Only mask elements of some value with conv2
1 vue (au cours des 30 derniers jours)
Afficher commentaires plus anciens
I want to use convolution, or something like convolution, to perform sum over neighboring elements. So normally I could use
x=zeros(20,20);
r=randi(1000,size(x));
mask=[ 0 0 1 1 1 0 0
0 1 1 1 1 1 0
1 1 1 1 1 1 1
1 1 1 1 1 1 1
1 1 1 1 1 1 1
0 1 1 1 1 1 0
0 0 1 1 1 0 0];
myconv=conv2(r,mask);
However, I only want the mask to add elements with the same value as the reference element (center of the mask). How can this be done? Thanks!
Note: this would be easy if there were only a few possible values, but I want it to work for many possible values in the matrix r.
0 commentaires
Réponse acceptée
Matt J
le 6 Oct 2014
Modifié(e) : Matt J
le 6 Oct 2014
How about this?
[N,N]=size(mask);
vals=im2col(r,[N,N],'sliding');
ref=vals((N^2+1)/2, :); %assumes odd-dimensions of mask
result=mask(:).' * (vals.*bsxfun(@eq,vals, ref ));
result=reshape(result,size(r)-N+1);
It's a modification of conv2(...'valid'). If you wanted conv2(...,'full'), you would simply have to pre-pad r with zeros.
Plus de réponses (0)
Voir également
Catégories
En savoir plus sur Logical dans Help Center et File Exchange
Produits
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!