2016-02-25 09:50:06 -0600 received badge ● Editor (source) 2016-02-25 09:39:13 -0600 asked a question Rodrigues giving empty Matrix Hi, I'm implementing markerbased tracking on Android and I'm stuck at the rotation matrix. Up until the solvePnP everything works fine and I get results (rvec, tvec) that seem legit. But after using the rvec in Rodrigues for having a rotation matrix, it just results in a 3x3 Matrix, filled only with zeroes. I really don't get this, because there are definitely values in rvec, but Rodrigues just doesn't use them? I hope somebody knows whats wrong. Heres the code snippet: Mat rvec = new Mat(3,1,CvType.CV_64F); Mat tvec = new Mat(3,1,CvType.CV_64F); MatOfPoint3f markerPointsMat = new MatOfPoint3f(new Point3(0,0,0),new Point3(1,0,0),new Point3(1,1,0),new Point3(0,1,0)); MatOfPoint2f pointsMat = new MatOfPoint2f(points.get(0),points.get(1),points.get(2),points.get(3)); //cam matrix, by hand Mat cam=new Mat(3,3,CvType.CV_64F); cam.zeros(cam.size(),CvType.CV_64F); cam.put(0, 0, 1400.533595140377 ); cam.put(0, 2, 175.5 ); cam.put(1, 1, 1400.533595140377 ); cam.put(1, 2, 143.5); cam.put(2,2,1.0); double[] a = {0.1155606860709641,-0.3046292381782507,0,0,0}; MatOfDouble dist = new MatOfDouble(a); Calib3d.solvePnP(markerPointsMat, pointsMat, cam, dist, rvec, tvec); //rot vector to matrix Mat rmat = Mat.zeros(3,3,CvType.CV_64F); Rodrigues(rvec, rmat);