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  • 相机标定 matlab opencv ROS三种方法标定步骤(2)

    二  ubuntu下Opencv的相机标定

            一般直接用Opencv的源码就可以进行相机的标定,但是可能只是会实现结果,却不懂实现的过程,我也是模模糊糊的看了《计算机视觉中的多视图几何》以及实现一些经典的算法,对Opencv有一些了解才开始做相机的标定,可以先看看源码:

    #include <iostream>
    #include <sstream>
    #include <time.h>
    #include <stdio.h>
    
    #include <opencv2/core/core.hpp>
    #include <opencv2/imgproc/imgproc.hpp>
    #include <opencv2/calib3d/calib3d.hpp>
    #include <opencv2/highgui/highgui.hpp>
    
    #ifndef _CRT_SECURE_NO_WARNINGS
    # define _CRT_SECURE_NO_WARNINGS
    #endif
    
    using namespace cv;
    using namespace std;
    
    static void help()
    {
        cout <<  "This is a camera calibration sample." << endl
             <<  "Usage: calibration configurationFile"  << endl
             <<  "Near the sample file you'll find the configuration file, which has detailed help of "
                 "how to edit it.  It may be any OpenCV supported file format XML/YAML." << endl;
    }
    class Settings
    {
    public:
        Settings() : goodInput(false) {}
        enum Pattern { NOT_EXISTING, CHESSBOARD, CIRCLES_GRID, ASYMMETRIC_CIRCLES_GRID };
        enum InputType {INVALID, CAMERA, VIDEO_FILE, IMAGE_LIST};
    
        void write(FileStorage& fs) const                        //Write serialization for this class
        {
            fs << "{" << "BoardSize_Width"  << boardSize.width
                      << "BoardSize_Height" << boardSize.height
                      << "Square_Size"         << squareSize
                      << "Calibrate_Pattern" << patternToUse
                      << "Calibrate_NrOfFrameToUse" << nrFrames
                      << "Calibrate_FixAspectRatio" << aspectRatio
                      << "Calibrate_AssumeZeroTangentialDistortion" << calibZeroTangentDist
                      << "Calibrate_FixPrincipalPointAtTheCenter" << calibFixPrincipalPoint
    
                      << "Write_DetectedFeaturePoints" << bwritePoints
                      << "Write_extrinsicParameters"   << bwriteExtrinsics
                      << "Write_outputFileName"  << outputFileName
    
                      << "Show_UndistortedImage" << showUndistorsed
    
                      << "Input_FlipAroundHorizontalAxis" << flipVertical
                      << "Input_Delay" << delay
                      << "Input" << input
               << "}";
        }
        void read(const FileNode& node)                          //Read serialization for this class
        {
            node["BoardSize_Width" ] >> boardSize.width;
            node["BoardSize_Height"] >> boardSize.height;
            node["Calibrate_Pattern"] >> patternToUse;
            node["Square_Size"]  >> squareSize;
            node["Calibrate_NrOfFrameToUse"] >> nrFrames;
            node["Calibrate_FixAspectRatio"] >> aspectRatio;
            node["Write_DetectedFeaturePoints"] >> bwritePoints;
            node["Write_extrinsicParameters"] >> bwriteExtrinsics;
            node["Write_outputFileName"] >> outputFileName;
            node["Calibrate_AssumeZeroTangentialDistortion"] >> calibZeroTangentDist;
            node["Calibrate_FixPrincipalPointAtTheCenter"] >> calibFixPrincipalPoint;
            node["Input_FlipAroundHorizontalAxis"] >> flipVertical;
            node["Show_UndistortedImage"] >> showUndistorsed;
            node["Input"] >> input;
            node["Input_Delay"] >> delay;
            interprate();
        }
        void interprate()
        {
            goodInput = true;
            if (boardSize.width <= 0 || boardSize.height <= 0)
            {
                cerr << "Invalid Board size: " << boardSize.width << " " << boardSize.height << endl;
                goodInput = false;
            }
            if (squareSize <= 10e-6)
            {
                cerr << "Invalid square size " << squareSize << endl;
                goodInput = false;
            }
            if (nrFrames <= 0)
            {
                cerr << "Invalid number of frames " << nrFrames << endl;
                goodInput = false;
            }
    
