OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Mon, 20 May 2019 22:10:34 -0500I have system with three camera. I have R and T matrix between C1 & C2 also between C2 & C3. How to transform a point from first camera to third camera?http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/I have three cameras (C1, C2, C3). I have calibrated C1 & C2 as one stereo pair(System-1) and C2 & C3 (System-2) as another stereo pair. So in results, I have rotational and translation matrix between C1 & C2 also C2 & C3. After successful reconstruction, I have one 3D point say P(X, Y, Z) using system-1. So my question is how to transform Point P in all three cameras?Wed, 15 May 2019 15:50:52 -0500http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/Answer by balala for <p>I have three cameras (C1, C2, C3). I have calibrated C1 & C2 as one stereo pair(System-1) and C2 & C3 (System-2) as another stereo pair. So in results, I have rotational and translation matrix between C1 & C2 also C2 & C3. After successful reconstruction, I have one 3D point say P(X, Y, Z) using system-1. So my question is how to transform Point P in all three cameras?</p>
http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/?answer=213232#post-id-213232C1 = R1 * C2 + T1;
C2 = R2 * C3 + T2;
C1 = R1*（R2 * C3 + T2）+T1;
C3 to C1：C1 = R1 * R2 * C3 + R1 * T2+ T1;
the final transform:`R = R1 * R2,T = R1 * T2+ T1;`
of course you should know OpenCV's RT rule.Mon, 20 May 2019 22:10:34 -0500http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/?answer=213232#post-id-213232Answer by Tetragramm for <p>I have three cameras (C1, C2, C3). I have calibrated C1 & C2 as one stereo pair(System-1) and C2 & C3 (System-2) as another stereo pair. So in results, I have rotational and translation matrix between C1 & C2 also C2 & C3. After successful reconstruction, I have one 3D point say P(X, Y, Z) using system-1. So my question is how to transform Point P in all three cameras?</p>
http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/?answer=213142#post-id-213142OpenCV provides the [ComposeRT](https://docs.opencv.org/4.1.0/d9/d0c/group__calib3d.html#ga044b03d81f99370db05c52c3d0b46599) function, which combines two sets of Rotation and Translation transforms.Sat, 18 May 2019 09:40:26 -0500http://answers.opencv.org/question/212998/i-have-system-with-three-camera-i-have-r-and-t-matrix-between-c1-c2-also-between-c2-c3-how-to-transform-a-point-from-first-camera-to-third-camera/?answer=213142#post-id-213142