test_arucodetection.cpp

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#include "test_precomp.hpp"
#include <opencv2/aruco.hpp>
#include <string>

using namespace std;
using namespace cv;


/**
 * @brief Draw 2D synthetic markers and detect them
 */
class CV_ArucoDetectionSimple : public cvtest::BaseTest {
    public:
    CV_ArucoDetectionSimple();

    protected:
    void run(int);
};


CV_ArucoDetectionSimple::CV_ArucoDetectionSimple() {}


void CV_ArucoDetectionSimple::run(int) {

    aruco::Dictionary dictionary = aruco::getPredefinedDictionary(aruco::DICT_6X6_250);

    // 20 images
    for(int i = 0; i < 20; i++) {

        const int markerSidePixels = 100;
        int imageSize = markerSidePixels * 2 + 3 * (markerSidePixels / 2);

        // draw synthetic image and store marker corners and ids
        vector< vector< Point2f > > groundTruthCorners;
        vector< int > groundTruthIds;
        Mat img = Mat(imageSize, imageSize, CV_8UC1, Scalar::all(255));
        for(int y = 0; y < 2; y++) {
            for(int x = 0; x < 2; x++) {
                Mat marker;
                int id = i * 4 + y * 2 + x;
                aruco::drawMarker(dictionary, id, markerSidePixels, marker);
                Point2f firstCorner =
                    Point2f(markerSidePixels / 2.f + x * (1.5f * markerSidePixels),
                            markerSidePixels / 2.f + y * (1.5f * markerSidePixels));
                Mat aux = img.colRange((int)firstCorner.x, (int)firstCorner.x + markerSidePixels)
                              .rowRange((int)firstCorner.y, (int)firstCorner.y + markerSidePixels);
                marker.copyTo(aux);
                groundTruthIds.push_back(id);
                groundTruthCorners.push_back(vector< Point2f >());
                groundTruthCorners.back().push_back(firstCorner);
                groundTruthCorners.back().push_back(firstCorner + Point2f(markerSidePixels - 1, 0));
                groundTruthCorners.back().push_back(
                    firstCorner + Point2f(markerSidePixels - 1, markerSidePixels - 1));
                groundTruthCorners.back().push_back(firstCorner + Point2f(0, markerSidePixels - 1));
            }
        }
        if(i % 2 == 1) img.convertTo(img, CV_8UC3);

        // detect markers
        vector< vector< Point2f > > corners;
        vector< int > ids;
        aruco::DetectorParameters params;
        aruco::detectMarkers(img, dictionary, corners, ids, params);

        // check detection results
        for(unsigned int m = 0; m < groundTruthIds.size(); m++) {
            int idx = -1;
            for(unsigned int k = 0; k < ids.size(); k++) {
                if(groundTruthIds[m] == ids[k]) {
                    idx = (int)k;
                    break;
                }
            }
            if(idx == -1) {
                ts->printf(cvtest::TS::LOG, "Marker not detected");
                ts->set_failed_test_info(cvtest::TS::FAIL_MISMATCH);
                return;
            }

            for(int c = 0; c < 4; c++) {
                double dist = norm(groundTruthCorners[m][c] - corners[idx][c]);
                if(dist > 0.001) {
                    ts->printf(cvtest::TS::LOG, "Incorrect marker corners position");
                    ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
                    return;
                }
            }
        }
    }
}


static double deg2rad(double deg) { return deg * CV_PI / 180.; }

/**
 * @brief Get rvec and tvec from yaw, pitch and distance
 */
static void getSyntheticRT(double yaw, double pitch, double distance, Mat &rvec, Mat &tvec) {

    rvec = Mat(3, 1, CV_64FC1);
    tvec = Mat(3, 1, CV_64FC1);

    // Rvec
    // first put the Z axis aiming to -X (like the camera axis system)
    Mat rotZ(3, 1, CV_64FC1);
    rotZ.ptr< double >(0)[0] = 0;
    rotZ.ptr< double >(0)[1] = 0;
    rotZ.ptr< double >(0)[2] = -0.5 * CV_PI;

    Mat rotX(3, 1, CV_64FC1);
    rotX.ptr< double >(0)[0] = 0.5 * CV_PI;
    rotX.ptr< double >(0)[1] = 0;
    rotX.ptr< double >(0)[2] = 0;

    Mat camRvec, camTvec;
    composeRT(rotZ, Mat(3, 1, CV_64FC1, Scalar::all(0)), rotX, Mat(3, 1, CV_64FC1, Scalar::all(0)),
              camRvec, camTvec);

