Usage: imupsam n input_image output_image
* Upsamples the input 2D image by a factor of n and
writes result into output_image; n must be an
integer in the range 2..30.
* 7th order polynomial interpolation is used in each
direction.
* Inputs can be complex, float, short, PGM, or PPM.
* Author: RW Cox -- 16 April 1999.