Re: Zerocrossings in an image

[Etienne Grossmann]

Hth

f = 2*kron (randn(4)>0,ones(4))-1

z0 = f<0;                 ## Negative
[R,C] = size(f);
z = zeros(R,C);
z(1:R-1,:) |= z0(2:R,:);  ## Grow
z(2:R,:) |= z0(1:R-1,:);
z(:,1:C-1) |= z0(:,2:C);
z(:,2:C) |= z0(:,1:C-1);

z &= !z0                  ## "Positive zero-crossings"?



On Sun, Apr 17, 2005 at 06:02:02PM +0200, Søren Hauberg wrote:
# Hi
# Does anybody here know a simple way to find the zerocrossings in an 
# image in Octave?
# I usually do something like this (where f is the image (or 2d function))
# 
# zerocrossings = bwmorph(f>=0, "remove");
# 
# but then I depend on bwmorph which only is octave-forge (which I don't 
# have at school).
# 
# Any help would be great,
# \Søren
# 
# 
# 
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-- 
Etienne Grossmann ------ http://www.cs.uky.edu/~etienne



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