Theoretiker's profile - activity

So you basically invert the pinhole camera equation and find out s such that the ray intersects with the z = 0 plane?

calibrationMatrixValues and Pythagoean theorem?

@theodore: As far as I have understood one needs solvePnP() to get the position and angle of the camera in world coordinates. Once one has this, how does this function help? I am currently thinking about taking a random point on the plane and project it to the image and then iteratively see which points is closest to the given image point.

I'd be interested in this as well. I need to know which ray each point on the image corresponds to. Basically I would apply the answer to your question twice for the front and back plane of the box I look at the connect them. Your question should be answerable with a bit of linear algebra if one neglects the curvature. I'll play around in Mathematica in the meanwhile.

I have calibration images that show the 3D vertices of a semi-transparent cube. There is only one image per camera, though. Since initCameraMatrix2D only supports 2D calibration patterns from different angles I tool the six faces of the cube as patterns and set the last coordinate to zero. This gave me six sets of four points each. For two supposedly similar cameras, I got a focal length that differed by a factor 6.

When I have an image of a 2D calibration pattern right from the top, is there any way the calibration can work? I figured that in this particular case, only the ratio f/z can be computed, but not f individually if the camera position is not known (which I do not know). So I do need an image from the calibration pattern from an off angle to get some information about the focal length, right?

Is there something I did wrong with the calibration using the data that I have?