RETRO (vipl) functions


LIBRARY ROUTINE

lvgettilt - computes the best-fit plane parameters for the input VIFF file

LIBRARY CALL

int lvfindtilt(
      xvimage *image,
      double *a,
      double *b,
      double *c)

INPUT

none

OUTPUT

none

RETURN VALUE

TRUE (1) on success, FALSE (0) on failure

DESCRIPTION

lvgettilt & lvfindtilt compute the least-squares best fit plane for an image. The plane will be given by f(x,y)=Ax+By+C with the tilt coefficients in inverse pixels.

lvmafdtilt computes the least-squares best fit plane for an image with a mask. The plane will be given by f(x,y)=Ax+By+C with the tilt coefficients in inverse pixels. The plane coefficients will be computed only for those pixels enabled by the mask image. If a mask image is supplied, it MUST be of the same type and size as the input image.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

If a mask image is supplied, it MUST be of the same type and size as the input image. The lvfindtilt and lvmafdtilt libraries will not work on BIT or COMPLEX data storage type files. lvfindtilt and lvmafdtilt will only calculate the tilt of the first band in a multiband image.

MODIFICATION

Mon Jun 11 16:30:29 MDT 1990 Donna Koechner - updated to ghostwriter Wed Mar 20 12:36:43 MET 1991 Jean Pierre Guerin 1- fixed loops to work right with non square images 2- fixed bogus (int) caste 3- fixed incorrect term in calculation of detc 4- corrected pointer increments 25-Sep-91 Scott Wilson - Changed (int) castes to (unsigned int) castes in byte processing loop - otherwise can get goofy sign extension problems. 25-Sep-91 Scott Wilson - Found that the det{A,B,C} eqns were ALL wrong. Fixed them up after rederiving the whole mess. 26-Sep-91 Scott Wilson - Fixed incorrect center point calculation.

FILES

$RETRO/objects/library/vipl/src/lvgettilt.c

SEE ALSO

vipl(3)

COPYRIGHT

Copyright (C) 1993 - 1997, Khoral Research, Inc. ("KRI") All rights reserved.