Yes. This is a very good write-up and helpful to traininers. 2019年7月20日土曜日 0時43分56秒 UTC+9 shree: > > Very well written. You may want to update the wiki pages with the info too. > > On Fri, Jul 19, 2019 at 7:45 PM Arno Loo <arno....@gmail.com <javascript:>> > wrote: > >> I went and tried to understand the source code as well as I could and >> although I did not find all the answers I did find some. (for tesseract >> 4.0.0-beta.3) >> At iteration 14615/695400/698614, Mean rms=0.158%, delta=0.295%, char >> train=1.882%, word train=2.285%, skip ratio=0.4%, wrote checkpoint. >> >> In the above example, >> 14615 : learning_iteration >> 695400 : training_iteration >> 698614 : sample_iteration >> >> *sample_iteration* : "Index into training sample set. (sample_iteration >> >= training_iteration)." It is how many times a training file has been >> passed into the learning process >> *training_iteration* : "Number of actual backward training steps used." >> It is how many times a training file has been SUCCESSFULLY passed into the >> learning process >> >> So everytime you get an error : "Image too large to learn!!" - "Encoding >> of string failed!" - "Deserialize header failed", the sample_iteration >> increments but not the training_iteration. >> Actually you have 1 - (695400 / 698614) = 0.4% which is the *skip ratio* : >> proportion of files that have been skiped because of an error >> >> *learning_iteration* : "Number of iterations that yielded a non-zero >> delta error and thus provided significant learning. (learning_iteration <= >> training_iteration). learning_iteration_ is used to measure rate of >> learning progress." >> So it uses the *delta* value to assess it the iteration has been useful. >> >> What is good to know is that when you specify a maximum number of >> iteration to the training process it uses the middle iteration number >> (training_iteration) to know when to stop. But when it writes a checkpoint, >> the checkpoint name uses the smallest iteration number >> (learning_iteration). Along with the *char train* rate. So a checkpoint >> name is the concatenation of model_name & char_train & learning_iteration >> >> ------ >> >> But there are still a lot of things I do not understand. And one of them >> is actually causing me an issue : even with a lot of iterations (475k) I >> still do not see any log message with the error on the evaluation set. >> At iteration 61235/475300/475526, Mean rms=0.521%, delta=2.073%, char >> train=9.379%, word train=9.669%, skip ratio=0.1%, New worst char error >> = 9.379 wrote checkpoint. >> >> >> >> Le vendredi 28 juin 2019 17:39:52 UTC+2, shree a écrit : >>> >>> Your best source for documentation is the source code. See >>> >>> >>> https://github.com/tesseract-ocr/tesseract/blob/f522b039a52ae0094fb928ac60a66c4ae0f6c5b9/src/training/lstmtrainer.cpp#L371 >>> >>> >>> >>> https://github.com/tesseract-ocr/tesseract/blob/f522b039a52ae0094fb928ac60a66c4ae0f6c5b9/src/training/lstmtrainer.cpp#L382 >>> >>> >>> On Fri, Jun 28, 2019 at 8:47 PM Arno Loo <arno....@gmail.com> wrote: >>> >>>> I continue to make experiments and trying to understand what seems >>>> important and I have a few questions after a research in Tesseract's wiki >>>> >>>> During the training we can see this kind of information : >>>> At iteration 100/100/100, Mean rms=4.514%, delta=19.089%, char train= >>>> 96.314%, word train=100%, skip ratio=0%, New best char error = 96.314 >>>> wrote checkpoint. >>>> >>>> - *100/100/100 :* What do this 3 numbers at the begining mean when >>>> they are different ? Which they are often, unlike in my example. >>>> - *Mean rms* I know well, it's the Root Mean Square error. But what >>>> error metric is used ? Usually it is some kind of distance, the >>>> Levenshtein >>>> distance is often appropriate for OCR tasks but the "%" wouldn't be there >>>> if it was. >>>> - *delta* I don't know >>>> - *char train *must be the percentage of wrong character predictions >>>> during the *training* >>>> - *word train *must be the percentage of wrong word predictions during >>>> the *training* >>>> - * skip ratio *is I think the percentage of samples skip for any >>>> reason (invalid data or something) >>>> >>>> Does anyone can help me understand them please ? >>>> >>>> Also, I do not see any error on evaluation during the training. Which >>>> would be really helpful to avoid overfitting. The only way I would know >>>> how >>>> to follow the *evaluation* error during the training would be to try a >>>> lstmeval on each checkpoint, but I think there must be a better way ? >>>> Otherwise the *--eval_listfile *argument would be useless in >>>> lstmtraining, but I can't find out how it is used. >>>> >>>> Thank you :) >>>> >>>> Le jeudi 27 juin 2019 19:17:46 UTC+2, shree a écrit : >>>>> >>>>> See >>>>> https://github.com/tesseract-ocr/tesseract/blob/master/doc/lstmeval.1.asc >>>>> >>>>> When using checkpoint you need to also use the starter traineddata >>>>> file used for training. >>>>> >>>>> Or give final traineddata file as model. >>>>> >>>>> So, if after training u have converted the checkpoint to a >>>>> traineddata, you can use that as model. Similarly for the original >>>>> traineddata. >>>>> >>>> -- >>>> You received this message because you are subscribed to the Google >>>> Groups "tesseract-ocr" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to tesser...@googlegroups.com. >>>> To post to this group, send email to tesser...@googlegroups.com. >>>> Visit this group at https://groups.google.com/group/tesseract-ocr. >>>> To view this discussion on the web visit >>>> https://groups.google.com/d/msgid/tesseract-ocr/19f392d5-6d77-4830-93ff-c446d06df6fa%40googlegroups.com >>>> >>>> <https://groups.google.com/d/msgid/tesseract-ocr/19f392d5-6d77-4830-93ff-c446d06df6fa%40googlegroups.com?utm_medium=email&utm_source=footer> >>>> . >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> >>> -- >>> >>> ____________________________________________________________ >>> भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com >>> >> -- >> You received this message because you are subscribed to the Google Groups >> "tesseract-ocr" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to tesser...@googlegroups.com <javascript:>. >> To post to this group, send email to tesser...@googlegroups.com >> <javascript:>. >> Visit this group at https://groups.google.com/group/tesseract-ocr. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/tesseract-ocr/75c48599-79c6-433b-822f-67e909570786%40googlegroups.com >> >> <https://groups.google.com/d/msgid/tesseract-ocr/75c48599-79c6-433b-822f-67e909570786%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> For more options, visit https://groups.google.com/d/optout. >> > > > -- > > ____________________________________________________________ > भजन - कीर्तन - आरती @ http://bhajans.ramparivar.com >
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