RETRO (vipl) functions


LIBRARY ROUTINE

lvenhance - Enhances an image using the local standard deviation and mean.

LIBRARY CALL

int lvenhance(
	xvimage *img,
	int xsize,
	int ysize,
	float factor,
	float minstd)

INPUT

OUTPUT

RETURN VALUE

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

DESCRIPTION

venhance uses a local transformation based on the mean and variance of the intensity maps and the intensity of the input image f(x,y) to create a new image g(x,y) by performing the following transformation at each pixel location (x,y):

g(x,y) = A(x,y).[f(x,y) -m(x,y)] + m(x,y),

where

A(x,y) = k . M / sigma(x,y) 0 < k < 1

where m(x,y) and sigma(x,y) are the gray-level mean and standard deviation computed in a neighborhood centered at (x,y), M is the global mean of f(x,y), and k is a constant in the range indicated above.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

lvenhance only operates on byte type images.

MODIFICATION

none

FILES

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

SEE ALSO

vipl(3)

COPYRIGHT

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