RETRO (vipl) functions


LIBRARY ROUTINE

lvmarr - create the Marr Laplacian of Gaussian convolution kernel

LIBRARY CALL

int lvmarr (
	xvimage **image,
	int rows,
	int cols,
	float var)

INPUT

OUTPUT

RETURN VALUE

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

DESCRIPTION

This routine creates a convolution filter kernel using the following equation. pixel = [-1/(PI*var*var)]*[1-r*r/(2*var)]*exp[-r*r/(2*var)], where r is the calculated distance from the center of the kernel. A Marr filter is the Laplacian of a Gaussian, and is intended for high lighting image edges and at the same time smooth out the noise. vmarr creates image data of type float.

ADDITIONAL INFORMATION

none

EXAMPLES

none

SIDE EFFECTS

none

RESTRICTIONS

only generates float kernels

MODIFICATION

John Rasure, Marcelo Teran, Ramiro Jordan, Tom Sauer 7/12/89 - changed the Laplacian of a Gaussian operator. The new operator was taken from IEEE Transactions on Pattern Analysis and Machine Intelligence, Vol 11 No. 4, April 1989.

Jeremy Worley 7/02/90 - minor modifications to code so that it conforms to Khoros conventions. Added error check on kernel dimensions. No functional changes.

Robert Estes 4/25/90 - changed the code to implement a true Log

FILES

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

SEE ALSO

vipl(3)

COPYRIGHT

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