Measures For Optimizing Object Recognition - Siemens SIMATIC VS120 Operating Instructions Manual

Image processing
4.3 Generating models and detecting orientation
Example for declaring the Precision parameter
A wall is hung full of A4 sheets on which various texts have been printed. An observer has
the task of finding a specific sheet among all the others.
Procedure:
• To accelerate the search, the observer stands at a considerable distance from the wall.
• The observer begins to presort all the sheets. If the observer is looking for a large rough
• If the observer concentrates on details, such as text format or heading, he would move
• Once the observer has made a rough selection, he moves closer to the sheets and
The algorithm of the SIMATIC VS120 Vision Sensor works in much the same way as the
example described above.
4.3.2

Measures for optimizing object recognition

Problem: Object was not trained
If the object could not be trained, the reason may be that there were not enough contours in
the selected ROI.
Remedy
• Make sure that the ROI is selected correctly (position and size) and that the object is
• If this problem still occurs, the object to be trained has too few contours. In this case, a
4-6
Note
If exposure is set to "Manual" and the user changes the precision in the adjustment
support (adjust sensor), the "shutter speed" exposure parameter is adjusted
automatically. Depending on the distance of the object to the camera, this can cause
inaccuracies.
The distance from the wall selected by the observer depends on the criteria on which the
search is based, among other factors.
drawing, they will stand a long way away to be able to see all drawings at the same time.
In this case, the observer would select "Fine3".
closer. Since he is examining more details, the search takes correspondingly longer. In
this case, the observer would select Fine2 or Fine1.
investigates each sheet in detail. He now exactly compares individual words and image
details with a reference sheet. The observer no longer examines each sheet in detail
because he has already limited the selection.
within the ROI when training.
change in the setting of the precision towards greater precision might help, for example,
from Medium2 to Medium1 or to Fine1.
Vision Sensor SIMATIC VS120
Operating Instructions, Edition 02/2006, A5E00757507-01