I have an image and if I then plot the boundary of just the left and edges with the code below:
imshow(I); hold on; [B,L,N] = bwboundaries(I);
for k=1:length(B),
boundary = B{k};
BL=size(boundary);
plot(boundary(1,2), boundary(1,1), '*g','MarkerSize',15);
for j=1:10:BL(1)
plot(boundary(j,2), boundary(j,1), '.r','MarkerSize',5);
end
end
I get this image
The starting point (the green star) for the left edge is at the left side of the image, which is what I expected. However, the starting point for the right edge is towards the middle
Apparently this is because `bwboundaries` deals with tracing objects in clockwise direction, whereas the 2nd edge needs to be traced counterclockwise for it to begin and end on the right boundary of the image
I was hoping the start and end points for both edges would be where the blue dots are
I also was hoping the boundary array for the right edge from `bwboundaries` would be sorted from the corrected startpoint to endpoint (like how it is for the left edge), so that for edges that don't touch the border, I can then draw a straight line connecting them (like in red in the last image), and then use `polyshape` and `area` on it, so I can find the area of that closed region, like in the image belo
how can I do this in Matlab?
