Black Level Correction - Ricoh B156 Service Manual

Black Level Correction

• Improves image reproduction for high-density areas.
• Reads the black video level at black elements on the CCD. These pixels are
masked off, and should produce a pure black signal.
• This is subtracted from the value of each pixel.
• Calculated for each scan line.
• Corrects the image data for any changes in black level with time, as the machine
scans down the page.
VPU Test Mode
To make sure the scanner VPU control is functioning, output the VPU test pattern
with SP4-907 (for more details, see chapter 4, "Troubleshooting").
SM
CÓPIA NÃO CONTROLADA
6-25
CÓPIA NÃO CONTROLADA
IMAGE PROCESSING
B156/B200