            if (input.empty())      // Check for valid input
                    inputType = INVALID;
            else
            {
                if (input[0] >= '0' && input[0] <= '9')
                {
                    stringstream ss(input);
                    ss >> cameraID;
                    inputType = CAMERA;
                }
                else
                {
                    if (readStringList(input, imageList))
                        {
                            inputType = IMAGE_LIST;
                            nrFrames = (nrFrames < (int)imageList.size()) ? nrFrames : (int)imageList.size();
                        }
                    else
                        inputType = VIDEO_FILE;
                }
                if (inputType == CAMERA)
                    inputCapture.open(cameraID);
                if (inputType == VIDEO_FILE)
                    inputCapture.open(input);
                if (inputType != IMAGE_LIST && !inputCapture.isOpened())
                        inputType = INVALID;
            }
            if (inputType == INVALID)
            {
                cerr << " Inexistent input: " << input;
                goodInput = false;
            }
    
            flag = 0;
            if(calibFixPrincipalPoint) flag |= CV_CALIB_FIX_PRINCIPAL_POINT;
            if(calibZeroTangentDist)   flag |= CV_CALIB_ZERO_TANGENT_DIST;
            if(aspectRatio)            flag |= CV_CALIB_FIX_ASPECT_RATIO;
    
    
            calibrationPattern = NOT_EXISTING;
            if (!patternToUse.compare("CHESSBOARD")) calibrationPattern = CHESSBOARD;
            if (!patternToUse.compare("CIRCLES_GRID")) calibrationPattern = CIRCLES_GRID;
            if (!patternToUse.compare("ASYMMETRIC_CIRCLES_GRID")) calibrationPattern = ASYMMETRIC_CIRCLES_GRID;
            if (calibrationPattern == NOT_EXISTING)
                {
                    cerr << " Inexistent camera calibration mode: " << patternToUse << endl;
                    goodInput = false;
                }
            atImageList = 0;
    
        }
        Mat nextImage()
        {
            Mat result;
            if( inputCapture.isOpened() )
            {
                Mat view0;
                inputCapture >> view0;
                view0.copyTo(result);
            }
            else if( atImageList < (int)imageList.size() )
                result = imread(imageList[atImageList++], CV_LOAD_IMAGE_COLOR);
    
            return result;
        }
    
        static bool readStringList( const string& filename, vector<string>& l )
        {
            l.clear();
            FileStorage fs(filename, FileStorage::READ);
            if( !fs.isOpened() )
                return false;
            FileNode n = fs.getFirstTopLevelNode();
            if( n.type() != FileNode::SEQ )
                return false;
            FileNodeIterator it = n.begin(), it_end = n.end();
            for( ; it != it_end; ++it )
                l.push_back((string)*it);
            return true;
        }
    public:
        Size boardSize;            // The size of the board -> Number of items by width and height
        Pattern calibrationPattern;// One of the Chessboard, circles, or asymmetric circle pattern
        float squareSize;          // The size of a square in your defined unit (point, millimeter,etc).
        int nrFrames;              // The number of frames to use from the input for calibration
        float aspectRatio;         // The aspect ratio
        int delay;                 // In case of a video input
        bool bwritePoints;         //  Write detected feature points
        bool bwriteExtrinsics;     // Write extrinsic parameters
        bool calibZeroTangentDist; // Assume zero tangential distortion
        bool calibFixPrincipalPoint;// Fix the principal point at the center
        bool flipVertical;          // Flip the captured images around the horizontal axis
        string outputFileName;      // The name of the file where to write
        bool showUndistorsed;       // Show undistorted images after calibration
        string input;               // The input ->
    
    
    
        int cameraID;
        vector<string> imageList;
        int atImageList;
        VideoCapture inputCapture;
        InputType inputType;
        bool goodInput;
        int flag;
    
    private:
        string patternToUse;
    
