Opencv 3 SVM training

c++, machine-learning, opencv, opencv3.0, svm

Solution

with opencv3.0, it's definitely different , but not difficult:

Ptr<ml::SVM> svm = ml::SVM::create();
// edit: the params struct got removed,
// we use setter/getter now:
svm->setType(ml::SVM::C_SVC);
svm->setKernel(ml::SVM::POLY);
svm->setGamma(3); 

Mat trainData; // one row per feature
Mat labels;    
svm->train( trainData , ml::ROW_SAMPLE , labels );
// ...
Mat query; // input, 1channel, 1 row (apply reshape(1,1) if nessecary)
Mat res;   // output
svm->predict(query, res);

Problem

As you may know, many things changed in OpenCV 3 (in comparision to the openCV2 or the old first version). In the old days, to train SVM one would use: ``` CvSVMParams params; params.svm_type = CvSVM::C_SVC; params.kernel_type = CvSVM::POLY; params.gamma = 3; CvSVM svm; svm.train(training_mat, labels, Mat(), Mat(), params); ``` In the third version of API, there is no `CvSVMParams` nor `CvSVM`. Surprisingly, there is a documentation page about SVM, but it tells everything, but not how to really use it (at least I cannot make it out). Moreover, it looks like no one in the Internet uses SVM from OpenCV's 3.0. Currently, I only managed to get the following: ``` ml::SVM.Params params; params.svmType = ml::SVM::C_SVC; params.kernelType = ml::SVM::POLY; params.gamma = 3; ``` Can you please provide me with information, how to rewrite the actual training to openCV 3?

Original source