Projection equation
•The projection matrix models the cumulative effect of all parameters
•Useful to decompose into a series of operations
projection
intrinsics
rotation
translation
identity matrix
Camera parameters
A camera is described by several parameters
•Translation T of the optical center from the origin of world coords
•Rotation R of the image plane
•focal length f, principle point (x’c, y’c), pixel size (sx, sy)
•blue parameters are called “extrinsics,”  red are “intrinsics”
•The definitions of these parameters are not completely standardized
–especially intrinsics—varies from one book to another