    
    };
    
    static void read(const FileNode& node, Settings& x, const Settings& default_value = Settings())
    {
        if(node.empty())
            x = default_value;
        else
            x.read(node);
    }
    
    enum { DETECTION = 0, CAPTURING = 1, CALIBRATED = 2 };
    
    bool runCalibrationAndSave(Settings& s, Size imageSize, Mat&  cameraMatrix, Mat& distCoeffs,
                               vector<vector<Point2f> > imagePoints );
    
    int main(int argc, char* argv[])
    {
        help();
        Settings s;
        const string inputSettingsFile = argc > 1 ? argv[1] : "default.xml";
        FileStorage fs(inputSettingsFile, FileStorage::READ); // Read the settings
        if (!fs.isOpened())
        {
            cout << "Could not open the configuration file: "" << inputSettingsFile << """ << endl;
            return -1;
        }
        fs["Settings"] >> s;
        fs.release();                                         // close Settings file
    
        if (!s.goodInput)
        {
            cout << "Invalid input detected. Application stopping. " << endl;
            return -1;
        }
    
        vector<vector<Point2f> > imagePoints;
        Mat cameraMatrix, distCoeffs;
        Size imageSize;
        int mode = s.inputType == Settings::IMAGE_LIST ? CAPTURING : DETECTION;
        clock_t prevTimestamp = 0;
        const Scalar RED(0,0,255), GREEN(0,255,0);
        const char ESC_KEY = 27;
    
        for(int i = 0;;++i)
        {
          Mat view;
          bool blinkOutput = false;
    
          view = s.nextImage();
    
          //-----  If no more image, or got enough, then stop calibration and show result -------------
          if( mode == CAPTURING && imagePoints.size() >= (unsigned)s.nrFrames )
          {
              if( runCalibrationAndSave(s, imageSize,  cameraMatrix, distCoeffs, imagePoints))
                  mode = CALIBRATED;
              else
                  mode = DETECTION;
          }
          if(view.empty())          // If no more images then run calibration, save and stop loop.
          {
                if( imagePoints.size() > 0 )
                    runCalibrationAndSave(s, imageSize,  cameraMatrix, distCoeffs, imagePoints);
                break;
          }
    
    
            imageSize = view.size();  // Format input image.
            if( s.flipVertical )    flip( view, view, 0 );
    
            vector<Point2f> pointBuf;
    
            bool found;
            switch( s.calibrationPattern ) // Find feature points on the input format
            {
            case Settings::CHESSBOARD:
                found = findChessboardCorners( view, s.boardSize, pointBuf,
                    CV_CALIB_CB_ADAPTIVE_THRESH | CV_CALIB_CB_FAST_CHECK | CV_CALIB_CB_NORMALIZE_IMAGE);
                break;
            case Settings::CIRCLES_GRID:
                found = findCirclesGrid( view, s.boardSize, pointBuf );
                break;
            case Settings::ASYMMETRIC_CIRCLES_GRID:
                found = findCirclesGrid( view, s.boardSize, pointBuf, CALIB_CB_ASYMMETRIC_GRID );
                break;
            default:
                found = false;
                break;
            }
    
            if ( found)                // If done with success,
            {
                  // improve the found corners' coordinate accuracy for chessboard
                    if( s.calibrationPattern == Settings::CHESSBOARD)
                    {
                        Mat viewGray;
                        cvtColor(view, viewGray, COLOR_BGR2GRAY);
                        cornerSubPix( viewGray, pointBuf, Size(11,11),
                            Size(-1,-1), TermCriteria( CV_TERMCRIT_EPS+CV_TERMCRIT_ITER, 30, 0.1 ));
                    }
    
                    if( mode == CAPTURING &&  // For camera only take new samples after delay time
                        (!s.inputCapture.isOpened() || clock() - prevTimestamp > s.delay*1e-3*CLOCKS_PER_SEC) )
                    {
                        imagePoints.push_back(pointBuf);
                        prevTimestamp = clock();
                        blinkOutput = s.inputCapture.isOpened();
                    }
    
                    // Draw the corners.
                    drawChessboardCorners( view, s.boardSize, Mat(pointBuf), found );
            }
    
