# Save object's boundary as coordinate arrays.

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yaswanth pushpak on 26 May 2017
Commented: yaswanth pushpak on 28 May 2017
I have traced an image boundary and I need to save it as coordinate arrays. Actually I'm working on thermal image where I first extracted only the red component of the RGB image and then to black and white image then I have done morphological closing on it and obtained object's boundary.Actually I'm confused abt how to get boundary then I found it here and I have to save it in coordinate arrays.Thanks for your help in advance. My code looks like this
a = imread('D:\New folder (5)\New folder (5)\VID-20170522-WA0021 (5-23-2017 3-45-10 PM)\yash.jpg');
a_red=a;
a_green=a;
a_blue=a;
a_red(:,:,2)=0;
a_red(:,:,3)=0;
BW = im2bw(a_red, 0.2);
se=strel('disk',10);
closeBW=imclose(BW,se);
[B,L] = bwboundaries(closeBW,'noholes');
c=label2rgb(L, @jet, [.5 .5 .5]);
imshow(c);
hold on
for k = 1:length(B)
boundary = B{k};
plot(boundary(:,2), boundary(:,1), 'w', 'LineWidth', 2)
end

MathReallyWorks on 26 May 2017
yaswanth pushpak on 28 May 2017
yaswanth pushpak on 28 May 2017
I've attached the thermal image and I need to detect the face.Thanks for ur help in advance.

MathReallyWorks on 26 May 2017
Hello yaswanth,
As you have not shared how you have traced object boundary, it is a bit difficult to answer you question efficiently.
Anyways, I can tell you a simple approach to do this task.
Convert your image to grayscale and pass it to a high pass filter. This will remove all points except the boundary of object.
Then use
C=corner(I); %I is modified image
It will store all the corner points in an array C.

#### 1 Comment

yaswanth pushpak on 26 May 2017
Actually I'm working on thermal image where I first extracted only the red component of the RGB image and then to black and white image then I have done morphological closing on it and obtained object's boundary.Actually I'm confused abt how to get boundary then I found it here and I have to save it in coordinate arrays.Thanks for your help in advance