Capacitive Touchscreen
User Manual H12 / SCAMAX® 8x1 - Version 2019.12
the background has been successfully removed
from the form when applying the default Bright-
ness threshold of 200. Appropriately adjusting
the two other settings has resulted in all gray
areas to be converted into (
predominantly
) whi-
te areas.
After reducing the
Brightness
value to 150, only
notably lower grayscale values are considered
and returned as black pixels, after binarization.
Finally, when further reducing the
Brightness
value to 100, like in this example, only the very
lowest grayscale levels survive (
as black pixels
).
The form’s background information now has
effectively disappeared.
The
Contrast
setting will change the weighting
of image background (
lighter information
) ver-
sus image foreground (
darker information
). The range for this setting (
again
) is 0 – 255, with the setting’s
effect reversing at midpoint: For
Contrast
settings from 0 to 128, the image background will be in-
creasingly attenuated, in relation to the image foreground. Beyond midpoint, the image background
will slowly reappear, with the darker shades of gray being reproduced progressively thinner.
Again, let’s consider the setting’s effect by con-
sidering the sample grayscale image, to the left.
The default value of 30 will ensure that as little
image information as possible is lost. Merely the
gray areas on the form and the gray appearance
of the paper itself are largely suppressed, whe-
reas all other image information is preserved.
Please note that this result, of course, will require
appropriate
Brightness
and
Outlining
settings.
By reducing the
Contrast
setting to 0, the weigh-
ting effect is more or less nullified: Anything
not attributed to the paper’s surface is now
interpreted as foreground information. Note
how dark gray patterns on lighter areas have
been surrounded with white pixels, in order to
preserve legibility
