Drawing two shapes on one image

This is part of what I have done for drawing a shape on my images:

    ...
    ...
    k = convhull(x,y);
    I=imread('img.png');
    imshow(I)
    hold on
    plot(x(k),y(k),'r-',x,y,'b+');
    BW = roipoly(I, x(k), y(k) );

What should I do in order to receive the binary result as in BW, but that contains the other shape (i.e; xx, yy)?

I kept hold on, and was able to plot the second shape, but the issue was how to get the binary result of the two shapes at the image.

Thanks.

Answer 1

[Youssef Khmou]

You can transform I into logical matrix first ( binary), then perform the other operations to add the shape after executing the command 'hold on', , here is an example :

I=imread('circuit.tif');
B=im2bw(I);
% example of drawing shape in the binary image B
% first shape.
p1=150+rand(100,1)*200;
p2=100+rand(100,1)*100;

 % second shape.
 p3=10+rand(100,1)*50;
 p4=10+rand(100,1)*60;

 k=convhull(p1,p2);
 k2=convhull(p3,p4);

 imshow(B), hold on, plot(p1(k),p2(k),'-r',p3(k2),p4(k2),'-g'), hold off;

[med-sweng]

@Youssef KHMOU. Thanks for you reply. The issue is in adding another shape. If I add another shape, I want to see it alongside with the first shape. How can this be performed?

[Youssef Khmou]

you can try the edited code above, it it working fine, i hope you will explain better your situation it the edited code is not working .

Answer 2

[Image Analyst]

Try this:

% Read in first shape and display it.
I=imread('img.png');  % I'm assuming it's binary.  Make it binary if not.
imshow(I)
[rows, columns, numberOfColorChannels] = size(I);
hold on

% Now add second shape, assuming we have just a list of x,y coordinates.
% First make it a binary image.
secondBinaryImage = poly2mask(x, y, rows, columns);
% Get the convex hull of it
secondBinaryImage = bwconvhull(secondBinaryImage);
% Then OR it in with the first binary image.
outputBinaryImage = I | secondBinaryImage; % OR operation.
imshow(outputBinaryImage); % Display result.