roipoly for multiple shapes
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I'm wanting to create multiple closed unconnected shapes using roipoly. I can do this fine for 2 shapes but when I add in the code for a 3rd shape it always connects the last coord of the 3rd shape to the first coord of the 1st shape.
if true
xmask_temp = [];
ymask_temp = [];
junk = [];
for i=1
A=imread(['Image0001.bmp']);
[junk,xmask_temp,ymask_temp]=roipoly(A);
a = 1+size(xmask_temp,1);
xmask(1:size(xmask_temp,1),i)=xmask_temp;
ymask(1:size(ymask_temp,1),i)=ymask_temp;
[junk,xmask_temp,ymask_temp]=roipoly(A);
b = a-1+size(xmask_temp,1);
xmask(a:b,i)=xmask_temp;
ymask(a:b,i)=ymask_temp;
b = b+1;
[junk,xmask_temp,ymask_temp]=roipoly(A); % where the problem starts
c = b-1+size(xmask_temp,1);
xmask(b:c,i)=xmask_temp;
ymask(b:c,i)=ymask_temp;
end
B = roipoly(A,xmask,ymask);
imshow(B);
采纳的回答
Image Analyst
2018-8-17
In the loop, call poly2mask() to get a new mask for the new polygon they draw. Then OR it in with the image.
Before the loop
mask = false(rows, columns); % Initialize final mask
Then in the loop
thisMask = poly2mask(xVertices, yVertices, rows, columns);
mask = mask | thisMask; % Combine this mask with the final mask.
That way you build up the final mask by ORing in each individual mask one at a time. Change variable names to whatever you're using, of course.
2 个评论
Thomas Darwent
2018-8-20
Image Analyst
2018-8-20
Why do you say "but"? You still use roipoly(). You just also use poly2mask to create a mask from those vertices, and then OR in that mask with a cumulative mask you're building.
If you can't figure it out, attach 'Image0001.bmp' and I'll make a full demo.
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