Hello Previously I was able to increase its performance by using graphicsmagick (you can also use imagemgick instead).
http://www.graphicsmagick.org/ Simply download source in Mac OSX and compile. Explore the following option to apply a pre-processor from terminal: gm convert -magnify gm convert -sharpen 6x1 gm convert -gamma 2 gm convert input.png -gamma 2 -colors 2 output.bmp bmp2tiff -c none main.bmp main.tif tesseract main.tif result -l eng But applying these type of filter to all images wont be a good idea! (note you also may need to install bmp2tiff/similar tool in Mac OSX) You can also try with BARCODE!!! reader library, if available. :) regards Salahuddin salahuddin66.blogspot.com On Fri, 2011-01-07 at 06:02 -0800, Wojciech Radomski wrote: > Hi, I am working on iPhone application that recognizes ISBN numbers > (ISBN: 978-83-7380-900-0) I use tesseract for this, but it is not > working very well. I can see other applications, using same engine to > work better. > > to limit the characters i use this config line: > tess->SetVariable("tessedit_char_whitelist", "SN:0123456789X-"); so > all "I" are converted to "1", and "B" to 8. Using this it wont make > mistake with those letters, whick are not important to me. After that > i use regular expression to find the correct part of recognized text. > > I also crop the image, so tesseract recognizes only part of the image, > where isbn is visible (i placed color rect on camera overlay, so user > have to place code in correct place) I also resize the image to 1000px > width (also tried other sizes) > > It works quite well when the light is excellent, but it is really hard > to recognize correctly when the lighting isn't perfect. > > The last digit of isbn number is a control sum. > > What can I do to make it work better? Is there any way to say > tesserect to recognize text only in given regular expression? Maybe i > should do something with image first? > > Sample images, that are not recognized correctly: > http://img412.imageshack.us/i/img0367si.jpg/ > http://img264.imageshack.us/i/img0361d.jpg/ > > At the moment I am also making pictures at 2x zoom so camera is not so > close to the object. It gives better results, but it is easier to move > the camera and take fuzzy image. > > -- > You received this message because you are subscribed to the Google > Groups "tesseract-ocr" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to tesseract-ocr > [email protected]. > For more options, visit this group at > http://groups.google.com/group/tesseract-ocr?hl=en. -- You received this message because you are subscribed to the Google Groups "tesseract-ocr" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/tesseract-ocr?hl=en.