            //----------------------------- Output Text ------------------------------------------------
            string msg = (mode == CAPTURING) ? "100/100" :
                          mode == CALIBRATED ? "Calibrated" : "Press 'g' to start";
            int baseLine = 0;
            Size textSize = getTextSize(msg, 1, 1, 1, &baseLine);
            Point textOrigin(view.cols - 2*textSize.width - 10, view.rows - 2*baseLine - 10);
    
            if( mode == CAPTURING )
            {
                if(s.showUndistorsed)
                    msg = format( "%d/%d Undist", (int)imagePoints.size(), s.nrFrames );
                else
                    msg = format( "%d/%d", (int)imagePoints.size(), s.nrFrames );
            }
    
            putText( view, msg, textOrigin, 1, 1, mode == CALIBRATED ?  GREEN : RED);
    
            if( blinkOutput )
                bitwise_not(view, view);
    
            //------------------------- Video capture  output  undistorted ------------------------------
            if( mode == CALIBRATED && s.showUndistorsed )
            {
                Mat temp = view.clone();
                undistort(temp, view, cameraMatrix, distCoeffs);
            }
    
            //------------------------------ Show image and check for input commands -------------------
            imshow("Image View", view);
            char key = (char)waitKey(s.inputCapture.isOpened() ? 50 : s.delay);
    
            if( key  == ESC_KEY )
                break;
    
            if( key == 'u' && mode == CALIBRATED )
               s.showUndistorsed = !s.showUndistorsed;
    
            if( s.inputCapture.isOpened() && key == 'g' )
            {
                mode = CAPTURING;
                imagePoints.clear();
            }
        }
    
        // -----------------------Show the undistorted image for the image list ------------------------
        if( s.inputType == Settings::IMAGE_LIST && s.showUndistorsed )
        {
            Mat view, rview, map1, map2;
            initUndistortRectifyMap(cameraMatrix, distCoeffs, Mat(),
                getOptimalNewCameraMatrix(cameraMatrix, distCoeffs, imageSize, 1, imageSize, 0),
                imageSize, CV_16SC2, map1, map2);
    
            for(int i = 0; i < (int)s.imageList.size(); i++ )
            {
                view = imread(s.imageList[i], 1);
                if(view.empty())
                    continue;
                remap(view, rview, map1, map2, INTER_LINEAR);
                imshow("Image View", rview);
                char c = (char)waitKey();
                if( c  == ESC_KEY || c == 'q' || c == 'Q' )
                    break;
            }
        }
    
    
        return 0;
    }
    
    static double computeReprojectionErrors( const vector<vector<Point3f> >& objectPoints,
                                             const vector<vector<Point2f> >& imagePoints,
                                             const vector<Mat>& rvecs, const vector<Mat>& tvecs,
                                             const Mat& cameraMatrix , const Mat& distCoeffs,
                                             vector<float>& perViewErrors)
    {
        vector<Point2f> imagePoints2;
        int i, totalPoints = 0;
        double totalErr = 0, err;
        perViewErrors.resize(objectPoints.size());
    
        for( i = 0; i < (int)objectPoints.size(); ++i )
        {
            projectPoints( Mat(objectPoints[i]), rvecs[i], tvecs[i], cameraMatrix,
                           distCoeffs, imagePoints2);
            err = norm(Mat(imagePoints[i]), Mat(imagePoints2), CV_L2);
    
            int n = (int)objectPoints[i].size();
            perViewErrors[i] = (float) std::sqrt(err*err/n);
            totalErr        += err*err;
            totalPoints     += n;
        }
    
        return std::sqrt(totalErr/totalPoints);
    }
    
    static void calcBoardCornerPositions(Size boardSize, float squareSize, vector<Point3f>& corners,
                                         Settings::Pattern patternType /*= Settings::CHESSBOARD*/)
    {
        corners.clear();
    
        switch(patternType)
        {
        case Settings::CHESSBOARD:
        case Settings::CIRCLES_GRID:
            for( int i = 0; i < boardSize.height; ++i )
                for( int j = 0; j < boardSize.width; ++j )
                    corners.push_back(Point3f(float( j*squareSize ), float( i*squareSize ), 0));
            break;
    
        case Settings::ASYMMETRIC_CIRCLES_GRID:
            for( int i = 0; i < boardSize.height; i++ )
                for( int j = 0; j < boardSize.width; j++ )
                    corners.push_back(Point3f(float((2*j + i % 2)*squareSize), float(i*squareSize), 0));
            break;
        default:
            break;
        }
    }
    
