Subject:
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Re: Barcodes & error detection
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Newsgroups:
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lugnet.robotics
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Date:
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Thu, 8 Sep 2005 14:15:00 GMT
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Viewed:
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1176 times
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> First, there is slight variation in the barcodes themselves that may
> negate this (light sensor inclined 2 degrees to the west will still be
> perpendicular if a section of the barcode is inclined 2 degrees to the west;
> rare, yes, but the error rate is already only 3%).
I had in mind a steeper angle - let's say 20-30°. Light sensor optics is very
primitive!!!
> Second and more critically,
> to distinguish all three "colors" (white, black, and highly reflective) (...)
> Using retroreflective white tape (...) would seem to work, but actual tests show that it often
> can't be distinguished from white.
Serious objection... From my laser sensor experience, I tend to think that
retroreflective tape would work well, but maybe not enough to separate from
white. Experiment needed!
Rob's suggestion about ambient light shielding is very wise too...
Philo
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Message has 1 Reply:
 | | Re: Barcodes & error detection
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| (...) Oh. I'd not thought of that at all. At those angles, the shroud design and the size of the "window" the light sensor can see through get to be tougher problems. (...) It may be because a good retroreflector won't work in this situation - the (...) (19 years ago, 8-Sep-05, to lugnet.robotics)
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Message is in Reply To:
| | Re: Barcodes & error detection
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| (...) Absolutely, but in any real world application there is almost always some error rate. (...) John Barnes also suggested that to me after I posted, and I'm embarassed to admit that the thought hadn't occured to me. I need to test (again), but (...) (19 years ago, 8-Sep-05, to lugnet.robotics)
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