Including
technical details in an application press release lets us all improve
our knowledge and advances the machine vision industry. Dalsa,
inspect-online.com, and end-user Accuma are to be commended for doing
just that with “From
Pole To Pole”
published April 12th
2013.
This
describes an assembly verification task performed at Accuma where
cylindrical posts are measured to ensure the assembly is correct. The
solution consisted of a backlight and a Dalsa
Boa smart camera.
Two
particular issues are described: the need to locate the post in the
image, and the importance of ease-of-use and supportability. The
first seems to have been addressed by using some sort of fixturing
tool to locate the part in the image. (I know that’s obvious to you
grizzled vision Pros but it’s not obvious if you’ve never done it
before.)
The
second issue was addressed by the choice of the Boa camera itself. I
have no personal experience but the quote from the Maintenance
Supervisor, “"We learned how to program the vision system
using the manual that came with the product and we haven't needed any
training,"” I found pretty telling. I found the same when I
used the latest Keyence vision sensors. (“Easy
setup, thanks to Keyence”
May 1st,
2013.)
I
would however make a couple of observations on the details of the
application.
We’re
told an 8mm lens was used. That’s a wide angle of view, so the true
diameter of the post isn’t really seen. I would try to go with a
longer focal length lens with a narrower viewing angle. Also, given
that there’s measurement going on, I would (a) be concerned about
the consistency of the working distance from post to lens (if it
varies the scale changes,) and (b) want to see some kind of
calibration target and process form part of the inspection.
But
also, and to show that I can praise as well as criticize, I note that
the backlight is some distance away from the post being measured.
That’s a good thing because it reduces reflections off the
cylindrical post and has the effect of making the lighting
“pseudo-collimated”. (Further away would be even better.) Any
time you’re backlighting, try to do the same.
So,
a good article about a good application, and I’m sure there’s
something we can all learn.
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