To whom it may concern,

Just created a tesseract 3.04 trained data (see attached). 
I call it "MRZ" because it has the OCR-B as the only font and trained with 
characters A-Z, 0-9 and the lesser-than symbol (<). Seems to be fast and 
accurate in my projects.

On Monday, June 24, 2013 at 6:58:47 PM UTC+2, Nick White wrote:
>
> Hi Peter, 
>
> Sorry for the lack of response, I think us regulars here are all 
> quite busy at the moment. 
>
> Have you searched the archives of this mailing list? I seem to 
> recall someone previously deciding to go with a different project 
> which focused just on MRZ recognition. 
>
> Tesseract will do a reasonable job, as you have found, but perhaps 
> a dedicated program could do even better (and for less effort on 
> your part). 
>
> As far as improving your Tesseract results, though, I'd recommend 
> looking into user_patterns. It isn't well documented, but if the 
> format you're expecting is predictable it should help. Also have you 
> set up a unicharambigs file? That may help a little too (not much, 
> but it's probably worth adding for the common cases of 5 -> S, 8 -> 
> B, etc). 
>
> > One more unrelated question. How to read data from image with 
> non-standard 
> > orientation 
> > (upside down, rotated left/right by 90 degrees)? How to use OSD feature? 
>
> I confess I don't actually know. I think Tesseract might try to 
> guess this entirely by itself. Does anyone else here know any 
> better? 
>
> Once you're happy your MRZ training is as good as it will get, would 
> you be happy to have it added to the main Tesseract repository? If 
> so (and it'd be great if you were) open an issue on the bug tracker 
> with the training file, and add some comments to the top of 
> mrz.config about how it was created and where the source files for 
> it are (see my grc.traineddata for an example). 
>
> Thanks Peter, and sorry again for not getting back to you sooner, 
>
> Nick 
>
> P.S. One other thing I just thought of: is the DPI you're feeding 
> into Tesseract the same as the DPI you trained with (300)? Ideally 
> it should be. Also you're right to preprocess using thresholding; 
> Tesseract isn't particularly good at that step and it's much better 
> if you can do it first. 
>
> On Wed, Jun 19, 2013 at 11:45:10PM -0700, Peter wrote: 
> > Hello. 
> > 
> > I'm trying to train Tesseract for OCR. My goal is to be able to 
> recognize text 
> > from MRZ zone of various documents (mainly national ID). The training 
> process 
> > should be pretty straightforward and I'd expect good results since all I 
> have 
> > to deal with is one font (OCR-B), capital letters of Latin alphabet 
> (A-Z), 
> > digits 0-9 and "less than" sign (<). Unfortunately the results are worse 
> than 
> > expected. While the effects for preprocessed images (thresholding using 
> GIMP) 
> > are pretty good (not perfect - in many cases Tesseract treats 0 as O, 
> sometimes 
> > treats 5 as S and occasionally inserts unexpected whitespace between 
> letters), 
> > data taken directly from an unprocessed scanned image is rather poorly 
> > recognized. There are many cases where Tesseract thinks O is 0, 5 is S, 
> 8 is S, 
> > 2 is Z, H is M, U is W etc. While 0 vs O case can be tough (OCR-B 0 and 
> O don't 
> > look too different) and perhaps beyond Tesseract capabilities, I think 
> other 
> > ambiguities can and should be eliminated. As I'm new to Tesseract (have 
> been 
> > using it for just a few days now) I hope you can suggest me the optimal 
> > training for OCR-B font or even provide me with some good training 
> sample. 
> > Here's what I did to train Tesseract: 
> > 
> > 1) Prepared training text with OCR-B font (train1.odt, see attachments), 
> > converted it to .pdf with LibreOffice Writer (train1.pdf, see 
> attachments) 
> > 2) Opened train1.pdf in GIMP and saved it as 300 dpi tif (resolution: 
> 2479 x 
> > 3508), can't attach it as its size is more than 30 MB 
> > 3) Prepared font_properties file with the following line: ocrb 0 0 1 0 0 
> > 4) Executed the following Tesseract commands: 
> > 
> > tesseract mrz.ocrb.exp0.tif mrz.ocrb.exp0 batch.nochop makebox 
> (corrected 
> > mrz.ocrb.exp0.box included as attachment) 
> > tesseract mrz.ocrb.exp0.tif mrz.ocrb.exp0 box.train 
> > unicharset_extractor mrz.ocrb.exp0.box 
> > shapeclustering -F font_properties -U unicharset mrz.ocrb.exp0.tr 
> > mftraining -F font_properties -U unicharset mrz.ocrb.exp0.tr 
> > cntraining mrz.ocrb.exp0.tr 
> > 
> > changed shapetable, normproto, inttemp, pffmtable, unicharset names so 
> that 
> > they're prefixed with mrz 
> > 
> > combine_tessdata mrz. 
> > 
> > To read data from images, I run: 
> > 
> > tesseract -l mrz <image_file> output 
> > 
> > Is there anything that can be done better? Maybe my training file is not 
> good 
> > enough? 
> > If that's the case, can you please provide me with a better one? 
> > 
> > One more unrelated question. How to read data from image with 
> non-standard 
> > orientation 
> > (upside down, rotated left/right by 90 degrees)? How to use OSD feature? 
> > 
> > 
> > 
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