MATLAB: How to use “gplot” function

2dgraphimage processingMATLABplot

Hey Every body;
I want to graph a matrix using "gplot" function, i had get the each object boundary in the image using the following:
[B L N A]=bwboundaries(bw,'noholes');
through that function i got 4 output: L for label matrix / N is no. of object found/ A is adjacent matrix…
To graph that labeled image i have 2 thoughts :
1- consider each boundray as a separate matrix a get it's coordinates and plot
as follow
               [i j]=find(cell2mat(B(2,:));
               gplot(B(2,:), [i j]);
but the result is a separate straight line!!
2- consider each connected component in the labeled matrix as anode then get it's coordinate and plot graph connecting those nodes
(i think that the second option is more reliable but i don't know how to implement regarding my poor )
Thanks A lot

Best Answer

I assume you want to plot based on the adjacency matrix A? You'll have to figure out exactly how to define an objects coordinates... an edge point? The centroid?
In the example below, I've just chosen the first point of each boundary. Is this similar to what you're looking for?
 BW = imread('blobs.png');
 [B, L, N, A] = bwboundaries(BW,'noholes');
 xy = cell2mat(cellfun(@(x) [x(1,2) x(1,1)], B, 'uni', 0));
 figure;
 imshow(BW) 
 hold on
 plot(xy(:,1), xy(:,2), 'b.')
 gplot(A, xy, 'r');
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