Panasonic IMAGECHECKER PV230 Manual page 24

Setting Procedure
1.
Select "Dynamic" in "Threshold method".
2.
Select "Light" or "Dark" compared to characters in "Background (Dynamic)".
If the background is brighter than the characters, select "Light". If it is darker
than the characters, select "Dark".
In the right example, select "Dark" for cutting out the upper white
characters, and select "Light" for cutting out the lower black characters.
3.
Select a size to average brightness in "Average Size".
Set a value which is about the same or twice as much as the size of a segmented character. However, the
appropriate value will vary according to conditions. Decide the value checking the segmentation result.
4.
Set "Offset" value.
When the contrast between the characters and background is high (black characters in white background,
or white characters in black ground), set a high value, approx. 30 to 50 for the offset value. When the
contrast is low, set the offset value to around 10.
5.
Execute Segment with the F2 key, and readjust "Average Size" and "Offset" checking the displayed
segmentation results.
When the target characters cannot be cut out, also use "Segment pre-process filter" mentioned in the next
page for the adjustment.
If an unexpected result is displayed when confirming the segmentation result with the F2 or F3 key, the
image may not have been captured.
In such case, run the test (press the TRIG button) to capture the image, and press the F2 key or F3 key
again.
With dynamic thresholding, reliable segmentation can be performed because the object is binarized after
the reduction of color unevenness.
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