OpenCV 3 KNN Character Recognition C++

GitHub site:

Prerequisite:

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[akbare-z]

quick and nice explanation as always sir.

[jingyugao]

I wonder why it creates a blank "classifications.xml" and "images.xml" after I do the DataGen.cpp

[andreasas]

thanks dude, your tutorial is too good ^_^

[valizeth]

KNN? Kohnen neural network? Wouldn't hopfield be a better structure?

[djalmasilva]

How can we put a new symbol for recognition in that package?

[amrahmed]

Thank you for such a tutorial, but i wonder how we can train such a model? to read different plates?

[MirabaBR]

+Chris Dahms
Hi Chris,
One comment: I went through all four videos and practical tasks on OpenCV 3 Win 10 install, then came directly to this video. It just so happens that, at the end of Part 4, Path environment variable has the "mybuild" dir on it. Due to that, running GenData got me an error not finding opencv_world310d.lib, even though include/libraries/input dirs were properly set. So I had to go back and set Path with again. Just to let you know, perhaps other might face the same problem.
Best regards.

[seimkeim]

Hi, I'm trying to detect letters in an up-scaled screenshot. The letters aren't sharp anymore. Is it possible to use non-sharp letters as training set to detect them non-sharp letters?

[unknowmember]

How can I fix the "Operation not supported. Unknow error" ?

[mohamedbouacheria]

hello and thank you very much, this was very helpful, but do you have an idea how to do the inverse, mean you enter a character and and the program finds it in the image ?

[lilyz.]

Thanks for your tutorial, and I am working on some realtime character recognition code, and I kept runing into bugs. So I am wondering if you are planing to do some realtime detection project, or if you know any tutorials available?

[andreitomut]

Thank you a lot for tutorilal ! Great Job !

[coders]

cv::waitKey(0) or cv::waitKeyEx(0) can not read utf8 char
how to read UTF char?

[joshuamzm]

Very nice tutorial! Just a question, how performant is the KNN algorithm on recognizing the characters in your tests?

[vickybangalore]

Hai Chris can you help me with the extraction of geo-spatial data (latitude and longitude )associated with the images, so that image is matched according to their location.

[fedibenkhalifa]

hi chris, i get an empty XML file when i executed getdata on ubuntu pls help !!!

[andre]

Hi, Very good example!!! But I having this error: OpenCV Error: Assertion failed (samples.type() == CV_32F || samples.type() == CV_32S) in cv::ml::TrainDataImpl::setData, file C:\buildslave64\win64_amdocl\master_PackSlave-win64-vc14-shared\opencv\modules\ml\src\data.cpp, line 251
I just get the sample code to see the program working, but in my computer with VS2015 and OpenCV 3.1 this error appear when I try to execute the TrainAndTest.cpp. Could you help me?

[dayanthailangasinghe]

Great Tutorial. thanks a lot. Btw is there any tutorial regarding SVM classification which i could refer?

[fud]

Thank you for tutorial but
I got error "OpenCV Error: Assertion failed (samples.type() == CV_32F || samples.type() == CV_32S) "
I run on opencv3.2.0 visual studio 2015 how can I resolve it ?

[ManojKumar-tikn]

Which feature descriptor ((Like:--Principal component analysis, , HOG, , Linear discriminant Analysis)) you have used before classifying charecters using KNN??