    static bool runCalibration( Settings& s, Size& imageSize, Mat& cameraMatrix, Mat& distCoeffs,
                                vector<vector<Point2f> > imagePoints, vector<Mat>& rvecs, vector<Mat>& tvecs,
                                vector<float>& reprojErrs,  double& totalAvgErr)
    {
    
        cameraMatrix = Mat::eye(3, 3, CV_64F);
        if( s.flag & CV_CALIB_FIX_ASPECT_RATIO )
            cameraMatrix.at<double>(0,0) = 1.0;
    
        distCoeffs = Mat::zeros(8, 1, CV_64F);
    
        vector<vector<Point3f> > objectPoints(1);
        calcBoardCornerPositions(s.boardSize, s.squareSize, objectPoints[0], s.calibrationPattern);
    
        objectPoints.resize(imagePoints.size(),objectPoints[0]);
    
        //Find intrinsic and extrinsic camera parameters
        double rms = calibrateCamera(objectPoints, imagePoints, imageSize, cameraMatrix,
                                     distCoeffs, rvecs, tvecs, s.flag|CV_CALIB_FIX_K4|CV_CALIB_FIX_K5);
    
        cout << "Re-projection error reported by calibrateCamera: "<< rms << endl;
    
        bool ok = checkRange(cameraMatrix) && checkRange(distCoeffs);
    
        totalAvgErr = computeReprojectionErrors(objectPoints, imagePoints,
                                                 rvecs, tvecs, cameraMatrix, distCoeffs, reprojErrs);
    
        return ok;
    }
    
    // Print camera parameters to the output file
    static void saveCameraParams( Settings& s, Size& imageSize, Mat& cameraMatrix, Mat& distCoeffs,
                                  const vector<Mat>& rvecs, const vector<Mat>& tvecs,
                                  const vector<float>& reprojErrs, const vector<vector<Point2f> >& imagePoints,
                                  double totalAvgErr )
    {
        FileStorage fs( s.outputFileName, FileStorage::WRITE );
    
        time_t tm;
        time( &tm );
        struct tm *t2 = localtime( &tm );
        char buf[1024];
        strftime( buf, sizeof(buf)-1, "%c", t2 );
    
        fs << "calibration_Time" << buf;
    
        if( !rvecs.empty() || !reprojErrs.empty() )
            fs << "nrOfFrames" << (int)std::max(rvecs.size(), reprojErrs.size());
        fs << "image_Width" << imageSize.width;
        fs << "image_Height" << imageSize.height;
        fs << "board_Width" << s.boardSize.width;
        fs << "board_Height" << s.boardSize.height;
        fs << "square_Size" << s.squareSize;
    
        if( s.flag & CV_CALIB_FIX_ASPECT_RATIO )
            fs << "FixAspectRatio" << s.aspectRatio;
    
        if( s.flag )
        {
            sprintf( buf, "flags: %s%s%s%s",
                s.flag & CV_CALIB_USE_INTRINSIC_GUESS ? " +use_intrinsic_guess" : "",
                s.flag & CV_CALIB_FIX_ASPECT_RATIO ? " +fix_aspectRatio" : "",
                s.flag & CV_CALIB_FIX_PRINCIPAL_POINT ? " +fix_principal_point" : "",
                s.flag & CV_CALIB_ZERO_TANGENT_DIST ? " +zero_tangent_dist" : "" );
            cvWriteComment( *fs, buf, 0 );
    
        }
    
        fs << "flagValue" << s.flag;
    
        fs << "Camera_Matrix" << cameraMatrix;
        fs << "Distortion_Coefficients" << distCoeffs;
    
        fs << "Avg_Reprojection_Error" << totalAvgErr;
        if( !reprojErrs.empty() )
            fs << "Per_View_Reprojection_Errors" << Mat(reprojErrs);
    
        if( !rvecs.empty() && !tvecs.empty() )
        {
            CV_Assert(rvecs[0].type() == tvecs[0].type());
            Mat bigmat((int)rvecs.size(), 6, rvecs[0].type());
            for( int i = 0; i < (int)rvecs.size(); i++ )
            {
                Mat r = bigmat(Range(i, i+1), Range(0,3));
                Mat t = bigmat(Range(i, i+1), Range(3,6));
    
