Tuesday, November 23, 2010

Another line scan application

It was a story on the Quality Digest web site that prompted me to check out German machine vision integrator, ibea. The story was about system that inspects brake discs for flaws – “Everything Is Under Control” (written by Xing-Fei He of Dalsa,) if you want to go to the source.

The details, insofar as they are made available, are pretty interesting: 3 Dalsa Spyder 2 line scan cameras look at the top, bottom and outside edge in under 10 seconds. Somewhat confusingly, we’re told that the illumination is darkfield yet the image, as shown in the screenshot, appears to show what looks more like bright field lighting. Also, there’s no information on the vision libraries used but I’m guessing it’s not Sapera since the Dalsa author would surely have told us. More likely then, it’s either Halcon or Common Vision Blox.

Fortunately though, ibea have been kind enough to provide a video of the system, which I attach below for your edification. (Or use this link.)

One curious aspect of this system is that ibea appear to used a combination of red and green lights. I suppose it could be that they just liked the color effects but I suspect there’s an altogether more scientific/technical reason. My guess is that using appropriate bandpass filters allows simultaneous capture from multiple cameras without having one set of lights interfere with another.

Well that’s my guess. Let me know if you have a better idea.

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