Rockwell Automation 5370-OCR2 PAK - Manual (Page 12)

Chapter 2
Introduction to OCR2-PAK
2–4
The following requirements must be met for character recognition.
Character Orientation and Direction
The OCR Tool inspects only horizontal strings. If your characters are
rotated, you can use the Build Reference Tool as described in the CVIM2
Reference Manual to rotate the OCR Tool prior to inspection.
Vertical String
Bottom-to-Top Orientation
Tool must be Rotated -90
_
Vertical String
Top-to-Bottom Orientation
Tool must be Rotated +90
_
Non-Recognizable Orienta-
tion As Single String
Horizontal String
Note: The Non-recognizable example above could be inspected using 3
strings in one OCR Tool.
Character Height
It is recommended that the height of the characters in the inspected image
be at least 24 pixels. Although it is possible to read characters which are
smaller, the reliability of the inspection may be reduced. For best
reliability, the characters should be at least 32 pixels high. Characters may
be as tall as desired.
The inspected characters must be approximately the same height from
inspection to inspection, but the OCR Tool can be reconfigured to handle a
change in character size. If text appears in more than one size on a single
image, different OCR Tools, with different character sizes, must be used.
Thinning of the taught character may provide some tolerance to small
changes in size. If all of the inspected characters are increased or decreased
in size by the same amount, you can use the Rescale function to reconfigure
the tool to the new character height. This eliminates the need to re-teach a
font when the height of the inspected characters changes.
Character Requirements