Save plotted lines in an matrix

Question

Bruno Neto 2022-6-14

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1740310-save-plotted-lines-in-an-matrix

评论： Kevin Holly 2022-6-22

Here's my code to obtain these two lines:

[B,L,N,A] = bwboundaries(ImgClosed); 
figure
imshow(ImgClosed)
hold on; 
% Loop through object boundaries  
for k = 1:N 
    % Boundary k is the parent of a hole if the k-th column of the adjacency matrix A contains a non-zero element 
    if (nnz(A(:,k)) > 0) 
        boundary = B{k}; 
        plot(boundary(:,2),boundary(:,1),'r','LineWidth',2); 
        % Loop through the children of boundary k 
        for l = find(A(:,k))' 
            boundary = B{l}; 
            plot(boundary(:,2),boundary(:,1),'g','LineWidth',2); 
        end 
    end 
end

As ImgClosed is the binary image of the object I'm analysing.

And this is the result:

I want to save both lines (red and green) in an unique matrix so i can plot them again on top of another image. How can i save them?

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Answer 1

Kevin Holly 2022-6-14

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1740310-save-plotted-lines-in-an-matrix#answer_985655

在 MATLAB Online 中打开

You can save the plot and extract the XData and YData from it's subfields as shown below.

[B,L,N,A] = bwboundaries(ImgClosed); 
figure
imshow(ImgClosed)
hold on; 
% Loop through object boundaries  
for k = 1:N 
    % Boundary k is the parent of a hole if the k-th column of the adjacency matrix A contains a non-zero element 
    if (nnz(A(:,k)) > 0) 
        boundary = B{k}; 
        redline = plot(boundary(:,2),boundary(:,1),'r','LineWidth',2); 
        % Loop through the children of boundary k 
        for l = find(A(:,k))' 
            boundary = B{l}; 
            greenline = plot(boundary(:,2),boundary(:,1),'g','LineWidth',2); 
        end 
    end 
end
figure
axes
plot(redline.XData,redline.YData,'r','LineWidth',2)
hold on
plot(greenline.XData,greenline.YData,'g','LineWidth',2); 

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Kevin Holly 2022-6-15

在 MATLAB Online 中打开

test.png

ImgClosed = imread('test.png');

ImgClosed=im2bw(ImgClosed);

[B,L,N,A] = bwboundaries(ImgClosed);

figure

imshow(ImgClosed)

hold on;

for k = 1:N

% Boundary k is the parent of a hole if the k-th column of the adjacency matrix A contains a non-zero element

if (nnz(A(:,k)) > 0)

boundary = B{k};

redline = plot(boundary(:,2),boundary(:,1),'r','LineWidth',2);

% Loop through the children of boundary k

for l = find(A(:,k))'

boundary = B{l};

greenline(l,:) = plot(boundary(:,2),boundary(:,1),'g','LineWidth',2);

end

figure

axes

plot(redline.XData,redline.YData,'r','LineWidth',2)

hold on

x=redline.XData;

y=redline.YData;

c = [(1:length(x)-1).' (2:length(x)).'];

for jj = 1:size(greenline,1)

try

plot(greenline(jj).XData,greenline(jj).YData,'g','LineWidth',2);

x_start = length(x);

x=[x greenline(jj).XData];

y=[y greenline(jj).YData];

c = [c;(x_start+(1:length(greenline(jj).XData)-1)).' (x_start+(2:length(greenline(jj).XData))).'];

catch

end

DT = delaunayTriangulation(x',y',c);

Warning: Duplicate data points have been detected and removed.
The Triangulation indices and constraints are defined with respect to the unique set of points in delaunayTriangulation.

% IC = incenter(DT);

triplot(DT)

figure

DT = delaunayTriangulation(x',y',c);

Warning: Duplicate data points have been detected and removed.
The Triangulation indices and constraints are defined with respect to the unique set of points in delaunayTriangulation.

IO = isInterior(DT);

triplot(DT(IO, :),DT.Points(:,1), DT.Points(:,2),'LineWidth', 2)

Bruno Neto 2022-6-17

Thank you so much! Is there anyway I can densify the triangles inside the object? So I can get something like the delaunay triangulation I showed above?

Kevin Holly 2022-6-22