VG6640 datasheet(86/126 Pages) STMICROELECTRONICS

86 / 126 page

Test pattern generation

VG6640, VD6640

86/126

DocID023597 Rev 11

8.1.1

100% color bars pattern mode

In the ‘100% color bar’ test pattern mode, all pixel data is replaced with a Bayer version of

an 8-bar color bar pattern. In each bar all pixels are either 0% or 100% full scale.

Figure 27. 100% color bars

8.1.2

‘Fade to gray’ color bar mode

In the ‘fade to gray’ color bar test pattern mode, all pixel data is replaced with a color bar that

fades vertically from 100% color bars to mid gray. The ‘fade to gray’ color bar pattern is

designed to exercise more of the color space than 100% bars. Figure 28gives an indication

of the pattern (although the pattern is generated as Bayer data).

Figure 28. Fade to gray’ color bars

The pattern is made up of eight vertical bars that fade vertically from one of the 100% color

bar colors towards a mid-gray at the bottom. The bars follow the same order as standard

color bars. Each of the bars is sub-divided vertically into a left hand side that contains a

smooth gradient and a right hand side that contains a quantized version.

The aim of the quantized portion is to offer areas of flat-field Bayer data that should be large

enough to result in known data values even after demosiac (independently of the demosiac

algorithm). To ensure maximum dynamic range in the quantized data, the LSBs of the

quantized data are generated by copying the MSBs of the unquantized data (rather than

forcing them to 0). The pattern repeats after 256 lines.

VG6640 Datasheet(PDF) 86 Page - STMicroelectronics