improve doc and added new tutorial cpp file for charuco detection

reformatted the documentation

modules/aruco/samples/tutorial_charuco_create_detect.cpp

+//! [charucohdr]
+#include <opencv2/aruco/charuco.hpp>
+//! [charucohdr]
+#include <opencv2/highgui.hpp>
+#include <iostream>
+#include <string>
+
+namespace {
+const char* about = "A tutorial code on charuco board creation and detection of charuco board with and without camera caliberation";
+const char* keys = "{c        |       | Put value of c=1 to create charuco board;\nc=2 to detect charuco board without camera calibration;\nc=3 to detect charuco board with camera calibration and Pose Estimation}";
+}
+
+void createBoard();
+void detectCharucoBoardWithCalibrationPose();
+void detectCharucoBoardWithoutCalibration();
+
+static bool readCameraParameters(std::string filename, cv::Mat& camMatrix, cv::Mat& distCoeffs)
+{
+    cv::FileStorage fs(filename, cv::FileStorage::READ);
+    if (!fs.isOpened())
+        return false;
+    fs["camera_matrix"] >> camMatrix;
+    fs["distortion_coefficients"] >> distCoeffs;
+    return true;
+}
+
+void createBoard()
+{
+    cv::Ptr<cv::aruco::Dictionary> dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
+    //! [createBoard]
+    cv::Ptr<cv::aruco::CharucoBoard> board = cv::aruco::CharucoBoard::create(5, 7, 0.04f, 0.02f, dictionary);
+    cv::Mat boardImage;
+    board->draw(cv::Size(600, 500), boardImage, 10, 1);
+    //! [createBoard]
+    cv::imwrite("BoardImage.jpg", boardImage);
+}
+
+//! [detwcp]
+void detectCharucoBoardWithCalibrationPose()
+{
+    cv::VideoCapture inputVideo;
+    inputVideo.open(0);
+    //! [matdiscoff]
+    cv::Mat cameraMatrix, distCoeffs;
+    std::string filename = "calib.txt";
+    bool readOk = readCameraParameters(filename, cameraMatrix, distCoeffs);
+    //! [matdiscoff]
+    if (!readOk) {
+        std::cerr << "Invalid camera file" << std::endl;
+    } else {
+        //! [dictboard]
+        cv::Ptr<cv::aruco::Dictionary> dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
+        cv::Ptr<cv::aruco::CharucoBoard> board = cv::aruco::CharucoBoard::create(5, 7, 0.04f, 0.02f, dictionary);
+        cv::Ptr<cv::aruco::DetectorParameters> params = cv::aruco::DetectorParameters::create();
+        //! [dictboard]
+        while (inputVideo.grab()) {
+            //! [inputImg]
+            cv::Mat image;
+            //! [inputImg]
+            cv::Mat imageCopy;
+            inputVideo.retrieve(image);
+            image.copyTo(imageCopy);
+            //! [midcornerdet]
+            std::vector<int> markerIds;
+            std::vector<std::vector<cv::Point2f> > markerCorners;
+            cv::aruco::detectMarkers(image, board->dictionary, markerCorners, markerIds, params);
+            //! [midcornerdet]
+            // if at least one marker detected
+            if (markerIds.size() > 0) {
+                cv::aruco::drawDetectedMarkers(imageCopy, markerCorners, markerIds);
+                //! [charidcor]
+                std::vector<cv::Point2f> charucoCorners;
+                std::vector<int> charucoIds;
+                cv::aruco::interpolateCornersCharuco(markerCorners, markerIds, image, board, charucoCorners, charucoIds, cameraMatrix, distCoeffs);
+                //! [charidcor]
+                // if at least one charuco corner detected
+                if (charucoIds.size() > 0) {
+                    cv::Scalar color = cv::Scalar(255, 0, 0);
+                    //! [detcor]
+                    cv::aruco::drawDetectedCornersCharuco(imageCopy, charucoCorners, charucoIds, color);
+                    //! [detcor]
+                    cv::Vec3d rvec, tvec;
+                    //! [pose]
+                    // cv::aruco::estimatePoseCharucoBoard(charucoCorners, charucoIds, board, cameraMatrix, distCoeffs, rvec, tvec);
+                    //! [pose]
+                    bool valid = cv::aruco::estimatePoseCharucoBoard(charucoCorners, charucoIds, board, cameraMatrix, distCoeffs, rvec, tvec);
+                    // if charuco pose is valid
+                    if (valid)
+                        cv::aruco::drawAxis(imageCopy, cameraMatrix, distCoeffs, rvec, tvec, 0.1f);
+                }
+            }
+            cv::imshow("out", imageCopy);
+            char key = (char)cv::waitKey(30);
+            if (key == 27)
+                break;
+        }
+    }
+}
+//! [detwcp]
+
+//! [detwc]
+void detectCharucoBoardWithoutCalibration()
+{
+    cv::VideoCapture inputVideo;
+    inputVideo.open(0);
+    cv::Ptr<cv::aruco::Dictionary> dictionary = cv::aruco::getPredefinedDictionary(cv::aruco::DICT_6X6_250);
+    cv::Ptr<cv::aruco::CharucoBoard> board = cv::aruco::CharucoBoard::create(5, 7, 0.04f, 0.02f, dictionary);
+
+    cv::Ptr<cv::aruco::DetectorParameters> params = cv::aruco::DetectorParameters::create();
+    params->cornerRefinementMethod = cv::aruco::CORNER_REFINE_NONE;
+    while (inputVideo.grab()) {
+        cv::Mat image, imageCopy;
+        inputVideo.retrieve(image);
+        image.copyTo(imageCopy);
+        std::vector<int> markerIds;
+        std::vector<std::vector<cv::Point2f> > markerCorners;
+        cv::aruco::detectMarkers(image, board->dictionary, markerCorners, markerIds, params);
+        //or
+        //cv::aruco::detectMarkers(image, dictionary, markerCorners, markerIds, params);
+        // if at least one marker detected
+        if (markerIds.size() > 0) {
+            cv::aruco::drawDetectedMarkers(imageCopy, markerCorners, markerIds);
+            //! [charidcorwc]
+            std::vector<cv::Point2f> charucoCorners;
+            std::vector<int> charucoIds;
+            cv::aruco::interpolateCornersCharuco(markerCorners, markerIds, image, board, charucoCorners, charucoIds);
+            //! [charidcorwc]
+            // if at least one charuco corner detected
+            if (charucoIds.size() > 0)
+                cv::aruco::drawDetectedCornersCharuco(imageCopy, charucoCorners, charucoIds, cv::Scalar(255, 0, 0));
+        }
+        cv::imshow("out", imageCopy);
+        char key = (char)cv::waitKey(30);
+        if (key == 27)
+            break;
+    }
+}
+//! [detwc]
+
+int main(int argc, char* argv[])
+{
+    cv::CommandLineParser parser(argc, argv, keys);
+    parser.about(about);
+    if (argc < 2) {
+        parser.printMessage();
+        return 0;
+    }
+    int choose = parser.get<int>("c");
+    switch (choose) {
+    case 1:
+        createBoard();
+        std::cout << "An image named BoardImg.jpg is generated in folder containing this file" << std::endl;
+        break;
+    case 2:
+        detectCharucoBoardWithoutCalibration();
+        break;
+    case 3:
+        detectCharucoBoardWithCalibrationPose();
+        break;
+    default:
+        break;
+    }
+    return 0;
+}
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