This source file includes following definitions.
- help
- computeReprojectionErrors
- calcChessboardCorners
- runCalibration
- saveCameraParams
- readStringList
- runAndSave
- main
#include "opencv2/core.hpp"
#include <opencv2/core/utility.hpp>
#include "opencv2/imgproc.hpp"
#include "opencv2/calib3d.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/videoio.hpp"
#include "opencv2/highgui.hpp"
#include <cctype>
#include <stdio.h>
#include <string.h>
#include <time.h>
using namespace cv;
using namespace std;
const char * usage =
" \nexample command line for calibration from a live feed.\n"
" calibration -w 4 -h 5 -s 0.025 -o camera.yml -op -oe\n"
" \n"
" example command line for calibration from a list of stored images:\n"
" imagelist_creator image_list.xml *.png\n"
" calibration -w 4 -h 5 -s 0.025 -o camera.yml -op -oe image_list.xml\n"
" where image_list.xml is the standard OpenCV XML/YAML\n"
" use imagelist_creator to create the xml or yaml list\n"
" file consisting of the list of strings, e.g.:\n"
" \n"
"<?xml version=\"1.0\"?>\n"
"<opencv_storage>\n"
"<images>\n"
"view000.png\n"
"view001.png\n"
"<!-- view002.png -->\n"
"view003.png\n"
"view010.png\n"
"one_extra_view.jpg\n"
"</images>\n"
"</opencv_storage>\n";
const char* liveCaptureHelp =
"When the live video from camera is used as input, the following hot-keys may be used:\n"
" <ESC>, 'q' - quit the program\n"
" 'g' - start capturing images\n"
" 'u' - switch undistortion on/off\n";
static void help()
{
printf( "This is a camera calibration sample.\n"
"Usage: calibration\n"
" -w <board_width> # the number of inner corners per one of board dimension\n"
" -h <board_height> # the number of inner corners per another board dimension\n"
" [-pt <pattern>] # the type of pattern: chessboard or circles' grid\n"
" [-n <number_of_frames>] # the number of frames to use for calibration\n"
" # (if not specified, it will be set to the number\n"
" # of board views actually available)\n"
" [-d <delay>] # a minimum delay in ms between subsequent attempts to capture a next view\n"
" # (used only for video capturing)\n"
" [-s <squareSize>] # square size in some user-defined units (1 by default)\n"
" [-o <out_camera_params>] # the output filename for intrinsic [and extrinsic] parameters\n"
" [-op] # write detected feature points\n"
" [-oe] # write extrinsic parameters\n"
" [-zt] # assume zero tangential distortion\n"
" [-a <aspectRatio>] # fix aspect ratio (fx/fy)\n"
" [-p] # fix the principal point at the center\n"
" [-v] # flip the captured images around the horizontal axis\n"
" [-V] # use a video file, and not an image list, uses\n"
" # [input_data] string for the video file name\n"
" [-su] # show undistorted images after calibration\n"
" [input_data] # input data, one of the following:\n"
" # - text file with a list of the images of the board\n"
" # the text file can be generated with imagelist_creator\n"
" # - name of video file with a video of the board\n"
" # if input_data not specified, a live view from the camera is used\n"
"\n" );
printf("\n%s",usage);
printf( "\n%s", liveCaptureHelp );
}
enum { DETECTION = 0, CAPTURING = 1, CALIBRATED = 2 };
enum Pattern { CHESSBOARD, CIRCLES_GRID, ASYMMETRIC_CIRCLES_GRID };
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), NORM_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 calcChessboardCorners(Size boardSize, float squareSize, vector<Point3f>& corners, Pattern patternType = CHESSBOARD)
