Author Topic: a robot capable of distinguishing individual sheets of paper  (Read 2386 times)

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Offline dmehlingTopic starter

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a robot capable of distinguishing individual sheets of paper
« on: August 01, 2007, 04:59:28 PM »
I have a question that could be rather far out, but potentially doable as well.  I am building a robotic book scanner and I plan on using some kind of arm to pick up an individual page in order to turn it.  However, because of the nature of pages sometimes wanting to stick together, it might occur frequently that I end up picking up more than one page with my arm.  I was wondering if there was a way of sensing if more than one page was lifted up.  I made a rough measurement and calculation and determined that the average page thickness is .02 mm, so my sensor would need to be able to distinguish something that minuscule.  Is this something that should be done optically, or would it be better to use infrared or ultrasonic methods for measurement?  Even better would be a consistent method of lifting up a page that would yield an error rate of 1% and then manually rescan the few pages that were missed.

Offline airman00

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Re: a robot capable of distinguishing individual sheets of paper
« Reply #1 on: August 01, 2007, 05:42:56 PM »
For picking it up why not put a fan  from the side and an arm to pick it up. The fan would be blowing at low speed and when the arm picks up a piece of paper( using a vacuum maybe) the wind from the fan unsticks papers. The fan would have to be at a certain position to unstick the papers....
I just think it might work in theory. Try to pick up a page from a book and when picking it up blow on it form the side. I think that blowing and holding will allow only one page at a time to be picked up.
If you find out why papers stick then you might be able to find a solution for that problem. Maybe something to do with cohesion or some chemistry thing.( ???)
Hope that helped
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Offline Gertlex

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Re: a robot capable of distinguishing individual sheets of paper
« Reply #2 on: August 01, 2007, 11:40:49 PM »
A variation of sorts on airman's fan idea is to use a weak vacuum to pull a page up, and then have the grabbing mechanism auto grab in the space where the page should be.  With an IR sensor on the grabbing mechanism, you could even detect if there's a page... If no page, then try again with a bit more power to the vacuum.  Only run the vacuum for a short period: long enough for the grabber to have a chance to get under the page before it falls again.
I

Offline dmehlingTopic starter

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Re: a robot capable of distinguishing individual sheets of paper
« Reply #3 on: August 02, 2007, 12:00:44 PM »
What about using an IR rangefinder?  If two pages were stuck together could it distinguish the two by determining the distance between it and the first page, and make the same determination of the distance with the second page, and the small amount of space in between the two pages would register a much higher distance? Could it work if say the space between the two pages were about a millimeter?

Offline dunk

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Re: a robot capable of distinguishing individual sheets of paper
« Reply #4 on: August 02, 2007, 12:21:42 PM »
so the way this is done in the trade is to slice the bindings off the book and use a sheet feeder similar to a printer sheet feeder to seperate them.

it's only an option if you don't mind destroying you book though.


if you want a none destructive method i'd use a vacuum pump to lift each page, scan the page, then use text recognition software to read the page numbers to see if you missed one.

IR range finders would not be sensitive enough to detect a page thickness but what about shinning IR through the page being turned?
look for how much light shines through.
you would obviously need to recalibrate for each book but it might be possible.

dunk.

Offline dmehlingTopic starter

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Re: a robot capable of distinguishing individual sheets of paper
« Reply #5 on: August 02, 2007, 12:36:34 PM »
I like the idea of shining a light or IR through a page.  However, would that work with pages that are very thick and glossy?

 


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