OpenCV/opencv_contrib/modules/aruco/samples/calibrate_camera_charuco.cpp

/*
By downloading, copying, installing or using the software you agree to this
license. If you do not agree to this license, do not download, install,
copy or use the software.

                          License Agreement
               For Open Source Computer Vision Library
                       (3-clause BSD License)

Copyright (C) 2013, OpenCV Foundation, all rights reserved.
Third party copyrights are property of their respective owners.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

  * Redistributions of source code must retain the above copyright notice,
    this list of conditions and the following disclaimer.

  * Redistributions in binary form must reproduce the above copyright notice,
    this list of conditions and the following disclaimer in the documentation
    and/or other materials provided with the distribution.

  * Neither the names of the copyright holders nor the names of the contributors
    may be used to endorse or promote products derived from this software
    without specific prior written permission.

This software is provided by the copyright holders and contributors "as is" and
any express or implied warranties, including, but not limited to, the implied
warranties of merchantability and fitness for a particular purpose are
disclaimed. In no event shall copyright holders or contributors be liable for
any direct, indirect, incidental, special, exemplary, or consequential damages
(including, but not limited to, procurement of substitute goods or services;
loss of use, data, or profits; or business interruption) however caused
and on any theory of liability, whether in contract, strict liability,
or tort (including negligence or otherwise) arising in any way out of
the use of this software, even if advised of the possibility of such damage.
*/


#include <opencv2/highgui.hpp>
#include <opencv2/calib3d.hpp>
#include <opencv2/aruco/charuco.hpp>
#include <opencv2/imgproc.hpp>
#include <vector>
#include <iostream>
#include "aruco_samples_utility.hpp"

using namespace std;
using namespace cv;

namespace {
const char* about =
        "Calibration using a ChArUco board\n"
        "  To capture a frame for calibration, press 'c',\n"
        "  If input comes from video, press any key for next frame\n"
        "  To finish capturing, press 'ESC' key and calibration starts.\n";
const char* keys  =
        "{w        |       | Number of squares in X direction }"
        "{h        |       | Number of squares in Y direction }"
        "{sl       |       | Square side length (in meters) }"
        "{ml       |       | Marker side length (in meters) }"
        "{d        |       | dictionary: DICT_4X4_50=0, DICT_4X4_100=1, DICT_4X4_250=2,"
        "DICT_4X4_1000=3, DICT_5X5_50=4, DICT_5X5_100=5, DICT_5X5_250=6, DICT_5X5_1000=7, "
        "DICT_6X6_50=8, DICT_6X6_100=9, DICT_6X6_250=10, DICT_6X6_1000=11, DICT_7X7_50=12,"
        "DICT_7X7_100=13, DICT_7X7_250=14, DICT_7X7_1000=15, DICT_ARUCO_ORIGINAL = 16}"
        "{cd       |       | Input file with custom dictionary }"
        "{@outfile |<none> | Output file with calibrated camera parameters }"
        "{v        |       | Input from video file, if ommited, input comes from camera }"
        "{ci       | 0     | Camera id if input doesnt come from video (-v) }"
        "{dp       |       | File of marker detector parameters }"
        "{rs       | false | Apply refind strategy }"
        "{zt       | false | Assume zero tangential distortion }"
        "{a        |       | Fix aspect ratio (fx/fy) to this value }"
        "{pc       | false | Fix the principal point at the center }"
        "{sc       | false | Show detected chessboard corners after calibration }";
}


int main(int argc, char *argv[]) {
    CommandLineParser parser(argc, argv, keys);
    parser.about(about);

    if(argc < 7) {
        parser.printMessage();
        return 0;
    }

    int squaresX = parser.get<int>("w");
    int squaresY = parser.get<int>("h");
    float squareLength = parser.get<float>("sl");
    float markerLength = parser.get<float>("ml");
    string outputFile = parser.get<string>(0);

    bool showChessboardCorners = parser.get<bool>("sc");

    int calibrationFlags = 0;
    float aspectRatio = 1;
    if(parser.has("a")) {
        calibrationFlags |= CALIB_FIX_ASPECT_RATIO;
        aspectRatio = parser.get<float>("a");
    }
    if(parser.get<bool>("zt")) calibrationFlags |= CALIB_ZERO_TANGENT_DIST;
    if(parser.get<bool>("pc")) calibrationFlags |= CALIB_FIX_PRINCIPAL_POINT;