    // now pitch and yaw angles
    Mat rotPitch(3, 1, CV_64FC1);
    rotPitch.ptr< double >(0)[0] = 0;
    rotPitch.ptr< double >(0)[1] = pitch;
    rotPitch.ptr< double >(0)[2] = 0;

    Mat rotYaw(3, 1, CV_64FC1);
    rotYaw.ptr< double >(0)[0] = yaw;
    rotYaw.ptr< double >(0)[1] = 0;
    rotYaw.ptr< double >(0)[2] = 0;

    composeRT(rotPitch, Mat(3, 1, CV_64FC1, Scalar::all(0)), rotYaw,
              Mat(3, 1, CV_64FC1, Scalar::all(0)), rvec, tvec);

    // compose both rotations
    composeRT(camRvec, Mat(3, 1, CV_64FC1, Scalar::all(0)), rvec,
              Mat(3, 1, CV_64FC1, Scalar::all(0)), rvec, tvec);

    // Tvec, just move in z (camera) direction the specific distance
    tvec.ptr< double >(0)[0] = 0.;
    tvec.ptr< double >(0)[1] = 0.;
    tvec.ptr< double >(0)[2] = distance;
}

/**
 * @brief Create a synthetic image of a marker with perspective
 */
static Mat projectMarker(aruco::Dictionary dictionary, int id, Mat cameraMatrix, double yaw,
                         double pitch, double distance, Size imageSize, int markerBorder,
                         vector< Point2f > &corners) {

    // canonical image
    Mat markerImg;
    const int markerSizePixels = 100;
    aruco::drawMarker(dictionary, id, markerSizePixels, markerImg, markerBorder);

    // get rvec and tvec for the perspective
    Mat rvec, tvec;
    getSyntheticRT(yaw, pitch, distance, rvec, tvec);

    const float markerLength = 0.05f;
    vector< Point3f > markerObjPoints;
    markerObjPoints.push_back(Point3f(-markerLength / 2.f, +markerLength / 2.f, 0));
    markerObjPoints.push_back(markerObjPoints[0] + Point3f(markerLength, 0, 0));
    markerObjPoints.push_back(markerObjPoints[0] + Point3f(markerLength, -markerLength, 0));
    markerObjPoints.push_back(markerObjPoints[0] + Point3f(0, -markerLength, 0));

    // project markers and draw them
    Mat distCoeffs(5, 1, CV_64FC1, Scalar::all(0));
    projectPoints(markerObjPoints, rvec, tvec, cameraMatrix, distCoeffs, corners);

    vector< Point2f > originalCorners;
    originalCorners.push_back(Point2f(0, 0));
    originalCorners.push_back(Point2f((float)markerSizePixels, 0));
    originalCorners.push_back(Point2f((float)markerSizePixels, (float)markerSizePixels));
    originalCorners.push_back(Point2f(0, (float)markerSizePixels));

    Mat transformation = getPerspectiveTransform(originalCorners, corners);

    Mat img(imageSize, CV_8UC1, Scalar::all(255));
    Mat aux;
    const char borderValue = 127;
    warpPerspective(markerImg, aux, transformation, imageSize, INTER_NEAREST, BORDER_CONSTANT,
                    Scalar::all(borderValue));

    // copy only not-border pixels
    for(int y = 0; y < aux.rows; y++) {
        for(int x = 0; x < aux.cols; x++) {
            if(aux.at< unsigned char >(y, x) == borderValue) continue;
            img.at< unsigned char >(y, x) = aux.at< unsigned char >(y, x);
        }
    }

    return img;
}



/**
 * @brief Draws markers in perspective and detect them
 */
class CV_ArucoDetectionPerspective : public cvtest::BaseTest {
    public:
    CV_ArucoDetectionPerspective();

    protected:
    void run(int);
};


CV_ArucoDetectionPerspective::CV_ArucoDetectionPerspective() {}


void CV_ArucoDetectionPerspective::run(int) {

    int iter = 0;
    Mat cameraMatrix = Mat::eye(3, 3, CV_64FC1);
    Size imgSize(500, 500);
    cameraMatrix.at< double >(0, 0) = cameraMatrix.at< double >(1, 1) = 650;
    cameraMatrix.at< double >(0, 2) = imgSize.width / 2;
    cameraMatrix.at< double >(1, 2) = imgSize.height / 2;
    aruco::Dictionary dictionary = aruco::getPredefinedDictionary(aruco::DICT_6X6_250);

