Instruction Manual

Programming Basics 7-9
14. Using the Position Controls, move the dispensing head to the lower left-hand corner (LLHC)
of the tutorial board and center the crosshairs on the dot in the LLHC.
15. Click on
Teach.
16. Click on
Done.
> Now you are asked to select the method for defining the first fiducial.
> Notice the choices for fiducial finding offered below the video display window.
17. Select the
Model Finder method.
18. Click on
Next.
> Notice the smaller white-lined box in the video display window. This is the Model
Window, the area which will be defined as the fiducial.
> For the first fiducial, use the same dot used to define the workpiece origin.
19. Using the Position Controls, align the camera crosshairs with the center of the dot.
> Notice the tabs below the video display,
Image, Run Time and Model Finder.
20. Adjust the
Model Size parameters if necessary.
> The
Model Window should be as small as possible, but larger than the fiducial feature.
> You may want to use one half of the dot or a quarter of the dot as the fiducial. If the
fiducial fills the entire
Model Window, it is not a good fiducial.
21. Adjust the
Search Window parameters if necessary.
> The
Search Window is the area in which the vision system will search for the fiducial.
> The default values for the
Search Window parameters are equal to the dimensions of the
video display window.
22. Adjust the
Accept and Confusion Thresholds if necessary.
>
Accept Threshold is a minimum “score” that a feature must meet or exceed to be
considered a candidate for the desired fiducial. When the vision system finds a potential
fiducial, it assigns a score to the feature based on how well it matches the previously
taught model. If the score of the potential fiducial does not meet or exceed the
Accept
Threshold
, the vision system will automatically disregard the feature and continue
searching. Recommended setting: 500-800.
>
Confusion Threshold is the maximum score that could be assigned to a “wrong” feature
in the field of view. If a feature scores higher than the
Confusion Threshold, the vision
system concludes that it must be the correct feature and immediately terminates the
search. If a feature scores above the
Accept Threshold, but below the Confusion
Threshold
, the vision system will flag the feature as a “candidate” match, but will
continue searching for a better match. The
Confusion Threshold should be set greater
than or equal to the
Accept Threshold. Recommended setting: 500-900.
>
Camera Settling is the amount of time (in mSec) that FmNT will wait after moving to
the fiducial location and before searching for the fiducial. This allows for the dampening
of any vibration that may interfere with the fiducial search.