    Ptr<aruco::DetectorParameters> detectorParams;
    if(parser.has("dp")) {
        FileStorage fs(parser.get<string>("dp"), FileStorage::READ);
        bool readOk = aruco::DetectorParameters::readDetectorParameters(fs.root(), detectorParams);
        if(!readOk) {
            cerr << "Invalid detector parameters file" << endl;
            return 0;
        }
    }

    bool refindStrategy = parser.get<bool>("rs");
    int camId = parser.get<int>("ci");
    String video;

    if(parser.has("v")) {
        video = parser.get<String>("v");
    }

    if(!parser.check()) {
        parser.printErrors();
        return 0;
    }

    VideoCapture inputVideo;
    int waitTime;
    if(!video.empty()) {
        inputVideo.open(video);
        waitTime = 0;
    } else {
        inputVideo.open(camId);
        waitTime = 10;
    }

    Ptr<aruco::Dictionary> dictionary;
    if (parser.has("d")) {
        int dictionaryId = parser.get<int>("d");
        dictionary = aruco::getPredefinedDictionary(aruco::PREDEFINED_DICTIONARY_NAME(dictionaryId));
    }
    else if (parser.has("cd")) {
        FileStorage fs(parser.get<std::string>("cd"), FileStorage::READ);
        bool readOk = aruco::Dictionary::readDictionary(fs.root(), dictionary);
        if(!readOk) {
            cerr << "Invalid dictionary file" << endl;
            return 0;
        }
    }
    else {
        cerr << "Dictionary not specified" << endl;
        return 0;
    }

    // create charuco board object
    Ptr<aruco::CharucoBoard> charucoboard =
            aruco::CharucoBoard::create(squaresX, squaresY, squareLength, markerLength, dictionary);
    Ptr<aruco::Board> board = charucoboard.staticCast<aruco::Board>();

    // collect data from each frame
    vector< vector< vector< Point2f > > > allCorners;
    vector< vector< int > > allIds;
    vector< Mat > allImgs;
    Size imgSize;

    while(inputVideo.grab()) {
        Mat image, imageCopy;
        inputVideo.retrieve(image);

        vector< int > ids;
        vector< vector< Point2f > > corners, rejected;

        // detect markers
        aruco::detectMarkers(image, dictionary, corners, ids, detectorParams, rejected);

        // refind strategy to detect more markers
        if(refindStrategy) aruco::refineDetectedMarkers(image, board, corners, ids, rejected);

        // interpolate charuco corners
        Mat currentCharucoCorners, currentCharucoIds;
        if(ids.size() > 0)
            aruco::interpolateCornersCharuco(corners, ids, image, charucoboard, currentCharucoCorners,
                                             currentCharucoIds);

        // draw results
        image.copyTo(imageCopy);
        if(ids.size() > 0) aruco::drawDetectedMarkers(imageCopy, corners);

        if(currentCharucoCorners.total() > 0)
            aruco::drawDetectedCornersCharuco(imageCopy, currentCharucoCorners, currentCharucoIds);

        putText(imageCopy, "Press 'c' to add current frame. 'ESC' to finish and calibrate",
                Point(10, 20), FONT_HERSHEY_SIMPLEX, 0.5, Scalar(255, 0, 0), 2);

        imshow("out", imageCopy);
        char key = (char)waitKey(waitTime);
        if(key == 27) break;
        if(key == 'c' && ids.size() > 0) {
            cout << "Frame captured" << endl;
            allCorners.push_back(corners);
            allIds.push_back(ids);
            allImgs.push_back(image);
            imgSize = image.size();
        }
    }

    if(allIds.size() < 1) {
        cerr << "Not enough captures for calibration" << endl;
        return 0;
    }