                CV_Assert(rvecs[i].rows == 3 && rvecs[i].cols == 1);
                CV_Assert(tvecs[i].rows == 3 && tvecs[i].cols == 1);
                //*.t() is MatExpr (not Mat) so we can use assignment operator
                r = rvecs[i].t();
                t = tvecs[i].t();
            }
            cvWriteComment( *fs, "a set of 6-tuples (rotation vector + translation vector) for each view", 0 );
            fs << "Extrinsic_Parameters" << bigmat;
        }
    
        if( !imagePoints.empty() )
        {
            Mat imagePtMat((int)imagePoints.size(), (int)imagePoints[0].size(), CV_32FC2);
            for( int i = 0; i < (int)imagePoints.size(); i++ )
            {
                Mat r = imagePtMat.row(i).reshape(2, imagePtMat.cols);
                Mat imgpti(imagePoints[i]);
                imgpti.copyTo(r);
            }
            fs << "Image_points" << imagePtMat;
        }
    }
    
    bool runCalibrationAndSave(Settings& s, Size imageSize, Mat&  cameraMatrix, Mat& distCoeffs,vector<vector<Point2f> > imagePoints )
    {
        vector<Mat> rvecs, tvecs;
        vector<float> reprojErrs;
        double totalAvgErr = 0;
    
        bool ok = runCalibration(s,imageSize, cameraMatrix, distCoeffs, imagePoints, rvecs, tvecs,
                                 reprojErrs, totalAvgErr);
        cout << (ok ? "Calibration succeeded" : "Calibration failed")
            << ". avg re projection error = "  << totalAvgErr ;
    
        if( ok )
            saveCameraParams( s, imageSize, cameraMatrix, distCoeffs, rvecs ,tvecs, reprojErrs,
                                imagePoints, totalAvgErr);
        return ok;
    }
    View Code

    网上有很多关于相机标定的代码,但都是没有官方网站的源文件更详细,给源文件同时写一个Makefile文件

    #Makefile for camera_calibrateion
    EXE =camera_calibration
    OBJS += camera_calibration.o
    
    
    CC = g++
    CFLAGS += -g -O3 -Wall
    INC += -I. `pkg-config --cflags opencv`
    LIBS += `pkg-config --libs opencv`
    
    all:$(EXE)
    
    $(EXE):$(OBJS)
    	$(CC) $(INC) $(CFLAGS) $(OBJS) -o $(EXE) $(LIBS)
    $(OBJS):%.o:%.cpp
    	$(CC) $(INC) $(CFLAGS) -c $< -o $@
    
    .PHONY:clean
    clean:
    	rm -r *.o $(EXE)
    

     然后make一下就会生成可执行文件,那么同时还要有一个配置文件 .xml  要在同一个目录文件下,原文件提供了三种方式进行标定,

               (1)  直接输入摄像头信息   

               (2)采用已经采集好的多照不同位置的标定模板 

               (3 )使用采集下的视频流文件

    那么我这里只做了(1)  (2)并且标定不同的摄像头

    (1)采用摄像头的输入方式的mycamera.xml 代码如下:(同时要在camera_calibration.cpp文件里更改读取的.xml文件)

    (这里的标定模板我是用A3纸张打印出来,为8*6     35mm的标定棋盘)

    <?xml version="1.0"?>
    <opencv_storage>
               <!--设置标定参数-->
    <Settings>
    
               <!-- Number of inner corners per a item row and column. 宽度和高度的设置(square, circle) -->
    <BoardSize_Width> 8</BoardSize_Width>  
    <BoardSize_Height>6</BoardSize_Height>
    
               <!-- The size of a square in some user defined metric system 每个方格的边长的长度单位一般是mm(pixel, millimeter)-->
    <Square_Size>35</Square_Size>
    
             <!-- The type of input used for camera calibration. 标定模板的样式(棋盘)
             这里一共有三种模板One of: CHESSBOARD CIRCLES_GRID ASYMMETRIC_CIRCLES_GRID -->
    <Calibrate_Pattern>"CHESSBOARD"</Calibrate_Pattern>
    
