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calibrate_camera_opencv
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Fix interactive mode. Add comments

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Razvan Mihalyi 12 years ago
parent 7482fe9360
commit ac8cebae62
1 changed files with 71 additions and 39 deletions
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110
calibrate.cc
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@ -28,7 +28,7 @@ int main(int argc, char** argv)
else if (argc == 1)
{
user_mode = INTERACTIVE_MODE;
cout << "Camera calibration using interactive behavior. Press SPACE to grab frame.\n";
cout << "Camera calibration using interactive behavior. Press SPACE to grab frame, ESC to quit.\n";
}
else
{
@ -38,73 +38,105 @@ int main(int argc, char** argv)
cout << "Camera calibration using " << specified_boards << " frames.\n";
}
VideoCapture capture(-1); // open the default camera
VideoCapture capture(0); // open the default camera
if (!capture.isOpened()) // check if opening camera stream succeeded
{
cerr << "Camera could not be found. Exiting.\n";
return -1;
}
// set frame width and height by hand, defaults to 160x120
capture.set (CV_CAP_PROP_FRAME_WIDTH, 640);
capture.set (CV_CAP_PROP_FRAME_HEIGHT, 480);
// show camera image in a separate window
namedWindow("Camera Image", CV_WINDOW_KEEPRATIO);
// store object points (world coords) and image points (image coords) for use in calibrateCamera
vector< vector <Point3f> > object_points;
vector< vector <Point2f> > image_points;
Mat frame, gray_frame;
for(int count = 0; ; ++count)
/// current frame, its grayscale counterpart and storage for the first frame
Mat frame, gray_frame, first_frame;
// flag for determining whether pattern was detected in at least one of the camera grabs
bool acquired_samples = false;
// loop indefinitely and keep frame counter
for(int count_frames = 0; ; ++count_frames)
{
cout << "Frame: " << count << "\n";
capture >> frame; // get a new frame from camera
cvtColor(frame, gray_frame, CV_BGR2GRAY);
imshow("Camera Image", frame);
cvtColor(frame, gray_frame, CV_BGR2GRAY); // convert current frame to grayscale
imshow("Camera Image", frame); // update camera image
int key_pressed = waitKey(0);
int key_pressed = waitKey(0); // get user key press
if (key_pressed == KEY_CLOSE_WINDOW || key_pressed == KEY_ESCAPE) break;
if ((user_mode == INTERACTIVE_MODE && key_pressed == KEY_SPACE) ||
user_mode == PRESPECIFIED_MODE && count < specified_boards)
if (user_mode == INTERACTIVE_MODE && key_pressed == KEY_SPACE)
{
Size pattern_size(COUNT_SQUARES_X, COUNT_SQUARES_Y); //interior number of corners
vector<Point2f> corners; //this will be filled by the detected corners
Size pattern_size(COUNT_SQUARES_X, COUNT_SQUARES_Y); // number of squares in the pattern, a.k.a, interior number of corners
vector <Point2f> corners; // storage for the detected corners in findChessboardConrners
bool pattern_found = findChessboardCorners( gray_frame, pattern_size, corners, CALIB_CB_ADAPTIVE_THRESH + CALIB_CB_NORMALIZE_IMAGE + CALIB_CB_FAST_CHECK);
if (pattern_found) // to tweak params: http://bit.ly/QyoU3k
if (pattern_found)
{
cornerSubPix(gray_frame, corners, Size(11, 11), Size(-1, -1), TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 30, 0.1));
if (count_frames == 0) first_frame = frame;
// if corners are detected, they are further refined by calculating subpixel corners from the grayscale image
// this iterative process terminates after the given number of iterations and error epsilon
cornerSubPix(gray_frame, corners, Size(11, 11), Size(-1, -1), TermCriteria(CV_TERMCRIT_EPS + CV_TERMCRIT_ITER, 100, 0.1));
// draw the detected corners for debugging purposes
drawChessboardCorners(frame, pattern_size, Mat(corners), pattern_found);
// show detected corners in a different window
imshow("Detected pattern", frame);
vector< Point3f > obj;
// build a grid of 3D points (z component is 0 because the pattern is in one plane) to fit the square pattern area (COUNT_SQUARES_X * COUNT_SQUARES_Y)
vector< Point3f > pattern_points;
for(int j = 0; j < COUNT_SQUARES_X * COUNT_SQUARES_Y; ++j)
obj.push_back(Point3f(j/COUNT_SQUARES_X, j%COUNT_SQUARES_X, 0.0f));
pattern_points.push_back(Point3f(j/COUNT_SQUARES_X, j%COUNT_SQUARES_X, 0.0f));
// populate image points with corners and object points with grid points
image_points.push_back(corners);
object_points.push_back(obj);
cout << "Frame " << count << " grabbed.\n";
object_points.push_back(pattern_points);
cout << "Frame " << count_frames << " grabbed.\n";
acquired_samples = true;
}
}
}
Mat intrinsic = Mat(3, 3, CV_32FC1);
Mat distCoeffs;
vector<Mat> rvecs;
vector<Mat> tvecs;
calibrateCamera(object_points, image_points, frame.size(), intrinsic, distCoeffs, rvecs, tvecs);
Mat imageUndistorted;
while(1)
{
capture >> frame;
undistort(frame, imageUndistorted, intrinsic, distCoeffs);
imshow("win1", frame);
imshow("win2", imageUndistorted);
waitKey(1);
}
capture.release();
// if at least one video capture contains the pattern, perform calibration
if (acquired_samples)
{
Mat intrinsic = Mat(3, 3, CV_32FC1);
Mat distCoeffs;
vector<Mat> rvecs;
vector<Mat> tvecs;
// perform calibration, obtain instrinsic parameters and distortion coefficients
cout << "\nCalibrating...\n";
calibrateCamera(object_points, image_points, frame.size(), intrinsic, distCoeffs, rvecs, tvecs);
/*
Mat grab2 = imread("./data/grab2.jpg"), grab2_undistorted;
Mat grab4 = imread("./data/grab4.jpg"), grab4_undistorted;
undistort(grab2, grab2_undistorted, intrinsic, distCoeffs);
undistort(grab4, grab4_undistorted, intrinsic, distCoeffs);
imwrite("./data/grab2_undistorted.jpg", grab2_undistorted);
imwrite("./data/grab4_undistorted.jpg", grab4_undistorted);
*/
Mat undistorted_frame;
// apply the calibration transformation to the first frame and store image on disk
undistort(first_frame, undistorted_frame, intrinsic, distCoeffs);
imwrite("capture.jpg", first_frame);
imwrite("undistorted_frame.jpg", undistorted_frame);
cout << "Saved first frame to undistorted_frame.jpg\n";
cout << "Intrinsic parameters: \n" << intrinsic << "\n";
cout << "Distortion coefficients: \n" << distCoeffs << "\n";
}
else
{
cerr << "No frames grabbed!\n";
}
// the camera will be deinitialized automatically in VideoCapture destructor
return 0;
}

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