opencv/samples/cpp/points_classifier.cpp

#include "opencv2/core/core.hpp"
#include "opencv2/ml/ml.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <stdio.h>

using namespace std;
using namespace cv;

const Scalar WHITE_COLOR = CV_RGB(255,255,255);
const string winName = "points";
const int testStep = 5;


Mat img, img_dst;
RNG rng;

vector<Point>  trainedPoints;
vector<int>    trainedPointsMarkers;
vector<Scalar> classColors;

#define KNN 0
#define SVM 0
#define DT  1
#define RF  0
#define ANN 0
#define GMM 0

void on_mouse( int event, int x, int y, int /*flags*/, void* )
{
    if( img.empty() )
        return;

    int updateFlag = 0;

    if( event == CV_EVENT_LBUTTONUP )
    {
        if( classColors.empty() )
            return;

        trainedPoints.push_back( Point(x,y) );
        trainedPointsMarkers.push_back( classColors.size()-1 );
        updateFlag = true;
    }
    else if( event == CV_EVENT_RBUTTONUP )
    {
        classColors.push_back( Scalar((uchar)rng(256), (uchar)rng(256), (uchar)rng(256)) );
        updateFlag = true;
    }

    //draw
    if( updateFlag )
    {
        img = Scalar::all(0);

        // put the text
        stringstream text;
        text << "current class " << classColors.size()-1;
        putText( img, text.str(), Point(10,25), CV_FONT_HERSHEY_SIMPLEX, 0.8f, WHITE_COLOR, 2 );

        text.str("");
        text << "total classes " << classColors.size();
        putText( img, text.str(), Point(10,50), CV_FONT_HERSHEY_SIMPLEX, 0.8f, WHITE_COLOR, 2 );

        text.str("");
        text << "total points " << trainedPoints.size();
        putText(img, text.str(), cvPoint(10,75), CV_FONT_HERSHEY_SIMPLEX, 0.8f, WHITE_COLOR, 2 );

        // draw points
        for( size_t i = 0; i < trainedPoints.size(); i++ )
            circle( img, trainedPoints[i], 5, classColors[trainedPointsMarkers[i]], -1 );

        imshow( winName, img );
   }
}

void prepare_train_data( Mat& samples, Mat& classes )
{
    Mat( trainedPoints ).copyTo( samples );
    Mat( trainedPointsMarkers ).copyTo( classes );

    // reshape trainData and change its type
    samples = samples.reshape( 1, samples.rows );
    samples.convertTo( samples, CV_32FC1 );
}

#if KNN
void find_decision_boundary_KNN( int K )
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    // learn classifier
    CvKNearest knnClassifier( trainSamples, trainClasses, Mat(), false, K );

    Mat testSample( 1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            int response = (int)knnClassifier.find_nearest( testSample, K );
            circle( img_dst, Point(x,y), 1, classColors[response] );
        }
    }
}
#endif

#if SVM
void find_decision_boundary_SVM( CvSVMParams params )
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    // learn classifier
    CvSVM svmClassifier( trainSamples, trainClasses, Mat(), Mat(), params );

    Mat testSample( 1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            int response = (int)svmClassifier.predict( testSample );
            circle( img_dst, Point(x,y), 2, classColors[response], 1 );
        }
    }


    for( int i = 0; i < svmClassifier.get_support_vector_count(); i++ )
    {
        const float* supportVector = svmClassifier.get_support_vector(i);
        circle( img_dst, Point(supportVector[0],supportVector[1]), 5, CV_RGB(255,255,255), -1 );
    }

}
#endif

#if DT
void find_decision_boundary_DT()
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    // learn classifier
    CvDTree  dtree;

    Mat var_types( 1, trainSamples.cols + 1, CV_8UC1, Scalar(CV_VAR_ORDERED) );
    var_types.at<uchar>( trainSamples.cols ) = CV_VAR_CATEGORICAL;

    CvDTreeParams params;
    params.max_depth = 8;
    params.min_sample_count = 2;
    params.use_surrogates = false;
    params.cv_folds = 0; // the number of cross-validation folds
    params.use_1se_rule = false;
    params.truncate_pruned_tree = false;

    dtree.train( trainSamples, CV_ROW_SAMPLE, trainClasses,
                 Mat(), Mat(), var_types, Mat(), params );

    Mat testSample(1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            int response = (int)dtree.predict( testSample )->value;
            circle( img_dst, Point(x,y), 2, classColors[response], 1 );
        }
    }
}
#endif

#if RF
void find_decision_boundary_RF()
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    // learn classifier
    CvRTrees  rtrees;

    Mat var_types( 1, trainSamples.cols + 1, CV_8UC1, Scalar(CV_VAR_ORDERED) );
    var_types.at<uchar>( trainSamples.cols ) = CV_VAR_CATEGORICAL;

    CvRTParams  params( 4, // max_depth,
                        2, // min_sample_count,
                        0.f, // regression_accuracy,
                        false, // use_surrogates,
                        16, // max_categories,
                        0, // priors,
                        false, // calc_var_importance,
                        1, // nactive_vars,
                        5, // max_num_of_trees_in_the_forest,
                        0, // forest_accuracy,
                        CV_TERMCRIT_ITER // termcrit_type
                       );

    rtrees.train( trainSamples, CV_ROW_SAMPLE, trainClasses, Mat(), Mat(), var_types, Mat(), params );

