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Counting the number of banknotes in a stack using the optical technology

Hi People.

I am looking at a particular application. I want to build a currency counter. The device will be based on optical technology. What I want to do is, "look" at the side of the stack of banknotes and from there, read the number of notes present in the stack.

There are two possible approached that come to my mind :

1.) The CD-ROM Approach

Here, the light is made to incident on the "side" of the stack and whatever light is reflected back, is read by a device. Now, the number of "gaps" in the light gives us the number of notes. The upside of using this approach will be less complexity in the electronics. The downside will be , this approach will involve moving mechanical parts. (In the form of a light source that 'scans' the entire width of the 'side' of the stack) I've found a patent for this approach. Here's the link.

Here is a list of patents related to this one

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And here is the US patent Number 4694474

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To read the full texts of these patents, u need to make and account on

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Its free.

2.) The image-processing approach An image of the 'side' of the stack is taken by a CCD or a CMOS camera. The image is then passed on to an image processing unit which then processes the image. There can be seen visible distinct 'lines', horizontal lines in the image. Each line representing one note. If we can read the number of such lines, we can build such a device. Now, I've got a patent for this as well. And en extremely detailed one, describing, in detail, the complete hardware, software and the diagrams of the project. Here it is.

US Patent Number 5534690

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But being from computer science background, I am unable to understand this completely. Can someone help me ? I am ready to pay, if someone can make that thing for me. I am based in India.

Ankit

Reply to
Aks
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Offhand I'd think you've a cat-in-hell's-chance of counting to any better than say 60% accuracy. Look at any slab of cut paper and its impossible to differentiate the individual items. Fancy cameras and software will not improve on this. For Currency, the accountants need 100% accuracy, 99.9% is unacceptable.

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Reply to
john jardine

Why are you limiting this to optical methods? The method you propose can't read denominations anway, so why not just weigh the stack on a sensitive scale?

Best regards,

Bob Masta D A Q A R T A Data AcQuisition And Real-Time Analysis

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Scope, Spectrum, Spectrogram, Signal Generator Science with your sound card!

Reply to
Bob Masta

I am not interested in denominations. All I want to know is, how many notes are there in a stack of notes. The size of the stack is of the order of 100 notes. I want this device to be handheld and mobile. It has to be VERY light. And this seems possible only if I use the optical technology.

Ankit

Reply to
Aks

On the contrary, I think using optical technology will greatly enhance the accuracy of the device. The pits on the surface of a CD-ROM disk are much more fine than the gaps between two adjacent notes, or tha width of any note. For the record, the pits on a CD are 0.5-1 micrometer in size. Whereas a bundle of 100 new notes (worst case) is around 7-8 mm - giving the average thickness of one note as 7/100 = 0.07mm or 70 micrometer. Now, if the light can read and distinguish something of the order of

1micrometer, I say, it can DEFINITELY read something of the order of 70 micrometer. I tried taking a picture of a side of the stack of 100 notes. And even there, I could see the notes distinctively. If you have a look at the patents links that I provided, you will find the drawings of this. After magnification, it becomes very clear. A good image processing program, must then be able to 'count' the number of notes.

Ankit

Reply to
Aks

better

to

In the interests of mindless curiosity I looked at a CD with a microscpe and

320X magnification. Each pit was clear and well defined, perfectly visible as a clean, unwavering, string of high contrast white dots with black seperators. Could even have read the binary straight off. Then looked at the edge of a block of 20 sheets of paper (X50, X10 mag' under various light conditions). Yes, the sheets were individually visible. But, I found the sheet to sheet colour and edge contrast quite poor and required the light source to be fiddled with for best results. Also required some shuffling about of the paper to clarify edges where the fibres had splayed and spoiled the seperation line. Can well written software tease out more detail than an eye/brain neural net?. Curiosity satisfied, I'll increase the cat-in-hell's chances to 65% :) 
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Reply to
john jardine

seems kind of tricky..

have you condisered mechanical means?

run a phonograph needle up the stack and count pulses.

Bye. Jasen

Reply to
jasen

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