In the figure shown below, "'P1 "'refers to the first-step of the iterative reconstruction process, of the projection matrix "'P "'of the fan-beam geometry, which is constrained by the data fidelity term.
12.
In computer vision a "'camera matrix "'or "'( camera ) projection matrix "'is a 3 \ times 4 matrix which describes the mapping of a pinhole camera from 3D points in the world to 2D points in an image.
