The technique of 3D image acquisition has been around for more than twenty years, but the demand for its application has been limited. The market is apparently not so busy until now, but that seems to change. In the past three months, we have received the question: ‘Can you control my machine variably by means of a line scan?’

Conventional automation assumes a predictable product position, for example a precisely known location of a product or packaging on a conveyor belt. The processing on the product can be done blindly, because the position and orientation are known. The result is self-evident and always exactly the same, that is what you can do with automated processes. The downside of these advantages lies in the limitation it imposes on the product supply, which must be such that every product ends up on the tape in the right way.

What if I cannot or no longer want to organize?

For successful processing of random lying products on a conveyor belt, one can think of steering by means of a line scan.

Control by means of a line scan

Line scan is technically not the right word, but popularly a commonly used translation for laser triangulation. The word describes perfectly what we see as human beings: a laser line that scans the passing product. What we call the process does not matter, it’s about the result. From the scan follows a so-called point cloud that forms a three-dimensional model of the scanned product. For that you will be having the best line scan camera now.

The software made for your process gets relevant information from this point cloud

This can be a pick-up point, a place where you have to print, a cut line to open a bag, you can say it.Of course, the system still makes some demands on the product position, so the recognizable detail must be visible from the laser and camera position. That is immediately the only requirement, for the rest it is free. And it does not make the scanner – within a certain range – look at whether a small or large product is looked at, the system is also flexible here, without changing or replacing product-specific holders, guides or molds.

The nice thing about using laser light is that the system is relatively insensitive to ambient light. This is due to the fact that the camera receives a special filter which only transmits the wavelength of the laser source, a so-called bandpassfilter. The light output to be applied is so low in almost all cases that laser safety does not require special measures.Because the position of the camera in relation to the laser source is very important, we build it together on one frame. This is then incorporated in an enclosure that we can optionally run in aluminum or stainless steel and in any desired IP value, whether or not carried out in food grade.

For processes with a strongly changing ambient temperature, additional measures are taken by smart material choices that ensure the calibrated set-up under all temperatures.

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