Determine orientation coin (Vision)

HenryLamboo · Oct 9, 2006

We are designing a machine for edge inscription for coins. The orientation from the coin have to be determined to start the edge inscription always on the same position.

I am thinking of using Vision to determine the orientation of the coin. If you take a picture of each degree of the 360 degrees radius it will take a long time to determine the orientation of the coin.

Is there a better way to determine the orientation of a coin?

Are there vision systems who accept a distortion of a few degrees?

Which vision sensors (supplier) can you use?

keithkyll · Oct 9, 2006

A few degrees of distortion is a problem. Digital data from an out-of-focus image will be worthless.
Consider 2 cameras and 1 video card. Orientate using the face of the coin. After orientation, switch to the edge camera.
Cognex are the experts in this field.
Are the coins all the same diameter? Build a special curved lens.
You don't need to look at 360 points. Let's say the text covers 25% of the edge. Read, rotate 10%, read, until your OCR recognizes one or more characters. Then you can do a fine search within the area.

Doug-P · Oct 9, 2006

Never done it so take this for what it's worth.

It seems it might be possible to determine orientation with a set of proximity sensors picking up selected features on the coin's face, if you can position them such that they all turn on at only one point in the rotation.

.02

Peter Nachtwey · Oct 9, 2006

HenryLamboo said:
I am thinking of using Vision to determine the orientation of the coin. If you take a picture of each degree of the 360 degrees radius it will take a long time to determine the orientation of the coin.

A good vision system should need just 1 picture. The picture can be rotated in software.

Is there a better way to determine the orientation of a coin?

I am not current on the latest technology or software but I do know that it isn't necessary to use the data from the whole coin. Just the most distinguishable feature.

HenryLamboo · Oct 10, 2006

keithkyll said:
Are the coins all the same diameter?

No the coins are not all off the same diameter.

keithkyll said:
You don't need to look at 360 points. Let's say the text covers 25% of the edge. Read, rotate 10%, read, until your OCR recognizes one or more characters.

The text could be 100% of the edge. The machine we have to build prints the text on the edge. There is only a face at the coin.

Doug-P said:
It seems it might be possible to determine orientation with a set of proximity sensors picking up selected features on the coin's face, if you can position them such that they all turn on at only one point in the rotation.

I don’t know if this is possible.

Peter Nachtwey said:
A good vision system should need just 1 picture. The picture can be rotated in software.

I know that Omron can do that but do you know other suppliers. I need a standard solution for this.

Thanks a lot for all the answers.
If you have other suggestions please let me know.

Determine orientation coin (Vision)

HenryLamboo

Member

keithkyll

Member

Doug-P

Member

Peter Nachtwey

Member

HenryLamboo

Member

Similar Topics