I was able to increase the density using the subtri() function upload by Kevin Moerman to the File Exchange.
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
end
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
end
DT = delaunayTriangulation(x',y',c);
triplot(DT)
figure
DT = delaunayTriangulation(x',y',c);
IO = isInterior(DT);
triplot(DT(IO, :),DT.Points(:,1), DT.Points(:,2),'LineWidth', 2)
h=trimesh(DT(IO, :),DT.Points(:,1), DT.Points(:,2),zeros(size(DT.Points(:,2))),'LineWidth', 2);
[Fs,Vs]=subtri(h.Faces,h.Vertices,2);% Note, you can increase the density by increase the value of the last input
figure
subplot(1,2,1);patch('Faces',h.Faces,'Vertices',h.Vertices,'FaceAlpha',0.5,'EdgeColor','k','LineWidth',2);
hold on;
subplot(1,2,2);patch('Faces',Fs,'Vertices',Vs,'FaceAlpha',0.5,'EdgeColor','k','LineWidth',2);
