crossing
[ XITE Reference Manual | XITE home ]
Name
crossing - find zero crossing or any other crossing
Syntax
crossing [-t <t>] <inimage> <outimage>
Description
Can be used to find zero crossing of second derivative,
laplace. Can also be used to determine any other kind
of crossing. Pixels below or equal to t are set if the pixel
to the right or below is above t, pixels above t are
set if the pixel to the right or below is below or equal to
t. Pixels that are "set" are set to the maximum absolute
difference of the two neighbours, to indicate the strength
of the edge.
IF (crossing t)
out(x,y) = MAX(ABS(in(x,y)-in(x+1,y)),
ABS(in(x,y)-in(x,y+1)))
ELSE
out(x,y) = 0
Restrictions
inimage must have bands with pixel type unsigned byte.
Options
-
-t t
- Crossing value. Default is 127.
See also
crossing(3), contour(1)
Author
Tor Lønnestad, BLAB, Ifi, UiO
Examples
crossing -t 100 mona.img monacross.img
Id
$Id: crossing.c,v 1.24 1997/01/16 15:53:28 svein Exp $