# Can anyone help me solve this problem?

• Nov 28th 2008, 04:58 AM
dave_s_lyne
Can anyone help me solve this problem?
Can anyone help me solve this problem?

It probably involves trigonometry but not exclusively....

I have three known world-space xyz points located on a plane. All three of these points are visible to the camera.
The cameras frustum is known and the locations in the cameras pixel space of each of the three points of
the plane are also known.

From this information is it possible to calculate the transformation matrix of the plane? I can only think of an
iterative method that doesn't seem very robust.

• Nov 28th 2008, 06:50 AM
dave_s_lyne
I'll go into a little more detail to explain exactly what I'm trying to achieve.

Firstly, the camera that I mention is actually a real camera (A canon G9 camera that I'm operating remotely)

I know the focal length of the camera so basically I can work out the perspective matrix of the camera (theres also
a bit of lens distortion but its not too bad).

The camera is located anywhere in the room but is always facing the inside of a sphere. My problem is that I need
to calculate the location of the camera in relation to the centre of the sphere.

In order to calculate this I figure that I need to physically mark three arbitary points on the inside of
the sphere that the camera can see. I can measure the XYZ locations of each of these points relative
to spheres centre.

The resulting camera position would be a best-fit solution.