                    <!-- The input to use for calibration. 
    		To use an input camera -> give the ID of the camera, like "1"
    		To use an input video  -> give the path of the input video, like "/tmp/x.avi"
    		To use an image list   -> give the path to the XML or YAML file containing the list of the images, 
                    like "/tmp/circles_list.xml"
    		输入标定模板的方式有三种方式:摄像头输入;视频输入;照片文件流输入-->
    <Input>"1"</Input>
    
    
    
                  <!--  If true (non-zero) we flip the input images around the horizontal axis.
                     如果为真(非零),安照垂直方向翻转输入图像,这里选择为零,即不翻转-->
    <Input_FlipAroundHorizontalAxis>0</Input_FlipAroundHorizontalAxis>
     
                      <!-- Time delay between frames in case of camera.在使用相机的情况下的帧之间的时间延迟 -->
    <Input_Delay>100</Input_Delay>
                      <!-- How many frames to use, for calibration.用多少帧照片去校准,可以自己设置,一般不能低于20个 -->
    <Calibrate_NrOfFrameToUse>25</Calibrate_NrOfFrameToUse>
                     <!-- Consider only fy as a free parameter, the ratio fx/fy stays the same as in the input cameraMatrix. 
    	           Use or not setting. 0 - False Non-Zero - True
                        假设fy是一个自由参数,而fx/fy是一个固定的比例参数,使用或者不设置 0    假  非零  真-->
    <Calibrate_FixAspectRatio> 1 </Calibrate_FixAspectRatio>
                    <!-- If true (non-zero) tangential distortion coefficients  are set to zeros and stay zero.
                     如果设置为真,表示切向畸变系数被设置为0  保持为零-->
    <Calibrate_AssumeZeroTangentialDistortion>1</Calibrate_AssumeZeroTangentialDistortion>
                     <!-- If true (non-zero) the principal point(摄像机坐标系下真实的坐标原点) is not changed during the global optimization.-->
    <Calibrate_FixPrincipalPointAtTheCenter> 1 </Calibrate_FixPrincipalPointAtTheCenter>
                       <!-- The name of the output log file. 输出文件的名称-->
    <Write_outputFileName>"out_camera_data.xml"</Write_outputFileName>
                      <!-- If true (non-zero) we write to the output file the feature points.(如果为真我们向输出文件写入特征点)-->
    <Write_DetectedFeaturePoints>1</Write_DetectedFeaturePoints>
                      <!-- If true (non-zero) we write to the output file the extrinsic camera parameters.(写入相机的外部参数)-->
    <Write_extrinsicParameters>1</Write_extrinsicParameters>
                             <!-- If true (non-zero) we show after calibration the undistorted images.展示校准后不失真的照片-->
     <Show_UndistortedImage>1</Show_UndistortedImage>
    
    </Settings>
    
    </opencv_storage>
    

     里面的汉字是我写的标注,其中有几个地方需要修改的与我们的实际标定模板一致

    <BoardSize_Width> 8</BoardSize_Width>      :表示标定模板的宽度  实际一共有9个黑白方格
    <BoardSize_Height>6</BoardSize_Height>      :实际有7个黑白方格
    <Calibrate_Pattern>"CHESSBOARD"</Calibrate_Pattern>    :选择棋盘形式,一共有  CHESSBOARD ,CIRCLES_GRID, ASYMMETRIC_CIRCLES_GRID三种

    <Square_Size>35</Square_Size>             :每个黑白方格的边长35mm(根据实际情况)

    <Input>"1"</Input>                   :选择标定模板的输入种类  1. To use an input camera -> give the ID of the camera, like "1"
                                                               2. To use an input video  -> give the path of the input video, like "/tmp/x.avi"
                                                               3. To use an image list   -> give the path to the XML or YAML file containing the list of the images,      <Write_outputFileName>"out_camera_data.xml"</Write_outputFileName>  
    <Write_outputFileName>"out_camera_data.xml"</Write_outputFileName>   :表示标定输出文件

