IMAGE (kimage_proc) functions


LIBRARY ROUTINE

ligradient - perform image differentiation using gradient operator

LIBRARY CALL

int ligradient ( 
		 kobject src,
                 int gradient_type,
                 int operation_type,
                 kobject dest )

INPUT

OUTPUT

RETURN VALUE

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

DESCRIPTION

takes an image and performs the differentiation (high pass spatial filtering or edge enhancement) operation by using standard gradient operators. The standard gradient operators supported by ligradient are: Robert's, Sobel, Prewitt and Isotropic. The Robert's operators use a 2x2 kernel, whereas the other three use a 3x3 kernel. Each operator uses two templates to enhance edges in the horizontal and vertical directions only. For edge enhancements in other directions other operators should be used.

There are two approximations to the true gradient. The user can select between calculating the magnitude of the gradient by using squares and square roots (Euclidean distance evaluation), or by using absolute differences. The latter is computational faster.

Mask data is ignored.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

COMPLEX data processing is not supported

MODIFICATION

none

FILES

$IMAGE/objects/library/kimage_proc/src/ligradient.c

SEE ALSO

kimage_proc(3)

COPYRIGHT

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