Rockwell Automation 5370-OCR2 PAK - Manual (Page 30)

Chapter 4
OCR Tool Configuration
4–11
The Threshold / Filter function allows you to adjust the thresholds and
morphological filtering of the OCR Tool. Refer to the CVIM2 Reference
manual (Catalog No. 5370-801) for additional threshold information.
Adjust Thresholds until
image sharpens.
Image within Pick
& Place Window
If the characters to be read are dark printing on a light-colored background,
set the high threshold to its maximum value of 255, and adjust the low
threshold so that the characters are black and the background is white.
If the characters to be read are light printing on a dark-colored background,
set the low threshold to its minimum value of 0, and adjust the high threshold
so that the characters are displayed in black and the background is displayed
in white.
The Morph 1 button allows you to edit the Morph 1 filter settings, which can
sometimes be used to improve the quality of the image. In most applications,
the morphology filtering can be left in its default (Identity) state. Do not use
the Invert morphology operation, this interferes with the tool operation.
Refer to the CVIM2 Reference manual (Catalog No. 5370-801) for
information on setting morphology filters and on the Configuration Editor
display settings.
Note: The appearance of the thresholded image which is displayed can be
affected by the setting of the Character Size, and whether the Scale of the
image display panel has been set to 1 or To Fit in the Configuration Editor.
HINTS:
•
Set the threshold before setting the OCR Tool’s Character Size.
•
Try to obtain the best contrast between the characters and the background
without distorting the characters.
•
Adjust the threshold so that you have a consistent ”stroke width” of
characters between the teaching and running OCR.
•
A Light Probe can be used to reduce variation in image brightness. Refer
to the Camera section of the CVIM2 Reference Manual for more
information.
Set Threshold / Filter