{
corners.resize(0);
switch(patternType)
{
case CHESSBOARD:
case 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 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:
CV_Error(Error::StsBadArg, "Unknown pattern type\n");
}
}
static bool runCalibration( vector<vector<Point2f> > imagePoints,
Size imageSize, Size boardSize, Pattern patternType,
float squareSize, float aspectRatio,
int flags, Mat& cameraMatrix, Mat& distCoeffs,
vector<Mat>& rvecs, vector<Mat>& tvecs,
vector<float>& reprojErrs,
double& totalAvgErr)
{
cameraMatrix = Mat::eye(3, 3, CV_64F);
if( flags & CALIB_FIX_ASPECT_RATIO )
cameraMatrix.at<double>(0,0) = aspectRatio;
distCoeffs = Mat::zeros(8, 1, CV_64F);
vector<vector<Point3f> > objectPoints(1);
calcChessboardCorners(boardSize, squareSize, objectPoints[0], patternType);
objectPoints.resize(imagePoints.size(),objectPoints[0]);
double rms = calibrateCamera(objectPoints, imagePoints, imageSize, cameraMatrix,
distCoeffs, rvecs, tvecs, flags|CALIB_FIX_K4|CALIB_FIX_K5);
printf("RMS error reported by calibrateCamera: %g\n", rms);
bool ok = checkRange(cameraMatrix) && checkRange(distCoeffs);
totalAvgErr = computeReprojectionErrors(objectPoints, imagePoints,
rvecs, tvecs, cameraMatrix, distCoeffs, reprojErrs);
return ok;
}
static void saveCameraParams( const string& filename,
Size imageSize, Size boardSize,
float squareSize, float aspectRatio, int flags,
const Mat& cameraMatrix, const Mat& distCoeffs,
const vector<Mat>& rvecs, const vector<Mat>& tvecs,
const vector<float>& reprojErrs,
const vector<vector<Point2f> >& imagePoints,
double totalAvgErr )
{
FileStorage fs( filename, FileStorage::WRITE );
time_t tt;
time( &tt );
struct tm *t2 = localtime( &tt );
char buf[1024];
strftime( buf, sizeof(buf)-1, "%c", t2 );
fs << "calibration_time" << buf;
if( !rvecs.empty() || !reprojErrs.empty() )
fs << "nframes" << (int)std::max(rvecs.size(), reprojErrs.size());
fs << "image_width" << imageSize.width;
fs << "image_height" << imageSize.height;
fs << "board_width" << boardSize.width;
fs << "board_height" << boardSize.height;
fs << "square_size" << squareSize;
if( flags & CALIB_FIX_ASPECT_RATIO )
fs << "aspectRatio" << aspectRatio;
if( flags != 0 )
{
sprintf( buf, "flags: %s%s%s%s",
flags & CALIB_USE_INTRINSIC_GUESS ? "+use_intrinsic_guess" : "",
flags & CALIB_FIX_ASPECT_RATIO ? "+fix_aspectRatio" : "",
flags & CALIB_FIX_PRINCIPAL_POINT ? "+fix_principal_point" : "",
flags & CALIB_ZERO_TANGENT_DIST ? "+zero_tangent_dist" : "" );
}
fs << "flags" << flags;
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);
r = rvecs[i].t();
t = tvecs[i].t();
}
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;
}
}
static bool readStringList( const string& filename, vector<string>& l )
{
l.resize(0);
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;
}
static bool runAndSave(const string& outputFilename,
const vector<vector<Point2f> >& imagePoints,
Size imageSize, Size boardSize, Pattern patternType, float squareSize,
float aspectRatio, int flags, Mat& cameraMatrix,
Mat& distCoeffs, bool writeExtrinsics, bool writePoints )
{
vector<Mat> rvecs, tvecs;
vector<float> reprojErrs;
double totalAvgErr = 0;
bool ok = runCalibration(imagePoints, imageSize, boardSize, patternType, squareSize,
