White Balance And Shading Correction - Schäfter+Kirchhoff SK6288GKOC-L Instruction Manual

White Balance and Shading Correction

Shading Correction compensates for non-uniform illumination, lens vignetting as well as any differences in pixel
sensitivity. The signal from a white homogeneous background is obtained and used as a reference to correct each
pixel of the sensor with an individual factor, scaled up to the intensity maximum (255 at 8-bit resolution and 4095 at
12-bit) to provide a flat signal. Shading correction with a balanced RGB sensitivity ensures a natural color reading.
The reference signal is stored in the Shading Correction Memory (SCM) of the camera and subsequent scans are
normalized using the scale factors from this white reference.
Step 1: Gain Adjustment
• Use a homogeneous white object, e.g. a white sheet of paper, to acquire RGB line signals.
Color line signal with separated RGB curves
• Open the "Gain/Offset Control" dialog. Use the gain sliders to adjust all three curves to the same level. Some
camera models provide two gain/offset channels - thus two sliders - per color.
"Gain/Offset Control" Dialog
Color line signal with RGB curves after Gain Adjustment
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SK6288GKOC-L Instruction Manual (06.2015)
3 Camera Control and Performing a Scan
Schäfter + Kirchhoff GmbH • Hamburg
© 2015