Excellent article. Being a self-taught CSS/HTML/Jquery front-end developer (and SEM Acct. Manager by Day) the nuts and bolts of image recognition were black magic to me. This was a fantastic read.
When you think about it, this is actually totally useless. It is much easier to just generate a puzzle on the fly and not require the user to have a paper copy of it.
But I bought it anyway, because the point isn't to solve Sudoku puzzles, it's to show off how nifty this program is. Which is easily worth a buck.
An app like this could solve the puzzle in your newspaper faster than you could transcribe it. I would love to see more OCR apps which are even more useful. Where's the app to scan a barcode or ISBN of a book and have it populate with the information from Amazon and a link to download the e-book?