Launch an algorithm in several samples extracted from an image

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Rdmato33
Rdmato33 2015-10-13
评论： Thorsten 2015-10-14
Hello, I would like to extract features of a raster image by using an active contour algorithm (see below). My goal is to obtain morphometry of each object. For each of them (92 features), I have created same size matrix (5 rows, 5 columns) with this code :
%svf is the name of the image
%xy_points are the center coordinates of each feature
For m=1:92;a(:,:,m)=svf(xy_points(m,1)-2:xy_points(m,1)+2,xy_points(m,2)-2:xy_points(m,2)+2);end
Thus, I obtained 92 matrix of 5x5.
This is my problem : I have succeeded in applying the active contour algorithm on 1 image (the whole image called "svf"). But I don't know how to apply it on my samples (matrix for each feature) and to repeat the process.
Thanks for your help.

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回答（1 个）

Thorsten
Thorsten 2015-10-13
Why not
for m=1:92;
result = activecontour(svf(xy_points(m,1)-2:xy_points(m,1)+2,xy_points(m,2)-2:xy_points(m,2)+2));
% do something with result
end
  2 个评论
Rdmato33
Rdmato33 2015-10-13
编辑：Rdmato33 2015-10-13
Thanks for you answer. Actually, I use a different algorithm than "activecontour". As you can see below, the code is more complex. Do I have to insert your code at the beginning of the algorithm (at the step of resizing)?
imwrite(svf,'../images/svf.pgm');
[I,map] = rawread('../images/svf.pgm');
I=imresize(I,1);
disp(' Compute edge map ...');
f = 1 - I/255;
f0 = gaussianBlur(f,1);
[px,py] = gradient(f0);
figure(1);
subplot(121); imdisp(-f); title('snake potential');
subplot(122); quiver(px,py);
axis('image', 'ij', 'off');
title('traditional force');
disp(' ');
disp(' Press any key to start the deformation');
pause;
figure(1); subplot(121);
colormap(gray(64));
image(((1-f)+1)*40); axis('square', 'off');
figure, imshow(I,map);
colormap(gray(64));
t = 0:0.5:1;
x = 120
y = 20
[x,y] = snakeinterp(x,y,2,0.5);
snakedisp(x,y,'r')
pause(1);
for i=1:20,
[x,y] = snakedeform2(x,y,0.05,0,1, 2, 0.15,px,py,5);
[x,y] = snakeinterp(x,y,2,0.5);
snakedisp(x,y,'r')
title(['Deformation in progress, iter = ' num2str(i*5)])
pause(0.1);
end
disp(' ');
disp(' Press any key to display the final result');
pause;
figure(1); subplot(121);
colormap(gray(64));
image(((1-f)+1)*40); axis('square', 'off');
snakedisp(x,y,'r');
title(['Final result, iter = ' num2str(i*5)]);
Thorsten
Thorsten 2015-10-14
Your code has various issues:
. if you have swf as your image, why do you write it to a pgm image, then read it, instead on just working with swf
. why to you scale with 1, i.e., no scaling?
Besides this, my suggestion was to write a function activecontour with the image as an argument, that you then call in a loop over all your subimages.

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