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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