    // detect from different positions
    for(double distance = 0.1; distance <= 0.5; distance += 0.2) {
        for(int pitch = 0; pitch < 360; pitch += 60) {
            for(int yaw = 30; yaw <= 90; yaw += 50) {
                int currentId = iter % 250;
                int markerBorder = iter % 2 + 1;
                iter++;
                vector< Point2f > groundTruthCorners;
                // create synthetic image
                Mat img =
                    projectMarker(dictionary, currentId, cameraMatrix, deg2rad(yaw), deg2rad(pitch),
                                  distance, imgSize, markerBorder, groundTruthCorners);

                // detect markers
                vector< vector< Point2f > > corners;
                vector< int > ids;
                aruco::DetectorParameters params;
                params.minDistanceToBorder = 1;
                params.markerBorderBits = markerBorder;
                aruco::detectMarkers(img, dictionary, corners, ids, params);

                // check results
                if(ids.size() != 1 || (ids.size() == 1 && ids[0] != currentId)) {
                    if(ids.size() != 1)
                        ts->printf(cvtest::TS::LOG, "Incorrect number of detected markers");
                    else
                        ts->printf(cvtest::TS::LOG, "Incorrect marker id");
                    ts->set_failed_test_info(cvtest::TS::FAIL_MISMATCH);
                    return;
                }
                for(int c = 0; c < 4; c++) {
                    double dist = norm(groundTruthCorners[c] - corners[0][c]);
                    if(dist > 5) {
                        ts->printf(cvtest::TS::LOG, "Incorrect marker corners position");
                        ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
                        return;
                    }
                }
            }
        }
    }
}


/**
 * @brief Check max and min size in marker detection parameters
 */
class CV_ArucoDetectionMarkerSize : public cvtest::BaseTest {
    public:
    CV_ArucoDetectionMarkerSize();

    protected:
    void run(int);
};


CV_ArucoDetectionMarkerSize::CV_ArucoDetectionMarkerSize() {}


void CV_ArucoDetectionMarkerSize::run(int) {

    aruco::Dictionary dictionary = aruco::getPredefinedDictionary(aruco::DICT_6X6_250);
    int markerSide = 20;
    int imageSize = 200;

    // 10 cases
    for(int i = 0; i < 10; i++) {
        Mat marker;
        int id = 10 + i * 20;

        // create synthetic image
        Mat img = Mat(imageSize, imageSize, CV_8UC1, Scalar::all(255));
        aruco::drawMarker(dictionary, id, markerSide, marker);
        Mat aux = img.colRange(30, 30 + markerSide).rowRange(50, 50 + markerSide);
        marker.copyTo(aux);

        vector< vector< Point2f > > corners;
        vector< int > ids;
        aruco::DetectorParameters params;

        // set a invalid minMarkerPerimeterRate
        params.minMarkerPerimeterRate = min(4., (4. * markerSide) / float(imageSize) + 0.1);
        aruco::detectMarkers(img, dictionary, corners, ids, params);
        if(corners.size() != 0) {
            ts->printf(cvtest::TS::LOG, "Error in DetectorParameters::minMarkerPerimeterRate");
            ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
            return;
        }

        // set an valid minMarkerPerimeterRate
        params.minMarkerPerimeterRate = max(0., (4. * markerSide) / float(imageSize) - 0.1);
        aruco::detectMarkers(img, dictionary, corners, ids, params);
        if(corners.size() != 1 || (corners.size() == 1 && ids[0] != id)) {
            ts->printf(cvtest::TS::LOG, "Error in DetectorParameters::minMarkerPerimeterRate");
            ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
            return;
        }

        // set a invalid maxMarkerPerimeterRate
        params.maxMarkerPerimeterRate = min(4., (4. * markerSide) / float(imageSize) - 0.1);
        aruco::detectMarkers(img, dictionary, corners, ids, params);
        if(corners.size() != 0) {
            ts->printf(cvtest::TS::LOG, "Error in DetectorParameters::maxMarkerPerimeterRate");
            ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
            return;
        }

        // set an valid maxMarkerPerimeterRate
        params.maxMarkerPerimeterRate = max(0., (4. * markerSide) / float(imageSize) + 0.1);
        aruco::detectMarkers(img, dictionary, corners, ids, params);
        if(corners.size() != 1 || (corners.size() == 1 && ids[0] != id)) {
            ts->printf(cvtest::TS::LOG, "Error in DetectorParameters::maxMarkerPerimeterRate");
            ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
            return;
        }
    }
}


/**
 * @brief Check error correction in marker bits
 */
class CV_ArucoBitCorrection : public cvtest::BaseTest {
    public:
    CV_ArucoBitCorrection();

    protected:
    void run(int);
};


