Thanks for all these answers, Patrick. Regarding speed, that's ok, it was only to have an idea, not precise numbers.
One more question: which revision of 3.01 did you manage to cross- compile? I tried with r552 and r581 without success while it's compiling correctly for the tesseract-3.00.tar.gz available on code.google.com. Thanks, Cyril On Jul 23, 6:10 am, patrickq <[email protected]> wrote: > ScanBizCards actually uses Tesseract 3.01 - I believe the fears > expressed by many on this forum about using "non official" versions of > Tesseract are misplaced. We switched from 2.04 to 3.00 as soon as 3.0 > was made available - and only benefited from it - then switched to > 3.01 quickly - and again experienced significant improvements (and > only rare cases where Tesseract 3.01 did less well than Tesseract > 3.00). > > Tesseract's image processing is acceptable in the case of images with > a fairly uniform background and text with high contrast relative to > the background, such as this > example:http://www.scanbizcards.com/benefitquest.jpg > > Since we very often get images with shadows, bad lighting and > backgrounds with strong colors ScanBizCards applies its own image > processing and calls Tesseract only with a black and white image. This > is what we produce on the above example (in this case results are > identical - and good - without our preprocessing > too):http://www.scanbizcards.com/benefitquest-bw.jpg > > Regarding performance (on iPhone 3GS): > - we spend 3 seconds on image processing for a 1,024 x 768 image > - OCR then takes us 14 seconds, but that's not just Tesseract, > includes time spent in our code > > I can get you performance numbers just for Tesseract if you'd like and > for the iPhone 4, let me know. > > Regarding layout analysis: it's available and it works. I don't know > if there is an API that returns the coordinates of words, we use the > sequence of boxes for each letter then we determine where there should > be a space (we don't trust Tesseract's space decision much) or a > newline and so we have the coordinates of words. Tesseract 3.01 layout > analysis is about the same as Tesseract 3.0 from my limited comparison > > Patrick > > On Jul 20, 11:20 am, Cyril <[email protected]> wrote:> Hi, > > > I have some basic questions before starting a project of OCR > > recognition for the iPhone. > > > I have seen the steps to cross-compile tesseract for iOS but have some > > questions on tesseract roadmap itself: > > 1/ should I start on tesseract 2.4 or 3.0? From my understanding 3.0 > > is not yet stable but has a major refactoring ongoing plus several > > features (including document layout analysis)? The current 3.0 > > "release" is quite far from the head of the trunk, which do not seem > > to compile on iOS, so I am wondering if there is any new release > > (3.01?) planned soon and compatible with iOS? > > 2/ is the accuracy and speed of the 3.0 release better or at least > > similar to the 2.4 release? > > 3/ is the document layout analysis already stable? A particular need I > > have is to be able to get the position of a particular recognized word > > in the document? Is this possible with tesseract? > > 4/ what is the typical preprocessing steps involved in OCR (b&w, > > threshold etc.)? Are they already performed by tesseract or do I need > > to perform them myself? If yes with which library is it usually done? > > Leptonica or OpenCV? > > > I am also interested if you could give me pointers to code samples > > that demonstrate the API usage or tutorials on OCR concepts or on the > > APIs of tesseract. Any pointer to the state-of-the-art of OCR, > > including papers on useful preprocessing techniques impacting > > performance is also welcomed. > > > I have seen that ScanBizCard is using tesseract 3.0. Do you have other > > examples of iPhone applications using Tesseract or concurrent > > solutions (commercial or open-source)? > > > Thanks in advance for all your answers, > > > Cyril -- 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
