Hi,

I have two simultaneous videos from two cameras that are looking at a ball moving around at a table.

I do tracking on the cameras so I know where the ball is when it is in the frames.

I would like to estimate the the balls position, but to do so I first need the cameras positions and rotation matrix.

I guess I have around 50 frames where the ball is detected on both cameras.

Is that possible with only one marker, or do I need to add more markers.

Kind regards

Jesper

The more data points you have the better. Also, make sure that the markers are spread out enough across the camera's field of view to make the readings more reliable. I think four markers, spread apart as a quadrilateral as far as you can and still be seen by the cameras should work pretty well.

I would like to estimate the the balls position, but to do so I first need the cameras positions and rotation matrix.

I guess I have around 50 frames where the ball is detected on both cameras.

Is that possible with only one marker, or do I need to add more markers.

If I understanad corectly, ball is the only tracked marker, and for establishing its position corectly by being observed by both of the cameras at a time at every frame, all you should need to establish position of the ball in 3d should be:

- distance of cameras from eachother (absolute value, able to scale relative later)

- direction vector of cameras along with the up vector, or, a single quaternion (direction vector with angle around the direction)

this is all the data necesary to establish 3d position of ball visible from two cameras always at a time, knowing raletive defintion of the two cameras.

Last thing to define would be projection of cameras, what I expect to be 90 degrees FOV of certain ratio.