how can i calculate area enclosed by contour?

Question

dziri halima 2015-7-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/229502-how-can-i-calculate-area-enclosed-by-contour

评论： Image Analyst 2015-7-15

采纳的回答： Image Analyst

I used snake to enclosed the left ventricle; how can i calculate area enclosed by contour?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2015-7-11

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/229502-how-can-i-calculate-area-enclosed-by-contour#answer_185765

在 MATLAB Online 中打开

If you used activecontour, it returns a binary image, so you simply label it and call regionprops:

labeledImage = bwlabel(binaryImage);
measurements = regionprops(labeledImage, 'Area');
allAreas = [measurements.Area];

7 个评论
显示 5更早的评论隐藏 5更早的评论

dziri halima 2015-7-11

编辑：Walter Roberson 2015-7-12

在 MATLAB Online 中打开

thinks sir; these some image and this the code

clc;  clear all;close all;
   % Read in the cardiac image
  b = imread('c:/image/e1.jpg');
    b=b(:,:,1);
    a=fspecial('average',[5 5]);
    G=imfilter(b,a);
    [row,col]=size(G);
    G=G(:,:,1);
    I=double(G);
    figure(1);
    imdisp(I);
    title('Original image');
   % Compute its edge map
     I0 = gaussianBlur(I,1);
     II=1-I0/255;  %
     [u1,v1] = gradient(II); %---------- Compute its edge map
     f =sqrt(u1.^2+v1.^2); 
     figure(2)
     imdisp(f);
     title('Step Edge map');
   % Compute the GVF of the edge map f
   %      disp('display AGVF force field')  
   %    [u,v] = MyADF(f, weights,iter,sigma,deltat,fil,show)
        [u,v] = MyADF(f,[0 0.05],50,0.5,0.5,'null','ns');
        mag = sqrt(u.*u+v.*v);
         px = u./(mag+1e-10); py = v./(mag+1e-10); 
           % display the GVF 
           figure(3);
      imdisp(I);
            hold on
           quiver(px,py,'r','LineWidth',1);
            title('Adaptive GVF field');
  hold off
% initialization of snake
  figure(4);
  imdisp(I);
    x =35+5*cos(0:0.1:2*pi);
    y =35+5*sin(0:0.1:2*pi);
    [x,y] = snakeinterp(x,y,1,0.2);
  hold on, plot([x;x(1,1)],[y;y(1,1)],'r--','LineWidth',1);
 hold off
  pause(1);      
%%snake parameters
ITER=5;
alpha=0.1;
beta=0.1;
gamma=1;
kappa=0.1;
%%snake deformation
 figure(5),
imdisp(I); 
hold on, plot([x;x(1,1)],[y;y(1,1)],'r--','LineWidth',1)
    for i=1:ITER
        [x,y] = snakedeform(x,y,alpha,beta,gamma,kappa,px,py,5);
        [x,y] = snakeinterp(x,y,1,0.5);
       hold on
       x = x(:); y = y(:);
       plot([x;x(1,1)],[y;y(1,1)],'r','LineWidth',1);
        hold off   
        title(['Deformation in progress,  iter = ' num2str(i*5)]);
        pause(0.5);
      end  
         hold on, plot([x;x(1,1)],[y;y(1,1)],'LineWidth',1,'Color','r');
%%save the ultimate result     
    figure(6),
    imdisp(I),
    title('Result');
    hold on, plot([x;x(1,1)],[y;y(1,1)],'LineWidth',1,'Color','b');
 nb = im2bw(I, graythresh(I));
    labeledImage = bwlabel(nb);
 measurements = regionprops(labeledImage, 'Area');
allAreas = [measurements.Area]

dziri halima 2015-7-14

hello sir; i do not find a soulution to my problem.

Image Analyst 2015-7-15

在 MATLAB Online 中打开

You're just calling some automatic threshold on the image and using that to calculate the area.

nb = im2bw(I, graythresh(I));
labeledImage = bwlabel(nb);
measurements = regionprops(labeledImage, 'Area');
allAreas = [measurements.Area]

You're not even using the results of your snakes algorithm at all! Even so, I'd be surprised if the auth-thresholded image for both images gave the very same areas. But regardless, I don't think that's what you want to do. You can use the snake boundaries and pass them into poly2mask() to create a binary image from the snake boundaries.

请先登录，再进行评论。