opencv/modules/calib3d/test/test_cornerssubpix.cpp

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#include "test_precomp.hpp"
#include <limits>
#include "test_chessboardgenerator.hpp"

using namespace cv;

class CV_ChessboardSubpixelTest : public cvtest::BaseTest
{
public:
    CV_ChessboardSubpixelTest();

protected:
    Mat intrinsic_matrix_;
    Mat distortion_coeffs_;
    Size image_size_;

    void run(int);
    void generateIntrinsicParams();
};


int calcDistance(const vector<Point2f>& set1, const vector<Point2f>& set2, double& mean_dist)
{
    if(set1.size() != set2.size())
    {
        return 0;
    }

    std::vector<int> indices;
    double sum_dist = 0.0;
    for(size_t i = 0; i < set1.size(); i++)
    {
        double min_dist = std::numeric_limits<double>::max();
        int min_idx = -1;

        for(int j = 0; j < (int)set2.size(); j++)
        {
            double dist = norm(set1[i] - set2[j]);
            if(dist < min_dist)
            {
                min_idx = j;
                min_dist = dist;
            }
        }

        // check validity of min_idx
        if(min_idx == -1)
        {
            return 0;
        }
        std::vector<int>::iterator it = std::find(indices.begin(), indices.end(), min_idx);
        if(it != indices.end())
        {
            // there are two points in set1 corresponding to the same point in set2
            return 0;
        }
        indices.push_back(min_idx);

//        printf("dist %d = %f\n", (int)i, min_dist);

        sum_dist += min_dist*min_dist;
    }

    mean_dist = sqrt(sum_dist/set1.size());
//    printf("sum_dist = %f, set1.size() = %d, mean_dist = %f\n", sum_dist, (int)set1.size(), mean_dist);

    return 1;
}

CV_ChessboardSubpixelTest::CV_ChessboardSubpixelTest() :
    intrinsic_matrix_(Size(3, 3), CV_64FC1), distortion_coeffs_(Size(1, 4), CV_64FC1),
    image_size_(640, 480)
{
}

/* ///////////////////// chess_corner_test ///////////////////////// */
void CV_ChessboardSubpixelTest::run( int )
{
    int code = cvtest::TS::OK;
    int  progress = 0;

    RNG& rng = ts->get_rng();

    const int runs_count = 20;
    const int max_pattern_size = 8;
    const int min_pattern_size = 5;
    Mat bg(image_size_, CV_8UC1);
    bg = Scalar(0);

    double sum_dist = 0.0;
    int count = 0;
    for(int i = 0; i < runs_count; i++)
    {
        const int pattern_width = min_pattern_size + cvtest::randInt(rng) % (max_pattern_size - min_pattern_size);
        const int pattern_height = min_pattern_size + cvtest::randInt(rng) % (max_pattern_size - min_pattern_size);
        Size pattern_size;
        if(pattern_width > pattern_height)
        {
            pattern_size = Size(pattern_height, pattern_width);
        }
        else
        {
            pattern_size = Size(pattern_width, pattern_height);
        }
        ChessBoardGenerator gen_chessboard(Size(pattern_size.width + 1, pattern_size.height + 1));

        // generates intrinsic camera and distortion matrices
        generateIntrinsicParams();

        vector<Point2f> corners;
        Mat chessboard_image = gen_chessboard(bg, intrinsic_matrix_, distortion_coeffs_, corners);

        vector<Point2f> test_corners;
        bool result = findChessboardCorners(chessboard_image, pattern_size, test_corners, 15);
        if(!result)
        {
#if 0
            ts->printf(cvtest::TS::LOG, "Warning: chessboard was not detected! Writing image to test.png\n");
            ts->printf(cvtest::TS::LOG, "Size = %d, %d\n", pattern_size.width, pattern_size.height);
            ts->printf(cvtest::TS::LOG, "Intrinsic params: fx = %f, fy = %f, cx = %f, cy = %f\n",
                       intrinsic_matrix_.at<double>(0, 0), intrinsic_matrix_.at<double>(1, 1),
                       intrinsic_matrix_.at<double>(0, 2), intrinsic_matrix_.at<double>(1, 2));
            ts->printf(cvtest::TS::LOG, "Distortion matrix: %f, %f, %f, %f, %f\n",
                       distortion_coeffs_.at<double>(0, 0), distortion_coeffs_.at<double>(0, 1),
                       distortion_coeffs_.at<double>(0, 2), distortion_coeffs_.at<double>(0, 3),
                       distortion_coeffs_.at<double>(0, 4));

            imwrite("test.png", chessboard_image);
#endif
            continue;
        }

        double dist1 = 0.0;
        int ret = calcDistance(corners, test_corners, dist1);
        if(ret == 0)
        {
            ts->printf(cvtest::TS::LOG, "findChessboardCorners returns invalid corner coordinates!\n");
            code = cvtest::TS::FAIL_INVALID_OUTPUT;
            break;
        }

        IplImage chessboard_image_header = chessboard_image;
        cvFindCornerSubPix(&chessboard_image_header, (CvPoint2D32f*)&test_corners[0],
            (int)test_corners.size(), cvSize(3, 3), cvSize(1, 1), cvTermCriteria(CV_TERMCRIT_EPS|CV_TERMCRIT_ITER,300,0.1));
        find4QuadCornerSubpix(chessboard_image, test_corners, Size(5, 5));

        double dist2 = 0.0;
        ret = calcDistance(corners, test_corners, dist2);
        if(ret == 0)
        {
            ts->printf(cvtest::TS::LOG, "findCornerSubpix returns invalid corner coordinates!\n");
            code = cvtest::TS::FAIL_INVALID_OUTPUT;
            break;
        }

        ts->printf(cvtest::TS::LOG, "Error after findChessboardCorners: %f, after findCornerSubPix: %f\n",
                   dist1, dist2);
        sum_dist += dist2;
        count++;

        const double max_reduce_factor = 0.8;
        if(dist1 < dist2*max_reduce_factor)
        {
            ts->printf(cvtest::TS::LOG, "findCornerSubPix increases average error!\n");
            code = cvtest::TS::FAIL_INVALID_OUTPUT;
            break;
        }

        progress = update_progress( progress, i-1, runs_count, 0 );
    }
    sum_dist /= count;
    ts->printf(cvtest::TS::LOG, "Average error after findCornerSubpix: %f\n", sum_dist);

    if( code < 0 )
        ts->set_failed_test_info( code );
}

void CV_ChessboardSubpixelTest::generateIntrinsicParams()
{
    RNG& rng = ts->get_rng();
    const double max_focus_length = 1000.0;
    const double max_focus_diff = 5.0;

    double fx = cvtest::randReal(rng)*max_focus_length;
    double fy = fx + cvtest::randReal(rng)*max_focus_diff;
    double cx = image_size_.width/2;
    double cy = image_size_.height/2;

    double k1 = 0.5*cvtest::randReal(rng);
    double k2 = 0.05*cvtest::randReal(rng);
    double p1 = 0.05*cvtest::randReal(rng);
    double p2 = 0.05*cvtest::randReal(rng);
    double k3 = 0.0;

    intrinsic_matrix_ = (Mat_<double>(3, 3) << fx, 0.0, cx, 0.0, fy, cy, 0.0, 0.0, 1.0);
    distortion_coeffs_ = (Mat_<double>(1, 5) << k1, k2, p1, p2, k3);
}

TEST(Calib3d_ChessboardSubPixDetector, accuracy) { CV_ChessboardSubpixelTest test; test.safe_run(); }

/* End of file. */