aspectRatio, flags, cameraMatrix, distCoeffs,
rvecs, tvecs, reprojErrs, totalAvgErr);
printf("%s. avg reprojection error = %.2f\n",
ok ? "Calibration succeeded" : "Calibration failed",
totalAvgErr);
if( ok )
saveCameraParams( outputFilename, imageSize,
boardSize, squareSize, aspectRatio,
flags, cameraMatrix, distCoeffs,
writeExtrinsics ? rvecs : vector<Mat>(),
writeExtrinsics ? tvecs : vector<Mat>(),
writeExtrinsics ? reprojErrs : vector<float>(),
writePoints ? imagePoints : vector<vector<Point2f> >(),
totalAvgErr );
return ok;
}
int main( int argc, char** argv )
{
Size boardSize, imageSize;
float squareSize = 1.f, aspectRatio = 1.f;
Mat cameraMatrix, distCoeffs;
const char* outputFilename = "out_camera_data.yml";
const char* inputFilename = 0;
int i, nframes = 10;
bool writeExtrinsics = false, writePoints = false;
bool undistortImage = false;
int flags = 0;
VideoCapture capture;
bool flipVertical = false;
bool showUndistorted = false;
bool videofile = false;
int delay = 1000;
clock_t prevTimestamp = 0;
int mode = DETECTION;
int cameraId = 0;
vector<vector<Point2f> > imagePoints;
vector<string> imageList;
Pattern pattern = CHESSBOARD;
if( argc < 2 )
{
help();
return 0;
}
for( i = 1; i < argc; i++ )
{
const char* s = argv[i];
if( strcmp( s, "-w" ) == 0 )
{
if( sscanf( argv[++i], "%u", &boardSize.width ) != 1 || boardSize.width <= 0 )
return fprintf( stderr, "Invalid board width\n" ), -1;
}
else if( strcmp( s, "-h" ) == 0 )
{
if( sscanf( argv[++i], "%u", &boardSize.height ) != 1 || boardSize.height <= 0 )
return fprintf( stderr, "Invalid board height\n" ), -1;
}
else if( strcmp( s, "-pt" ) == 0 )
{
i++;
if( !strcmp( argv[i], "circles" ) )
pattern = CIRCLES_GRID;
else if( !strcmp( argv[i], "acircles" ) )
pattern = ASYMMETRIC_CIRCLES_GRID;
else if( !strcmp( argv[i], "chessboard" ) )
pattern = CHESSBOARD;
else
return fprintf( stderr, "Invalid pattern type: must be chessboard or circles\n" ), -1;
}
else if( strcmp( s, "-s" ) == 0 )
{
if( sscanf( argv[++i], "%f", &squareSize ) != 1 || squareSize <= 0 )
return fprintf( stderr, "Invalid board square width\n" ), -1;
}
else if( strcmp( s, "-n" ) == 0 )
{
if( sscanf( argv[++i], "%u", &nframes ) != 1 || nframes <= 3 )
return printf("Invalid number of images\n" ), -1;
}
else if( strcmp( s, "-a" ) == 0 )
{
if( sscanf( argv[++i], "%f", &aspectRatio ) != 1 || aspectRatio <= 0 )
return printf("Invalid aspect ratio\n" ), -1;
flags |= CALIB_FIX_ASPECT_RATIO;
}
else if( strcmp( s, "-d" ) == 0 )
{
if( sscanf( argv[++i], "%u", &delay ) != 1 || delay <= 0 )
return printf("Invalid delay\n" ), -1;
}
else if( strcmp( s, "-op" ) == 0 )
{
writePoints = true;
}
else if( strcmp( s, "-oe" ) == 0 )
{
writeExtrinsics = true;
}
else if( strcmp( s, "-zt" ) == 0 )
{
flags |= CALIB_ZERO_TANGENT_DIST;
}
else if( strcmp( s, "-p" ) == 0 )
{
flags |= CALIB_FIX_PRINCIPAL_POINT;
}
else if( strcmp( s, "-v" ) == 0 )
{
flipVertical = true;
}
else if( strcmp( s, "-V" ) == 0 )
{
videofile = true;
}
else if( strcmp( s, "-o" ) == 0 )
{
outputFilename = argv[++i];
}
else if( strcmp( s, "-su" ) == 0 )
{
showUndistorted = true;
}
else if( s[0] != '-' )
{
if( isdigit(s[0]) )
sscanf(s, "%d", &cameraId);
else
inputFilename = s;
}
else
return fprintf( stderr, "Unknown option %s", s ), -1;
}
if( inputFilename )
{
if( !videofile && readStringList(inputFilename, imageList) )
mode = CAPTURING;
else