    运行文件夹下运行./camera_calibration  会启动摄像头,然后选择“g”开始标定   ,但是如果上面的这些参数没有设置的与实际相符合,是不会开始采集标定模板的,(我刚开始就出现了这个错误,所以一定亚设置与实际的标定模板一致)

    就会开始采集25个不同角度和位置的标定模板,如下图:

    注意(我这样直接拿着标定模板来标定是不正确的,应该用一个平面模板把标定模板固定住,这样的标定的结果才是更加准确的,因为这样只是做实验,)

    每采集成功一次就会变为二图,颜色略有变化,采集完成就会自动开始校准如下:

    此时在工程文件夹下就会生成out_camera_data.xml,就是相机的标定结果报告

    (2)使用Opencv 提供的标定模板进行标定

      我们只需要更改

    <BoardSize_Width> 8</BoardSize_Width>   改为   <BoardSize_Width> 6</BoardSize_Width>        
    <BoardSize_Height>6</BoardSize_Height>   改为  <BoardSize_Height>4</BoardSize_Height>
    <Square_Size>35</Square_Size>      改为     <Square_Size108</Square_Size>
    <Input>"1"</Input>      改为     <Input>"/home/salm/myopencv/calibrate/VID.xml"</Input>       
    这里就是指定了另一个.xml文件,就是标定模板的图片,其中VID.xml内容为:
    <?xml version="1.0"?>
    <opencv_storage>
    <images>
    /home/salm/myopencv/images/chessboards/chessboard01.jpg
    /home/salm/myopencv/images/chessboards/chessboard02.jpg
    /home/salm/myopencv/images/chessboards/chessboard03.jpg
    /home/salm/myopencv/images/chessboards/chessboard04.jpg
    /home/salm/myopencv/images/chessboards/chessboard05.jpg
    /home/salm/myopencv/images/chessboards/chessboard06.jpg
    /home/salm/myopencv/images/chessboards/chessboard07.jpg
    /home/salm/myopencv/images/chessboards/chessboard08.jpg
    /home/salm/myopencv/images/chessboards/chessboard09.jpg
    /home/salm/myopencv/images/chessboards/chessboard10.jpg
    /home/salm/myopencv/images/chessboards/chessboard11.jpg
    /home/salm/myopencv/images/chessboards/chessboard12.jpg
    /home/salm/myopencv/images/chessboards/chessboard13.jpg
    /home/salm/myopencv/images/chessboards/chessboard14.jpg
    /home/salm/myopencv/images/chessboards/chessboard15.jpg
    /home/salm/myopencv/images/chessboards/chessboard16.jpg
    /home/salm/myopencv/images/chessboards/chessboard17.jpg
    /home/salm/myopencv/images/chessboards/chessboard18.jpg
    /home/salm/myopencv/images/chessboards/chessboard19.jpg
    /home/salm/myopencv/images/chessboards/chessboard20.jpg
    /home/salm/myopencv/images/chessboards/chessboard21.jpg
    /home/salm/myopencv/images/chessboards/chessboard22.jpg
    /home/salm/myopencv/images/chessboards/chessboard23.jpg
    /home/salm/myopencv/images/chessboards/chessboard24.jpg
    /home/salm/myopencv/images/chessboards/chessboard25.jpg
    </images>
    </opencv_storage>
    

     运行文件夹下运行./camera_calibration  会启动VID.xml文件下的图片,这是标定过程中的截图文件 如图

     

    此时在工程文件夹下就会生成out_camera_data.xml

    后续还有其他相关的只是待我学习完了再写出来,只是为了记录我的实验过程,如果能有人从中获取帮助,那就更好了

    (如果很不幸,被大神们看见了,就直接嗤之以鼻吧,因为没有什么创新的东西,谢谢)

    如果您觉得看完有所收获,可以资助一分,几分money,不在乎多少(我也是跟网上的大神们学的),不想挣钱娶媳妇的程序员不是好程序员(同时我也看看到底有没有人认可),谢谢

            

    版权所有,转载请注明出处 http://www.cnblogs.com/li-yao7758258/p/5933653.html
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  • 原文地址:https://www.cnblogs.com/li-yao7758258/p/5933653.html
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