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frot

$ \bigcirc$Name


frot Rotate a Fimage using bilinear interpolation




$ \bigcirc$Command Synopsis


frot [-a a] [-b b] [-k] in out



-a a : rotation angle (in degrees, counterclockwise, default 0.0)

-b b : background grey value (default: 0.0)

-k : to keep original input image size (keep center position)

in : input Fimage

out : output Fimage




$ \bigcirc$Function Summary


void frot (in , out , a , b , k_flag )

Fimage in , out ;

float *a , *b ;

char *k_flag ;




$ \bigcirc$Description


This module will be removed in the next release. Please use fzrt instead.

x This module performs a rotation of angle a on a Fimage u(i, j), using a bilinear interpolation $ \tilde{{u}}$(x, y) of u(i, j) to compute the rotated image

u'(i, j) = $\displaystyle \tilde{{u}}$(  i cos a - j sin a  ,  i sin a + j cos a  ).

Since the rotated image must be included in a rectangular window, a black background (grey level 0.0) is set on the undefined parts of the rotated image. This background value can be modified through the - b option.

cm

Last, notice that that two successive rotations of angles a and a' are not equivalent to a single rotation of angle a + a', due to the the discrete representation of the images.

cm

NB: Calling this C-subroutine with in=out is not possible




$ \bigcirc$Version 1.0


Last Modification date : Thu Nov 29 20:23:56 2001


$ \bigcirc$Author


Lionel Moisan






next up previous contents index
Next: fsample Up: Reference Previous: fproj   Contents   Index
mw 2004-05-05