• The Homogeneous coordinate corresponding to the point (x,y,z) is the triple  (xh, yh, zh, w) where:                xh  =  wx                yh  =  wy            zh  =  wz We can (initially) set  w = 1. • Suppose a point  P = (x,y,z,1) in the homogeneous coordinate system is mapped to a point P' = (x',y',z’,1) by a transformations, then the transformation can be expressed in matrix form.