- The projective camera
has a rank 3 whereas it has 4 columns.
Clearly, it has a on dimensional right null space. Suppose the null space is generated by the 4-vector
, that is
**Claim:**is the optical center of the camera .*Proof*. Consider the line containing and any other point in 3-space. Points on this line can be represented as- Writing
- An image point
defines a line
in 3-space: