OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Wed, 11 Nov 2020 09:54:01 -0600line extension beyond 2 points how to extrapolatehttp://answers.opencv.org/question/237676/line-extension-beyond-2-points-how-to-extrapolate/ No prob with this:
cv::line(color_img, points[0], points[1], Scalar(255, 255, 255), 1, LINE_8, 0);
How can I extend the line beyond each point(s). A different OpenCV fx?
superflyWed, 11 Nov 2020 09:54:01 -0600http://answers.opencv.org/question/237676/Arranging Contour Points in Clockwise orderhttp://answers.opencv.org/question/200092/arranging-contour-points-in-clockwise-order/ Hi to everyone.
I would like to know possibilities of sorting the single contour points in the clockwise order based on the center of the contour.
Please suggest.balasubramaniyan94Tue, 25 Sep 2018 10:12:47 -0500http://answers.opencv.org/question/200092/projectPoints() Wrong results??http://answers.opencv.org/question/175542/projectpoints-wrong-results/Why is my code snippet giving me weird results for projected points?
//Generate the one 3D Point which i want to project onto 2D plane
vector<Point3d> points_3d;
points_3d.push_back(Point3d(10, 10, 100));
Mat points3d = Mat(points_3d);
//Generate the identity matrix and zero vector for rotation matrix and translation vector
Mat rvec = (Mat_<double>(3, 3) << (1, 0, 0, 0, 1, 0, 0, 0, 1));
Mat tvec = (Mat_<double>(3, 1) << (0, 0, 0));
//Generate a camera intrinsic matrix
Mat K = (Mat_<double>(3,3)
<< (1000, 0, 50,
0, 1000, 50,
0, 0, 1));
//Project the 3D Point onto 2D plane
Mat points_2d;
projectPoints(points_3d, rvec, tvec, K, Mat(), points_2d);
//Output
cout << points_2d;
I get as projected 2D Point
points_2d = (-1.708699427820658e+024, -9.673395654445999e-026)
If i calculate it on a paper on my own, i'm expecting a point points_2d = (150, 150) with that formula: ![image description](/upfiles/15069441372411866.png)mirnyyMon, 02 Oct 2017 06:23:27 -0500http://answers.opencv.org/question/175542/Undistor algorithm on OpenCVhttp://answers.opencv.org/question/67066/undistor-algorithm-on-opencv/ Hello,
I would like to get more information about undistor algorithm used on OpenCV.
Here is the source of the program:
https://github.com/Itseez/opencv/blob/master/modules/imgproc/src/undistort.cpp
Where could I get paper on the algorithm used for undistor points?
Best regard.xavier12358Sun, 26 Jul 2015 11:14:18 -0500http://answers.opencv.org/question/67066/multiply two points and matrixhttp://answers.opencv.org/question/915/multiply-two-points-and-matrix/I want to multiply two points and matrix.I have trainPoints which is trained before the program.And I have testPoints which is occured while program is processing.And also I have homography which is Mat object (calculated with findHomography method).I want to check is it true?I want to calculate homography error.How can i multiply two points and homography?basarkirMon, 30 Jul 2012 09:08:40 -0500http://answers.opencv.org/question/915/