affine

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Name

affine - affine geometric transform

Syntax

 #include <xite/geometry.h>

 int affine( IBAND inband, IBAND outband,
    double x0, double x1, double x2, double y0,
    double y1, double y2, int ip, int bg );

Description

affine performs a linear transform of the coordinate system (x, y) to another coordinate system (u,v) All coordinates are adjusted acording to (xstart, ystart). 
 outband(x,y) = inband(u,v)
 u = x0 + x1 * x + x2 * y
 v = y0 + y1 * x + y2 * y
The interpolation method ip is 
  0 : Nearest neighbor
  1 : Bilinear   interpolation
      g(x) = bi(f(x), f(x+1), d)
      bi(x, y, d) = x(1-d) + yd
  3 ; Cubic      interpolation
      g(x) = cc(f(x-1), f(x), f(x+1), f(x+2), d)
      cc(x, y, z, v, d) = y + d((-x+z) +
             d((2x-2y+z-v) + d(-x+y-z+v)))

bg gives the background pixel value.

Restrictions

inband and outband must have pixel type unsigned byte.

Return value

 0 : Ok
 1 : Bad input or output pixel type

Reference

Wayne Niblack. Digital Image Processing, p 131-150

See also

affine(1), quadratic(3), rotate(3), shift_band(3), transpose_band(3)

Author

Otto Milvang

Id

$Id: affine.c,v 1.32 1997/05/29 16:33:09 svein Exp $