Vision Sensor SBSI/SBSC-EN, 8062650 - 1607b - 13/09/2016
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Vision Sensor Manual
values of the pixels in the corresponding position do have lower (darker) values, the score value is
significantly lower than with the contact mounted.
But, as also big regions of the search area are matching (the outer dark frame of the black plastic) the
score value is not zero, but approx. 70%.
The settings in these examples are just made to illustrate the function of the detector pattern matching. In
real operation these settings should be optimized further. (E.g. by smaller search and / or feature regions
>> relevant pattern gets more significant, etc.)
By Teach the pattern inside the red frame gets stored in the sensor as reference pattern. Size and
position of the reference pattern is defined by the red frame. In Run mode the SBS tries the find the best
fit of the reference with any region in the image. Depending on the settings of the threshold the object /
feature is detected or not. The function pattern matching does not work with rotated images; it´s
tolerance is limited to an angle of approx. +/- 5°. Patterns with higher angular deviation are not detected.
This behaviour can be used to detect if a part is in correct orientation in feeding application.
Example:
The following pattern was taught:
Fig. 82: Pattern, reference
With the following three examples, the object is detected with 100% concordance, as the taught pattern
is exactly the same, even though it is in another place on the image.
Only offset in X or Y direction and not rotated.
Fig. 83: Pattern, positive result
With the three now following examples in the second row, the object is also detected, but with less than
100% concordance, as it deviates from the taught pattern in some pixels. Good or bad results are supplied
according to the setting of the threshold value (degree of concordance).
Fig. 84: Pattern, limit case
Pattern detection tolerates a ± 5 degree rotation. This means, the images in the bottom row were also
detected, although the actual degree of concordance with the sample image is less than 100%, despite
100% pixel concordance.
Patterns with a larger degree of rotation are not detected.
This can be used as a function e.g. for detection of the correct alignment of parts on feeding units.
Summary of Contents for SBSC-EN
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