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186 8. Computer Vision in VR
Figure 8.1. Projecting a 2D ground plane onto a 2D viewing plane, where both planes
lie in 3D space.
where [X, Y , W ]
T
are the homogeneous image coordinates and [x, y, z, w]
T
are the homogeneous real-world coordinates. If you look at Figure 8.1 you
can see the plane P
2
on which the image is formed. The rays that lead from
the visible points in the scene back through the projection plane all con-
vergeonasinglepoint:the camera center. The projection plane is chosen as
indicated in Figure 8.1 because it is perpendicular to the principal axis, but
Figure 8.2. Different planes of projection may produce different images ...