capture.open(inputFilename);
}
else
capture.open(cameraId);
if( !capture.isOpened() && imageList.empty() )
return fprintf( stderr, "Could not initialize video (%d) capture\n",cameraId ), -2;
if( !imageList.empty() )
nframes = (int)imageList.size();
if( capture.isOpened() )
printf( "%s", liveCaptureHelp );
namedWindow( "Image View", 1 );
for(i = 0;;i++)
{
Mat view, viewGray;
bool blink = false;
if( capture.isOpened() )
{
Mat view0;
capture >> view0;
view0.copyTo(view);
}
else if( i < (int)imageList.size() )
view = imread(imageList[i], 1);
if(view.empty())
{
if( imagePoints.size() > 0 )
runAndSave(outputFilename, imagePoints, imageSize,
boardSize, pattern, squareSize, aspectRatio,
flags, cameraMatrix, distCoeffs,
writeExtrinsics, writePoints);
break;
}
imageSize = view.size();
if( flipVertical )
flip( view, view, 0 );
vector<Point2f> pointbuf;
cvtColor(view, viewGray, COLOR_BGR2GRAY);
bool found;
switch( pattern )
{
case CHESSBOARD:
found = findChessboardCorners( view, boardSize, pointbuf,
CALIB_CB_ADAPTIVE_THRESH | CALIB_CB_FAST_CHECK | CALIB_CB_NORMALIZE_IMAGE);
break;
case CIRCLES_GRID:
found = findCirclesGrid( view, boardSize, pointbuf );
break;
case ASYMMETRIC_CIRCLES_GRID:
found = findCirclesGrid( view, boardSize, pointbuf, CALIB_CB_ASYMMETRIC_GRID );
break;
default:
return fprintf( stderr, "Unknown pattern type\n" ), -1;
}
if( pattern == CHESSBOARD && found) cornerSubPix( viewGray, pointbuf, Size(11,11),
Size(-1,-1), TermCriteria( TermCriteria::EPS+TermCriteria::COUNT, 30, 0.1 ));
if( mode == CAPTURING && found &&
(!capture.isOpened() || clock() - prevTimestamp > delay*1e-3*CLOCKS_PER_SEC) )
{
imagePoints.push_back(pointbuf);
prevTimestamp = clock();
blink = capture.isOpened();
}
if(found)
drawChessboardCorners( view, boardSize, Mat(pointbuf), found );
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(undistortImage)
msg = format( "%d/%d Undist", (int)imagePoints.size(), nframes );
else
msg = format( "%d/%d", (int)imagePoints.size(), nframes );
}
putText( view, msg, textOrigin, 1, 1,
mode != CALIBRATED ? Scalar(0,0,255) : Scalar(0,255,0));
if( blink )
bitwise_not(view, view);
if( mode == CALIBRATED && undistortImage )
{
Mat temp = view.clone();
undistort(temp, view, cameraMatrix, distCoeffs);
}
imshow("Image View", view);
int key = 0xff & waitKey(capture.isOpened() ? 50 : 500);
if( (key & 255) == 27 )
break;
if( key == 'u' && mode == CALIBRATED )
undistortImage = !undistortImage;
if( capture.isOpened() && key == 'g' )
{
mode = CAPTURING;
imagePoints.clear();
}
if( mode == CAPTURING && imagePoints.size() >= (unsigned)nframes )
{
if( runAndSave(outputFilename, imagePoints, imageSize,
boardSize, pattern, squareSize, aspectRatio,
flags, cameraMatrix, distCoeffs,
writeExtrinsics, writePoints))
mode = CALIBRATED;
else
mode = DETECTION;
if( !capture.isOpened() )
break;
}
}
if( !capture.isOpened() && showUndistorted )
{
Mat view, rview, map1, map2;
initUndistortRectifyMap(cameraMatrix, distCoeffs, Mat(),
getOptimalNewCameraMatrix(cameraMatrix, distCoeffs, imageSize, 1, imageSize, 0),
imageSize, CV_16SC2, map1, map2);
for( i = 0; i < (int)imageList.size(); i++ )
{
view = imread(imageList[i], 1);
if(view.empty())
continue;
remap(view, rview, map1, map2, INTER_LINEAR);
imshow("Image View", rview);
int c = 0xff & waitKey();
if( (c & 255) == 27 || c == 'q' || c == 'Q' )
break;
}
}
return 0;
}