Supprimer un cylindre d un volume

Version imprimable

After tackling the things above, you have to remove the U shaped object from the image.
You don't have to use imfill necessarily; you can come up with anything. I can recommend
another way to solve it. For example if you create a cylinder which has values 1 inside
and 0 outside; and place it so that it contains only the VOI (volume of interest) we are
interested and excludes the U shaped object; then you can multiply it with data which
will solve the problem. You can implement it as follows:

Toujours pour le même projet,
Je dois supprimer de mon volume une forme en U

J ai pense a utiliser un volume cylindrique qui contiendrait le volume d interet (valeur 1 a l interieur et 0 a l exterieur) et que je multiplierai avec par une bonne donnee pour supprimer ce U
mais je bloque pour identifier X_DIM, Y_DIM, Z_DIM, RADIUS et leurs centres.

Merci d avance
Code:

1 2 3 4 5 6 [X Y Z] = meshgrid(1:<X_DIM>, 1:<Y_DIM>, 1:<Z_DIM>); cylinder_mask = (X - <CENTER_ON_X_DIMENSION>).^2+(Y - CENTER_ON_Y_DIMENSION).^2 < <RADIUS>2; % Then finally you multiply it with the image; new_volume = uniform_volume.*cylinder_mask;

Code:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
clear, close all
 
d = dir('*.dcm');
 
volume_data = zeros(256, 256, 224);
 
slice_thickness = zeros(1,224);
 
for i=1:numel(d)
file_name = strcat('IM',num2str(i),'.dcm');
dicom_info = dicominfo(file_name);
anatomical_location_of_dicom_image = dicom_info.InstanceNumber;
dicom_image = dicomread(file_name);
 
dicom_image_resized = imresize(dicom_image, [256 256]);
 
slice_thickness(anatomical_location_of_dicom_image) = dicom_info.SliceThickness;
 
volume_data(:,:,anatomical_location_of_dicom_image) = dicom_image_resized;
end
 
high_res_volume = volume_data(:,:,1:75); 
low_res_volume = volume_data(:,:,76:224);
 
[X, Y, Z] = meshgrid(1:256, 1:256, linspace(1,75,56));
 
resized_volume_data = interp3(high_res_volume,X,Y,Z);
 
uniform_volume = cat(3, resized_volume_data, low_res_volume);
 
[X, Y, Z] = meshgrid(1:256, 1:256, 1:224);
cylinder_mask = (X - 128).^2+(Y - 128).^2 < 90.^2 ;
 
% The line above creates a cyclinder in which  the interior region is 1 and the rest is 0
 
%-------------HINT----------------------
% And here you have to make a ELEMENT BY ELEMENT multiplication; however what you try below is a MATRIX multiplication
% that is why it doesn't work
 
new_volume = uniform_volume.*cylinder_mask;
 
 
smooth_new_volume = smooth3(new_volume);

Voila mon code qui normalement devrait etre bon mais apparement il y a une erreur de dimension que je n arrive pas a trouver...

Code:

1
2
3
4
5
6
 
??? Error using ==> times
Array dimensions must match for binary array op.
 
Error in ==> task3edward at 97
new_volume = uniform_volume.*cylinder_mask;

Si quelqu un voit l erreur :p

merci d avance

02/05/2009, 13h48
Djang0

erreur de memoire
juste clean all et relancer matlab a suffit