Region Adjacency Graph giving no output...

[lacan]

Hi, I would like to use the Region Adjacency Graph Plugin, which says works on labelled images. However I fail to get any data out of it.

If I run this imageJ macro code

run("Blobs (25K)");
setAutoThreshold("Default");
run("Analyze Particles...", "  show=Masks");
run("Connected Components Labeling", "connectivity=4 type=[8 bits]");
run("Region Adjacency Graph", "  image=blobs.gif");

The results table is empty

[dlegland]

Hi,
this is not really a bug. In this sample image, the blobs do not touch each other, and hence are not adjacent. Therefore, an empty output is normal...

To have an adjacency result, one possibility is to compute the influence region of each blob, using for example watershed on the distance transform.

run("Blobs (25K)");
setAutoThreshold("Default");
//run("Threshold...");
//setThreshold(126, 255);
setOption("BlackBackground", false);
run("Convert to Mask");
run("Close");
run("Invert");
run("Chamfer Distance Map", "distances=[Borgefors (3,4)] output=[32 bits] normalize");
run("Classic Watershed", "input=blobs-dist mask=None min=0 max=255");
run("Region Adjacency Graph", "show image=blobs.gif");
selectWindow("blobs.gif");

Hope this helps?

[lacan]

Hi,

Thanks for the heads up! I see now that you expect the regions to be touching. Thing is I would have expected it to work by first computing a voronoi diagram (which is what you did) and that it was then simply measuring the distance of each particle to its delaunay neighbors.

But not I see that I need to add that extra step myself. Thanks so much. I did almost the same but passed by the voronoi diagram.

run("Blobs (25K)");
setAutoThreshold("Default");
//run("Threshold...");
//setThreshold(126, 255);
setOption("BlackBackground", false);
run("Convert to Mask");
run("Voronoi");
setThreshold(0, 1);
setOption("BlackBackground", true);
run("Convert to Mask");
run("Connected Components Labeling", "connectivity=4 type=[8 bits]");

run("Region Adjacency Graph", "show image=blobs.gif");
selectWindow("blobs.gif");