ABL electronic Scamax 5000 - Manual (Page 10)

DpuScan
Scamax 2600 / 5000 Scanner Options
DTplus Threshold (two-dimensional)
If the scanner has the DTplus board (optional), several image lines can be considered for the
black/white decision. As with the Automatic Threshold, not only the value itself, but also
deviations in its surroundings are considered.
The setting for brightness serves as the threshold for areas, and the setting for Contrast as the
sensitivity level for graylevel differences.
Recommended Values: Brightness = 165; Contrast = 12
Contrast
The contrast value defines the sensitivity for graylevel changes at neighboring pixels that will lead to
an interpretation of black or white. The lower the contrast, the higher the sensitivity level of the
scanner for graylevel changes.
For the automatic threshold, the Contrast can be set in 8 levels of sensitivity
Recommended Value = 4
If the device features a DTplus board, the two-dimensional DTplus threshold can also be used. Here,
127 theoretical sensitivity levels are available, but sensible settings are in the range between 5 and 25
Recommended Value = 12
Brightness
The brightness can be freely selected between values of 0 to 255. This represents the 256 graylevels
that the camera can capture. Sensible settings lie, as per the threshold method, between the values
of 120 and 180.
With the binarization method "Fixed Threshold", the brightness assumes a graylevel value between 0
and 255 as the limit from where the scan result for a pixel will be white or black.
Recommended Value = 165.
With the "Automatic Threshold", the brightness only serves as a threshold for the start value (white or
black) of every scan line.
Recommended Value = 165
With the binarization method "DTplus Threshold", the setting for brightness controls represents which
gray value will be represented as black or as white.
Recommended Value = 165
DTplus Filter
With the DTplus option, filters are available to reduce unwanted pixel "noise". The filter deletes black
and white pixels (despeck function) immediately after scanning, and even before the image is saved.
The table below lists the 60 possible values for the filter. With the value of 0, pixels will not be filtered
out at all. With the value of 1, black specks of 1x1 pixel are deleted. With the value of 16, black
specks of 4x2 pixels size are deleted, and all white specks of 1x1 pixel size (within black areas) are
filled with black.
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