Monday, October 22, 2012

Directional light

Ah yes, lighting. The bane of our machine vision lives. One of the challenges we face is that what works for item A on our conveyor may not work so well for item B, even though they come off the same machines and travel down the same conveyor. So when designing a system we spend hours … make that days … trying to find an optimal solution.

How about just using different lights? When space allows, this can be an effective solution, but sometimes it’s not possible. In desperation I have even resorted to placing a mask over regions of my lights, thus Mask A for item A and so on.

But wouldn’t it be easier to have control over each LED?

The RL28Q and RL16Q from Oregon-based Orled (ORegon–LED?) go some way towards this illumination nirvana. These ring lights provide independent control over four quadrants, so you can chose to cast a shadow in a particular direction, for example. (Something that might help with detecting topographical defects, for example.

Now my impression is that these lights are really intended for use with microscopes, where a person viewing would switch quadrant as necessary. But I’m pretty sure that, with a little ingenuity, segment-switching could be automated for a machine vision application.

And that might make lighting just a tiddly bit easier.

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