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Android App don't load SVM trained (on C++) file for recognition

asked 2017-06-07 04:27:42 -0500

sLeo gravatar image

I've trained a svm using OpenCV 3.2 on C++. Just like that

// Set up SVM's parameters
Ptr<SVM> svm = SVM::create();
svm->setType(SVM::C_SVC);
svm->setKernel(SVM::LINEAR);
svm->setC(100);
svm->setTermCriteria(TermCriteria(TermCriteria::MAX_ITER, 100, 1e-6));

// Train the SVM with given parameters
Ptr<TrainData> td = TrainData::create(training_mat, ROW_SAMPLE, labelsMat);
svm->train(td);
svm->save("images/svm_filename.xml");

Now I try to load the produced xml file on Android, I use the OpenCV4Android (OpenCV 3.2). But the load function seems not to work. the load function SVM svm = SVM.load("svm_filename.xml"); just throws an exception (the path is correct because I included the xml file in the App).

cv::Exception: /build/master_pack-android/opencv/modules/ml/src/svm.cpp:2123: error: (-212) Missing or invalid SVM type in function void cv::ml::SVMImpl::read_params(const cv::FileNode&)

On C++ everything's fine, the load function works fine

svm->load("images/svm_filename.xml");

I don't understand why the svm type is mentioned as missing. When I take a look a the XML file the svm type is C_SVC. here is a part of the xmlimage description

I don't know what I miss.

can someone please help me?

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svm->load("images/svm_filename.xml"); this is wrong, and won't do anything useful. please use:

Ptr<SVM> svm = StatModel::load>SVM>("my.xml");

(it's a static function, which returns a new object)

berak gravatar imageberak ( 2017-06-07 23:37:26 -0500 )edit

@berak I'm the one who post the question but I can't sign in with sleo, that's why I create a new user account.

svm->load("images/svm_filename.xml");

the function is working fine and gives satisfying result in C++. but I want to load the xml file in Android like this

SVM svm = SVM.load("svm_filename.xml")

using the OpenCV4Android library (OpenCV 3.2)

sleo5 gravatar imagesleo5 ( 2017-06-08 17:19:23 -0500 )edit

if you think, we can help with your account problem: issue here

can it be, your c++ and java versions are slightly "out-of-sync" and disagree, where to look for e.g. the svm type in the xml ? (there were bugs/changes in early 3.2 there)

would updating the src code, and building the android wrappers locally be an option for you ?

berak gravatar imageberak ( 2017-06-08 22:49:03 -0500 )edit

@sleo5 finally how you load xml?

jikolp95 gravatar imagejikolp95 ( 2018-03-07 06:24:10 -0500 )edit

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answered 2018-02-24 02:39:31 -0500

Ramir gravatar image

svm->save("images/svm_filename.xml");

It might be the path. The path should be

svm->save(""/storage/emulated/0/images/svm_filename.xml");

or

svm->save(""/storage/emulated/1/images/svm_filename.xml");

if you are using external directory.

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imho, you misread it. the svm was trained (and saved) on a desktop pc, not android

berak gravatar imageberak ( 2018-02-24 02:47:07 -0500 )edit
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Asked: 2017-06-07 04:27:42 -0500

Seen: 954 times

Last updated: Feb 24 '18