CV_ArucoBitCorrection::CV_ArucoBitCorrection() {}


void CV_ArucoBitCorrection::run(int) {

    aruco::Dictionary dictionary = aruco::getPredefinedDictionary(aruco::DICT_6X6_250);
    aruco::Dictionary dictionary2 = dictionary;
    int markerSide = 50;
    int imageSize = 150;
    aruco::DetectorParameters params;

    // 10 markers
    for(int l = 0; l < 10; l++) {
        Mat marker;
        int id = 10 + l * 20;

        Mat currentCodeBytes = dictionary.bytesList.rowRange(id, id + 1);

        // 5 valid cases
        for(int i = 0; i < 5; i++) {
            // how many bit errors (the error is low enough so it can be corrected)
            params.errorCorrectionRate = 0.2 + i * 0.1;
            int errors =
                (int)std::floor(dictionary.maxCorrectionBits * params.errorCorrectionRate - 1.);

            // create erroneous marker in currentCodeBits
            Mat currentCodeBits =
                aruco::Dictionary::getBitsFromByteList(currentCodeBytes, dictionary.markerSize);
            for(int e = 0; e < errors; e++) {
                currentCodeBits.ptr< unsigned char >()[2 * e] =
                    !currentCodeBits.ptr< unsigned char >()[2 * e];
            }

            // add erroneous marker to dictionary2 in order to create the erroneous marker image
            Mat currentCodeBytesError = aruco::Dictionary::getByteListFromBits(currentCodeBits);
            currentCodeBytesError.copyTo(dictionary2.bytesList.rowRange(id, id + 1));
            Mat img = Mat(imageSize, imageSize, CV_8UC1, Scalar::all(255));
            aruco::drawMarker(dictionary2, id, markerSide, marker);
            Mat aux = img.colRange(30, 30 + markerSide).rowRange(50, 50 + markerSide);
            marker.copyTo(aux);

            // try to detect using original dictionary
            vector< vector< Point2f > > corners;
            vector< int > ids;
            aruco::detectMarkers(img, dictionary, corners, ids, params);
            if(corners.size() != 1 || (corners.size() == 1 && ids[0] != id)) {
                ts->printf(cvtest::TS::LOG, "Error in bit correction");
                ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
                return;
            }
        }

        // 5 invalid cases
        for(int i = 0; i < 5; i++) {
            // how many bit errors (the error is too high to be corrected)
            params.errorCorrectionRate = 0.2 + i * 0.1;
            int errors =
                (int)std::floor(dictionary.maxCorrectionBits * params.errorCorrectionRate + 1.);

            // create erroneous marker in currentCodeBits
            Mat currentCodeBits =
                aruco::Dictionary::getBitsFromByteList(currentCodeBytes, dictionary.markerSize);
            for(int e = 0; e < errors; e++) {
                currentCodeBits.ptr< unsigned char >()[2 * e] =
                    !currentCodeBits.ptr< unsigned char >()[2 * e];
            }

            // dictionary3 is only composed by the modified marker (in its original form)
            aruco::Dictionary dictionary3 = dictionary;
            dictionary3.bytesList = dictionary2.bytesList.rowRange(id, id + 1).clone();

            // add erroneous marker to dictionary2 in order to create the erroneous marker image
            Mat currentCodeBytesError = aruco::Dictionary::getByteListFromBits(currentCodeBits);
            currentCodeBytesError.copyTo(dictionary2.bytesList.rowRange(id, id + 1));
            Mat img = Mat(imageSize, imageSize, CV_8UC1, Scalar::all(255));
            aruco::drawMarker(dictionary2, id, markerSide, marker);
            Mat aux = img.colRange(30, 30 + markerSide).rowRange(50, 50 + markerSide);
            marker.copyTo(aux);

            // try to detect using dictionary3, it should fail
            vector< vector< Point2f > > corners;
            vector< int > ids;
            aruco::detectMarkers(img, dictionary3, corners, ids, params);
            if(corners.size() != 0) {
                ts->printf(cvtest::TS::LOG, "Error in DetectorParameters::errorCorrectionRate");
                ts->set_failed_test_info(cvtest::TS::FAIL_BAD_ACCURACY);
                return;
            }
        }
    }
}




TEST(CV_ArucoDetectionSimple, algorithmic) {
    CV_ArucoDetectionSimple test;
    test.safe_run();
}

TEST(CV_ArucoDetectionPerspective, algorithmic) {
    CV_ArucoDetectionPerspective test;
    test.safe_run();
}

TEST(CV_ArucoDetectionMarkerSize, algorithmic) {
    CV_ArucoDetectionMarkerSize test;
    test.safe_run();
}

TEST(CV_ArucoBitCorrection, algorithmic) {
    CV_ArucoBitCorrection test;
    test.safe_run();
}