital Conversion
The analog color signals must pass through an Analog/Digital conversion circuit prior to any digital processing in the PMP.
A typical ADC transforms the analog value into an 8 bit coded digital signal.
The graphic shows that when converting a signal containing a DC offset component the range of the converter is not optimally used.
Black level
Δ
R
ADC
0
255
i1 : superfluous information
i2 : video information
Image 9-31
One can conclude here that a good data conversion can only be met by using three previously (input) balanced
color signals
The objective of input balancing
The objective in input balancing is to “set” the same black level and the same white level for the three colors of a particular input
source.
Black level setting : brightness
White level setting : contrast
The same absolute black and white level for the three colors allows the same reference for Brightness and Contrast control of the
picture !
These two references also set the range in which the ADC will work for that particular source (this explains also why each input
balance setting is linked to a particular source and thus saved in the image
fi
le).
9.3.7.2
Adjusting the input balance
How can it be done ?
To balance the three color signals of a particular source there are conditions; in fact we must know the black and the white level of
the source i.e. :
1.
The source in question must be able to generate a white signal, ideally a 100% white (background) full screen pattern
2.
The source in question must be able to generate a black signal, ideally a 100% black (background) full screen pattern
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R5905158 HDF SERIES 16/06/2015
Summary of Contents for HDF W series
Page 4: ......
Page 10: ...Table of contents 6 R5905158 HDF SERIES 16 06 2015...
Page 44: ...3 Physical installation 40 R5905158 HDF SERIES 16 06 2015...
Page 52: ...4 Input Communication 48 R5905158 HDF SERIES 16 06 2015...
Page 64: ...5 Getting started 60 R5905158 HDF SERIES 16 06 2015...
Page 70: ...6 Quick set up adjustment 66 R5905158 HDF SERIES 16 06 2015...
Page 131: ...9 Image Image 9 103 Time out input R5905158 HDF SERIES 16 06 2015 127...
Page 132: ...9 Image 128 R5905158 HDF SERIES 16 06 2015...
Page 156: ...11 Lamp Image 11 30 Current light output 152 R5905158 HDF SERIES 16 06 2015...
Page 278: ...15 Maintenance 274 R5905158 HDF SERIES 16 06 2015...
Page 304: ...C Standard source files 300 R5905158 HDF SERIES 16 06 2015...
Page 308: ...D DMX chart 304 R5905158 HDF SERIES 16 06 2015...
Page 314: ...E Stacking HDF series projectors 310 R5905158 HDF SERIES 16 06 2015...
Page 318: ...F Environmental information 314 R5905158 HDF SERIES 16 06 2015...