how can i get the camera projection matrix out of calibrateCamera() return values

opencv triangulation camera-calibration
Srol picture Srol · Apr 19, 2013 · Viewed 19.4k times · Source

I am trying to get a 3x4 camera matrix for triangulation process but calibrateCamera() returns only 3x3 and 4x1 matrices.

How can i get the 3x4 out of those matrices?

Thanks in advance!!

Answer

Zhr Saghaie picture Zhr Saghaie · Oct 29, 2013

calibrateCamera() returns you
a 3x3 matrix as cameraMatrix,
a 4x1 matrix as distCoeffs, and rvecs and tvecs that are vectors of 3x1 rotation(R) and 3x1 transformation(t) matrices.

What you want is ProjectionMatrix, which is multiply [cameraMatrix] by [R|t]. 3D into 2D Projection

Therefore, it returs you a 3x4 ProjectionMatrix.
You can read OpenCV documentation for more info.

Related questions

How to correctly use cv::triangulatePoints()

I am trying to triangulate some points with OpenCV and I found this cv::triangulatePoints() function. The problem is that there is almost no documentation or examples of it. I have some doubts about it. What method does it use? …

Read More
How is the camera coordinate system in OpenCV oriented?

I'm trying to get the 3D coordinate of a point from the triangulation of two view. I'm not really sure if my results are correct or not. For example I'm not really sure if the sign of the coordinates are …

Read More
How to calculate 3D object points from 2D image points using stereo triangulation?

I have a stereo-calibrated camera system calibrated using OpenCV and Python. I am trying to use it to calculate the 3D position of image points. I have collected the intrinsic and extrinsic matrices, as well as, the E, F, R, …

Read More