    Mat cameraMatrix, distCoeffs;
    vector< Mat > rvecs, tvecs;
    double repError;

    if(calibrationFlags & CALIB_FIX_ASPECT_RATIO) {
        cameraMatrix = Mat::eye(3, 3, CV_64F);
        cameraMatrix.at< double >(0, 0) = aspectRatio;
    }

    // prepare data for calibration
    vector< vector< Point2f > > allCornersConcatenated;
    vector< int > allIdsConcatenated;
    vector< int > markerCounterPerFrame;
    markerCounterPerFrame.reserve(allCorners.size());
    for(unsigned int i = 0; i < allCorners.size(); i++) {
        markerCounterPerFrame.push_back((int)allCorners[i].size());
        for(unsigned int j = 0; j < allCorners[i].size(); j++) {
            allCornersConcatenated.push_back(allCorners[i][j]);
            allIdsConcatenated.push_back(allIds[i][j]);
        }
    }

    // calibrate camera using aruco markers
    double arucoRepErr;
    arucoRepErr = aruco::calibrateCameraAruco(allCornersConcatenated, allIdsConcatenated,
                                              markerCounterPerFrame, board, imgSize, cameraMatrix,
                                              distCoeffs, noArray(), noArray(), calibrationFlags);

    // prepare data for charuco calibration
    int nFrames = (int)allCorners.size();
    vector< Mat > allCharucoCorners;
    vector< Mat > allCharucoIds;
    vector< Mat > filteredImages;
    allCharucoCorners.reserve(nFrames);
    allCharucoIds.reserve(nFrames);

    for(int i = 0; i < nFrames; i++) {
        // interpolate using camera parameters
        Mat currentCharucoCorners, currentCharucoIds;
        aruco::interpolateCornersCharuco(allCorners[i], allIds[i], allImgs[i], charucoboard,
                                         currentCharucoCorners, currentCharucoIds, cameraMatrix,
                                         distCoeffs);

        allCharucoCorners.push_back(currentCharucoCorners);
        allCharucoIds.push_back(currentCharucoIds);
        filteredImages.push_back(allImgs[i]);
    }

    if(allCharucoCorners.size() < 4) {
        cerr << "Not enough corners for calibration" << endl;
        return 0;
    }

    // calibrate camera using charuco
    repError =
        aruco::calibrateCameraCharuco(allCharucoCorners, allCharucoIds, charucoboard, imgSize,
                                      cameraMatrix, distCoeffs, rvecs, tvecs, calibrationFlags);

    bool saveOk =  saveCameraParams(outputFile, imgSize, aspectRatio, calibrationFlags,
                                    cameraMatrix, distCoeffs, repError);
    if(!saveOk) {
        cerr << "Cannot save output file" << endl;
        return 0;
    }

    cout << "Rep Error: " << repError << endl;
    cout << "Rep Error Aruco: " << arucoRepErr << endl;
    cout << "Calibration saved to " << outputFile << endl;

    // show interpolated charuco corners for debugging
    if(showChessboardCorners) {
        for(unsigned int frame = 0; frame < filteredImages.size(); frame++) {
            Mat imageCopy = filteredImages[frame].clone();
            if(allIds[frame].size() > 0) {

                if(allCharucoCorners[frame].total() > 0) {
                    aruco::drawDetectedCornersCharuco( imageCopy, allCharucoCorners[frame],
                                                       allCharucoIds[frame]);
                }
            }

            imshow("out", imageCopy);
            char key = (char)waitKey(0);
            if(key == 27) break;
        }
    }

    return 0;
}