Different output on same text picture sometimes

[Gokcer Gunes]

Examples is at above,what i am doing wrong?

[Gokcer Gunes]

Btw im using charles's wrapper 3.02 tesseract

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[Allistair C]

Your question is not self-evident, what are you trying to ask? Can you present your OCR results for each test you are conducting?

[Gokcer Gunes]

yeah resul pictures are in message you cant see them?

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[Gokcer Gunes]

i uploaded them as pictures 

[Allistair]

I see the pictures, yes, but I don't understand the question. Can you elaborate in detail what the issue is?

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[Gokcer Gunes]

they are input image and output result ,inputs have same first line but in first output M is correctly converted to M but in 2. output M is converted to H

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[Allistair C]

Ah, I see - interesting :) The 2nd example isn't quite the same - it seems to have some noise on the left hand edge. Also, what PSM are you using? Can you send original size images you send to Tesseract?

[Gokcer Gunes]

ah no its not noise there is no noise in original img it just result of crop in paint

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[Gokcer Gunes]

yes i will get and upload them asap

[Gokcer Gunes]

First original Image which sended to tesseract

Second Original Image which sended to tesseract

and outputs are in image which you already saw

[Allistair]

Well, I must say I am unsure why one image works for that line and not the other. Clearly the addition of other lines of text is causing Tesseract's classification system to go slightly awry - must be learning something with the addition of the new text that it feeds back to the 1st and gets it wrong.

However, I was easily able to get a perfect read on both of them by performing a simple threshold filter (turning all text dark black) before providing to Tesseract.

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[Gokcer Gunes]

i tried with threshold filters too but i didnt get good results,best result for me was this way.Can i ask what threshould number you used for this images.

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[Allistair]

This is the image I am providing to Tesseract

https://dl.dropboxusercontent.com/u/523401/code.png

It's your image with a quick threshold performed in Photoshop. Notice that you need to ensure the threshold makes all text black.

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[Allistair]

Oh, I also scaled the image up to 2000px wide. Larger images often work better with Tesseract so a pre-filter or sampling up can help.

[Gokcer Gunes]

Yeah with more size it works better and better but it takes more time also thats why im only scaling 2x around.And can i ask did you try with only threshold or threshold+scaling

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[Gokcer Gunes]

And also can i ask if tesseract can detect point between lines,so i can crop lines and send each line as different picture to tesseract?

[Allistair]

It works for me with just the threshold and no scaling (however, there is an error in the 2nd Kaliko where the l is misrecognised as a 1):

https://dl.dropboxusercontent.com/u/523401/codethres.png

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Memorystream memstream = new MemoryStream();

bitmap.Save(memstream, System.Drawing.Imaging.ImageFormat.Png);

Kalikolmage imgklk = new Ka1ikoImage(memstream);

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[Gokcer Gunes]

and also why is that? i mean at 3. line there is both  KalikoImage which is same,but first is correctly translated to text and second one is with one mistake

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[Allistair]

:) I hear you, I do. From the input image perspective I looked at the 2 Kaliko words and they match at the pixel level. Some part of Tesseract's internal classification system is falling over a bit here, I cannot tell you why, I can only say that OCR is not a perfect technology. It works on machine learning and classification of probabilities. What seems simple to us is not necessarily so to the OCR engine. It could be that by the time it gets to the 2nd Kaliko it thinks it has improved the 'l' recognition from the previous text to be a '1' - Tesseract has this adaptive classifier - but I am only guessing, maybe others have better ideas.

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[Gokcer Gunes]

And i did threshold too and i got same results with you for this inputs ,but for some other inputs threshold causes them to recognize wrong such as * recognizing as ' .My images recognizing great for single line and with 1-2 mistake for multiple lines so i need to solve that.Thanks for great response and i will be very happy if you can return me ever got idea what causes that problem:).And also a last thing  can i detect points between lines with tesseract to seperate image into multiple single line image?

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[Allistair]

No problem. Not sure I understand what you mean by detect points - a point to me is an (x, y) coordinate. Do you mean space? In any case, Tesseract is not going to do anything like that I think - you will need to perform image preprocessing to do that using Open CV or something.

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[Gokcer Gunes]

yes i mean yes like any point in space between lines,so i can say say "crop area that between y1 and y2 points".Because i think tesseract able to detect lines ,so i thought i can get mininum bottom point of first line words and top point of 2. line words

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[Gokcer Gunes]

So not possible with tesseract?

[Allistair C]

No they best you could do is look at one of the many config params to see if you can influence the engine, e.g disable adaptive classifier (not sure if that's possible or even beneficial) but whatever is causing your issue might be targetable via config but the config is not very well documented . If you wanted to feed line by line you would need to do that outside of tesseract and may be easier than the config method.

Sent from my iPhone

<temppng.png>

Second Original Image which sended to tesseract

<temppng.png>

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[Gokcer Gunes]

Okay understand ,thanks for great help and have a nice day:)

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[Gokcer Gunes]

hi me again, is there any other forum  i can ask about turning off that adaptive modifier? i mean people who deal with config parameters etc

[Allistair]

Try turning it off to see if anything useful happens ...

classify_enable_learning 0

classify_enable_adaptive_matcher 0

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[Gokcer Gunes]

im using c# winform  application,can i ask how to do that command in c#:)

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[Allistair]

Look up your platform's way of calling SetVariable.

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[Gokcer Gunes]

finaly i was able to change it but no luck even turning off:( ,thanks for your time:) and if i send mail to raysmith about this problem, any chance will he reply?

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[Allistair]

Doubt it, I tried once ;)

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[Gokcer Gunes]

okay thanks again ,then i will play with some parameters to see any changes by any luck:) have a nice day:)

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