# Isolate the outline of a shape.

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Alex Perrakis on 31 Aug 2021
Commented: Matt J on 31 Aug 2021
Hello i have through binarizing and using bwpropfilt i have got the attached image, my question is : does anyone have an idea how i can isolate the outline of the shape in the middle and have it as a shape?

Matt J on 31 Aug 2021
Edited: Matt J on 31 Aug 2021
Perhaps as follows?
BW=bwareafilt(Image,1);
BW=imerode(bwconvhull(BW),strel('disk',20))& ~BW;
BW=imopen(BW,ones(10,1));
BW=bwperim(bwareafilt(BW,1));
imshow(BW); zoom(3)
Alex Perrakis on 31 Aug 2021
Thanks i found a way with bwboundaries, now i have another problem.
%pic50=im2gray(pic050);
%pic1=im2gray(pic01);
newpicture=imsubtract(pic01,pic050);
%imshow(newpicture)
level = graythresh(newpicture);
level = 0.1405;
newbinpic = imbinarize(newpicture,level);
%imshowpair(newpicture,newbinpic,'montage')
newbinpic2=bwpropfilt(newbinpic,'perimeter',1);
imshowpair(newbinpic2,newpicture,'montage');
boundaries = bwboundaries(newbinpic2);
binaryImage = 0.6< newbinpic2 & newbinpic2<1;
hold on
for k=1:length(boundaries)
thisBoundary = boundaries{k};
x = thisBoundary(:,2);
y = thisBoundary(:,1);
plot(x,y,'r-','Linewidth',2);
end
I wanna somehow save the x and y coordinates and plot em in a normal plot, because this plots it on the image i linked before.
Matt J on 31 Aug 2021
Thanks i found a way with bwboundaries, now i have another problem.
If so, you should post it as a new question.

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