The main criteria here was that, above all, they should not be "inconvenienced" by this additional control in their production line, in other words, the number of wrongful rejects had to be virtually zero, and bags with a missing label obviously had to be detected and removed from the line.
In itself, of course, a logical question, but many vision systems only have the ability to learn a "picture" which is then compared to the one that passes on the production line or check if certain text is present.
Control industrial bulk packaging
However, because these 25 KG bags do not all move exactly the same on a transponder, you have to deal with crookedness, dents and concave and convex bags so recognizing a picture or reading text can sometimes be difficult if some part of the label is just wrinkled or just a little more convex or concave than taught.
Because we did not need to check the content of the label, but only its presence, we chose a different algorithm that is not critical for the position, wrinkles or shape of the bag, but does check 100% whether the label is definitely present. We do this by counting the number of Light-Dark transitions at the position of the label where we can apply a wide tolerance.
This is because if there is no label present we also see zero Light-Dark transitions because the bag itself is uniform in color. And if there is a label we count at least 50 Light-Dark transitions correctly while all labels have about 200 Light-Dark transitions within the applied algorithm.
Applying this algorithm to counting contrast transitions also eliminates the need to learn labels and allows the customer to easily switch between different labels and imprints without having to do any setting to the vision system!
"From the very first conversation, Vision Partners knew what was important to us and were able to respond well to it whereby we now have a control unit with maximum performance which always works without additional effort for our operators."
