How to detect possible presence of barcode in image? (When value cannot be read)

I have a multi-page document that is being scanned. Sometimes, either because the document was a fax or simply a bad scan, the barcode reading software cannot determine the value of the barcode.开发者_如何转开发

The barcode could be on any page within the document, however, this page should be the "header" page and moved to the front. How can I automatically detect that the image has a barcode when the value cannot be read with typical barcode reading tools?

The usual barcode type is Code39, but sometimes it could be DataMatrix. I am mostly concerned about detecting mis-read Code39, as I think it will be easier to detect.

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Maybe take a look at: http://code.google.com/p/zxing/