Comments on: Extreme Sudoku Solving with Ruby

By: huogang

huogang — Wed, 19 Mar 2008 12:29:27 +0000

use imagemagick to convert the image to a pgm file then use `gocr -i file.pgm` to get the ocr text from the command line tool inside of ruby.

By: gee

gee — Tue, 23 Jan 2007 07:48:49 +0000

hi.. can you help me.. how to calculate checksums of ocr code at wafer..
if you know..mail me pls..

By: matt

matt — Mon, 16 Oct 2006 22:56:05 +0000

Hi Dan,
The idea is that you prepare a set of known ‘specimen’ images in advance of running the program, and apply the same preprocessing steps to those. Then, for each square in the grid, you do the pixel-by-pixel diff against each specimen image in turn, and select the one with the smallest difference. (In my case I also calculated a rough margin of error by comparing that figure with the next best one.)

I’ve put the complete OCR portion of the code here: http://matt.west.co.tt/files/ocr_example.rb

By: Dan

Dan — Mon, 09 Oct 2006 16:24:08 +0000

Hi Mathew,

Loving this example. I am a big Ruby user and I would like to utilize your the OCR code from your example. I don’t really understand how your are coming back with the “Error” figure, I can see there is a diff which produces this results but I am not sure which two images should be diffed in this fashion.

Any help would be greatly appreciated.

Cheers

Dan

By: poke

poke — Thu, 03 Aug 2006 12:29:27 +0000

Hi Mathew.
Nice article. Try imagine your digit bitmap like a 2D probability function. For OCR you can use high probability central moments (variance, skewness, kurtosis) and not only first moment.
Calculate this moments for your unknown bitmap and compare with moments of typical digit bitmap. It’s basic example of machine learning and image processing. :-)

More about moments you can see here: http://en.wikipedia.org/wiki/Moment_%28mathematics%29

Caio,
Poke

By: icabod

icabod — Wed, 26 Jul 2006 19:52:14 +0000

Of course I mean that in a nice way.
I’m actually interested in the OCR technique as I was looking at doing some simple OCR from an image a little while back. The tricky bit for what I was looking at was that the background was semi-random, as the text was essentially shown over a moving image. Makes life tricky.

I look forware to your write-up.

By: icabod

icabod — Wed, 26 Jul 2006 19:50:26 +0000

Dude, you’re wierd.

Clever. Extremely clever. Everso extremely clever. Incredibly everso extremely clever.

But wierd ;)