OpenCV Q&A Forum - RSS feedhttp://answers.opencv.org/questions/OpenCV answersenCopyright <a href="http://www.opencv.org">OpenCV foundation</a>, 2012-2018.Tue, 17 Apr 2018 02:59:28 -0500Understanding the Result of Camera Calibration and its Unitshttp://answers.opencv.org/question/189506/understanding-the-result-of-camera-calibration-and-its-units/ Hi,
I am quite new to camera calibration.
I have 35 images, based on the following functions :
findChessboardCorners()
cornerSubPix()
drawChessboardCorners()
calibrateCamera()
I now have
1. Camera Matrix - 3x3 dimension
2. Distortion Coefficient - 1x5 dimension
3. Rotation Vector - 35x3 dimension
4. Translation Vector - 35x3 dimension
Questions :
1. **camera matrix**
> [ 2421.70421334667, 0, 2138.107444179007;
> 0, 2429.244140012221, 1136.772764836856;
> 0, 0, 1]
In the above , what are the units of fx, fy , Cx and Cy ?
2. **Distortion Coefficient**
> [-0.2877455633196141,
> 0.2968104208806526, -0.001127291269463514, -0.002010576239298727, -0.3457992571078199]
Do we have any Units for K1, K2, P1, P2, K3 ?
3. **Rotation Vector**
> [-0.1019788539700399; 0.3918509002001774; 0.0734955967493143]
> [-0.1165422449849887; 0.5017699087572564; 0.4257284491781231]
> [-0.1233545118567792; 0.5922964766688477; 1.001270611741778]
> [-0.5253276710841507; -0.01653828323651414; -1.386034124708322]
> so on ... for all 35 images
What about the unit of Rotation Matrix? How should I understand it? What does this values mean?
4. **Translation Vector**
> [152.8348988935562, -168.8318694822206; 951.100836109663]
> [191.0103136141713; -207.2053481732149; 963.7313891311128]
> [307.0885175766131; -212.1491832662802; 945.4874998124949]
> [221.391205120318; -22.64308775049023; 910.7108013142725]
> so on ... for all 35 images
What about the unit of Translation Vector? How should I understand it ? What does its values mean?
I also tries the camera calibration app in Matlab, I set the same image but it does not show the same result? ThiyagaTue, 17 Apr 2018 02:59:28 -0500http://answers.opencv.org/question/189506/Rotation Matrix calculation using cvRodrigues , Calculating real world coordinates from pixel world coordinates .http://answers.opencv.org/question/14969/rotation-matrix-calculation-using-cvrodrigues-calculating-real-world-coordinates-from-pixel-world-coordinates/Hii I want to get real world (X,Y,Z) coordinates of an object from live capture from a PTZ camera .
I have found the intrinsic parameters , and using chessboard calibration with 15 chessboard images . I have also found the extrinsic prameters . I know Z coordinate cannot be found using a single camera .
To do this I need to find rotation and translation matrix . I have a doubt that for finding rotation matrix cvRodrigues() function will convert a rotation vector to 3x3 rotation matrix , but here I will have 15 rotation vectors . Which one should I use for finding the rotation matrix ??
Also I want to know if I happen to pan or tilt my camera from the original calibration position . will i have to recalculate my rotation matrix and translation matrix or can i use the old ones ?? sachin_rtTue, 11 Jun 2013 00:20:46 -0500http://answers.opencv.org/question/14969/