    Mat testSample(1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            int response = (int)rtrees.predict( testSample );
            circle( img_dst, Point(x,y), 2, classColors[response], 1 );
        }
    }
}

#endif

#if ANN
void find_decision_boundary_ANN( const Mat&  layer_sizes )
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    // prerare trainClasses
    trainClasses.create( trainedPoints.size(), classColors.size(), CV_32FC1 );
    for( int i = 0; i <  trainClasses.rows; i++ )
    {
        for( int k = 0; k < trainClasses.cols; k++ )
        {
            if( k == trainedPointsMarkers[i] )
                trainClasses.at<float>(i,k) = 1;
            else
                trainClasses.at<float>(i,k) = 0;
        }
    }

    Mat weights( 1, trainedPoints.size(), CV_32FC1, Scalar::all(1) );

    // learn classifier
    CvANN_MLP  ann( layer_sizes, CvANN_MLP::SIGMOID_SYM, 1, 1 );
    ann.train( trainSamples, trainClasses, weights );

    Mat testSample( 1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            Mat outputs( 1, classColors.size(), CV_32FC1, testSample.data );
            ann.predict( testSample, outputs );
            Point maxLoc;
            minMaxLoc( outputs, 0, 0, 0, &maxLoc );
            circle( img_dst, Point(x,y), 2, classColors[maxLoc.x], 1 );
        }
    }
}
#endif

#if GMM
void find_decision_boundary_GMM()
{
    img.copyTo( img_dst );

    Mat trainSamples, trainClasses;
    prepare_train_data( trainSamples, trainClasses );

    CvEM em;
    CvEMParams params;
    params.covs      = NULL;
    params.means     = NULL;
    params.weights   = NULL;
    params.probs     = NULL;
    params.nclusters = classColors.size();
    params.cov_mat_type       = CvEM::COV_MAT_GENERIC;
    params.start_step         = CvEM::START_AUTO_STEP;
    params.term_crit.max_iter = 10;
    params.term_crit.epsilon  = 0.1;
    params.term_crit.type     = CV_TERMCRIT_ITER | CV_TERMCRIT_EPS;


    // learn classifier
    em.train( trainSamples, Mat(), params, &trainClasses );

    Mat testSample(1, 2, CV_32FC1 );
    for( int y = 0; y < img.rows; y += testStep )
    {
        for( int x = 0; x < img.cols; x += testStep )
        {
            testSample.at<float>(0) = (float)x;
            testSample.at<float>(1) = (float)y;

            int response = (int)em.predict( testSample );
            circle( img_dst, Point(x,y), 2, classColors[response], 1 );
        }
    }
}
#endif

int main()
{
    cv::namedWindow( "points", 1 );
    img.create( 480, 640, CV_8UC3 );
    img_dst.create( 480, 640, CV_8UC3 );

    imshow( "points", img );
    cvSetMouseCallback( "points", on_mouse );

    for(;;)
    {
        uchar key = waitKey();

        if( key == 27 ) break;

        if( key == 'i' ) // init
        {
            img = Scalar::all(0);

            classColors.clear();
            trainedPoints.clear();
            trainedPointsMarkers.clear();

            imshow( winName, img );
        }

        if( key == 'r' ) // run
        {
#if KNN
            int K = 3;
            find_decision_boundary_KNN( K );
            namedWindow( "kNN", WINDOW_AUTOSIZE );
            imshow( "kNN", img_dst );

            K = 15;
            find_decision_boundary_KNN( K );
            namedWindow( "kNN2", WINDOW_AUTOSIZE );
            imshow( "kNN2", img_dst );
#endif

#if SVM
            //(1)-(2)separable and not sets
            CvSVMParams params;
            params.svm_type = CvSVM::C_SVC;
            params.kernel_type = CvSVM::POLY; //CvSVM::LINEAR;
            params.degree = 0.5;
            params.gamma = 1;
            params.coef0 = 1;
            params.C = 1;
            params.nu = 0.5;
            params.p = 0;
            params.term_crit = cvTermCriteria(CV_TERMCRIT_ITER, 1000, 0.01);

            find_decision_boundary_SVM( params );
            namedWindow( "classificationSVM1", WINDOW_AUTOSIZE );
            imshow( "classificationSVM1", img_dst );

            params.C = 10;
            find_decision_boundary_SVM( params );
            cvNamedWindow( "classificationSVM2", WINDOW_AUTOSIZE );
            imshow( "classificationSVM2", img_dst );
#endif

#if DT
            find_decision_boundary_DT();
            namedWindow( "DT", 1 );
            imshow( "DT", img_dst );
#endif

#if RF
            find_decision_boundary_RF();
            namedWindow( "RF", 1 );
            imshow( "RF", img_dst);
#endif

#if ANN
            Mat layer_sizes1( 1, 3, CV_32SC1 );
            layer_sizes1.at<int>(0) = 2;
            layer_sizes1.at<int>(1) = 5;
            layer_sizes1.at<int>(2) = classColors.size();
            find_decision_boundary_ANN( layer_sizes1 );
            namedWindow( "ANN", WINDOW_AUTOSIZE );
            imshow( "ANN", img_dst );
#endif

#if GMM
            find_decision_boundary_GMM();
            namedWindow( "GMM", WINDOW_AUTOSIZE );
            imshow( "GMM", img_dst );
#endif
        }
    }

    return 1;
}