1. A system for generating an interpolated value at a first interpolation point between two central source points of a set of four source points, the four source points aligned along a first direction, each source point having a value, the system comprising: a processing unit configured to calculate the interpolated value as: 
 f 0 ( a )= a 0 a 3 +b 0 a 2 +c 0 a+d 0 wherein [ a 0 b 0 c 0 d 0 ] = Q [ y - 1 y 0 y 1 y 2 ] , wherein: y −1 is a value of a second-nearest source point in a first direction parallel to a first image axis; y 0 is a value of a nearest source point in the first direction; y 1 is a value of a nearest source point in a second direction opposite the first direction and parallel to the first image axis; y 2 is a value of a second-nearest source point in the second direction; a is the ratio of: the distance between the first interpolation point and the nearest source point in the first direction; to the distance between the nearest source point in the first direction and the nearest source point in the second direction; and Q is substantially equal to [ - 0.3333 1 - 1 0.3333 0.8 - 1.8 1.2 - 0.2 - 0.4667 - 0.2 0.8 - 0.1333 0 1 0 0 ] .