如何繪製分支點和終點之間的中點

Question

這是我的圖像我已經找出了終點和分支點，但是我想繪製這兩點之間的一個點，因爲我會幫助我在點。請給我一些代碼來找到兩點之間的中點或質心。

clc; 
clear all; 
% read in a sample image -- also see letters.png, bagel.png 
J=imread('ds2.jpg'); 

% Normalize and Binarization 
b = imresize(J,[100,100]); 
th = graythresh(b); 
BW1 = im2bw(b, th); 
figure; 
imshowpair(b, BW1, 'montage'); 

% the standard skeletonization: 

skelimg = bwmorph(~BW1,'thin',inf); 

mn = bwmorph(skelimg,'branchpoints'); 
[row, column] = find(mn); 
branchpts = [row column]; 


Endimg = bwmorph(skelimg,'endpoints'); 
[row,column] = find(Endimg); 
Endpts = [row column]; 

figure;imshow(skelimg); 

hold on; 

plot(branchpts(:,2),branchpts(:,1),'g*'); 
plot(Endpts(:,2),Endpts(:,1),'g*'); 
hold on; 

reference image

Answer 1

bwdistgeodesic（helpful link）可以幫你。你可以做這樣的事情：

clc; 
clear all; 
% read in a sample image -- also see letters.png, bagel.png 
J=im2double(imread('circles.png')); 

% Normalize and Binarization 
b = imresize(J,[100,100]); 
th = graythresh(b); 
BW1 = im2bw(b, th); 
figure; 
imshowpair(b, BW1, 'montage'); 

% the standard skeletonization: 
skelimg = bwmorph(BW1,'thin',inf); 

mn = bwmorph(skelimg,'branchpoints'); 
[row, column] = find(mn); 
branchpts = [row column]; 


Endimg = bwmorph(skelimg,'endpoints'); 
[row,column] = find(Endimg); 
Endpts = [row column]; 

n = size(Endpts,1); 
Cntrpts = zeros(n,2); 
for ii = 1:n 
    % compute end & branch points geodesic distance transform 
    dEnd = bwdistgeodesic(skelimg, Endpts(ii,2), Endpts(ii,1), 'quasi-euclidean'); 
    [~,closestBranchIdx] = min(dEnd(mn)); 
    dStart = bwdistgeodesic(skelimg, branchpts(closestBranchIdx,2), branchpts(closestBranchIdx,1), 'quasi-euclidean'); 
    D = dStart + dEnd; 
    D = round(D * 8)/8; 
    D(isnan(D)) = inf; 
    paths = imregionalmin(D); 
    % compute geodesic distance on found path from end point and divide max distance by 2 for center point 
    dCenter = bwdistgeodesic(paths, Endpts(ii,2), Endpts(ii,1), 'quasi-euclidean'); 
    dCenter(isinf(dCenter)) = nan; 
    c = nanmax(dCenter(:))/2; 
    [~,idx] = nanmin(abs(dCenter(:) - c)); 
    [yc,xc] = ind2sub(size(dCenter),idx); 
    Cntrpts(ii,:) = [yc,xc]; 
end 

figure;imshow(skelimg); 
hold on; 
plot(Cntrpts(:,2),Cntrpts(:,1),'ro') 

plot(branchpts(:,2),branchpts(:,1),'g.'); 
plot(Endpts(:,2),Endpts(:,1),'b.'); 
hold on; 
disp(B) 

編輯 - 所有與中心檢測點：

Allpts = [Endpts;branchpts]; % all possible points 
n = size(Allpts,1); 
Cntrpts = nan(n^2,2); 
for ii = 1:n 
    for jj = [1:(ii-1) (ii+1):n]    
     % distance from start & end points 
     dEnd = bwdistgeodesic(skelimg, Allpts(ii,2), Allpts(ii,1), 'quasi-euclidean'); 
     dStart = bwdistgeodesic(skelimg, Allpts(jj,2), Allpts(jj,1), 'quasi-euclidean'); 
     D = dStart + dEnd; 
     D = round(D * 8)/8; 
     D(isnan(D)) = inf; 
     if all(isinf(D)) % seed points not connected 
      Cntrpts(ii,:) = [nan nan]; 
     end 
     % distance of center point (just half the distance) 
     paths = imregionalmin(D); 
     dCenter = bwdistgeodesic(paths, Allpts(ii,2), Allpts(ii,1), 'quasi-euclidean'); 
     dCenter(isinf(dCenter)) = nan; 
     c = nanmax(dCenter(:))/2; 
     [~,idx] = nanmin(abs(dCenter(:) - c)); 
     [yc,xc] = ind2sub(size(dCenter),idx); 
     Cntrpts((ii-1)*n + jj,:) = [yc,xc]; 
    end 
end 
figure;imshow(skelimg); 
hold on; 
plot(Cntrpts(:,2),Cntrpts(:,1),'r.') 
plot(branchpts(:,2),branchpts(:,1),'g.'); 
plot(Endpts(:,2),Endpts(:,1),'b.');