How to create multiple ROI in the same figure? I'd like to manually draw multiple region on an image to create a mask of the drawn regions. I attached the code to do it using ellipse that does the job for 5 region, but only last region is displayed.

I = imread('13170.jpg');
im = imshow(I);
e = imellipse(gca);% now pick ROI
BW = createMask(e,im);% get BW mask for that ROI
BW(:,:,2) = BW;
BW(:,:,3) = BW(:,:,1);
ROI = I;
ROI(BW == 0) = 255;
figure, imshow(ROI,'Border','tight');

Answer 1

[KSSV]

You put a loop and call the code the number of times you want. Just call it multiple times and save all the regions.

Refer this file exchange, may be useful: https://in.mathworks.com/matlabcentral/fileexchange/31388-multi-roi-mask-editor-class

[Mei Synn Tan]

Hi...Thanks for replying my question. Like this? now I can draw multiple ellipse, but I dunno how to save all region.

I = imread('13170.jpg');
im = imshow(I);
e = imellipse(gca);% now pick ROI
position = wait(e);
BW = createMask(e,im);% get BW mask for that ROI
while sum(BW(:)) >= 5
BW(:,:,2) = BW;
BW(:,:,3) = BW(:,:,1);
ROI = I;
ROI(BW == 0) = 255;

e = imellipse(gca);
setColor(e, 'red');
position = wait(e);
BW = createMask(e,im);
end
figure, imshow(ROI,'Border','tight');

[KSSV]

clc; clear all ;
N = 5 ;
I = imread('junk.jpg');
for i = 1:N
    im = imshow(I);
    e = imellipse(gca);% now pick ROI
    BW = createMask(e,im);% get BW mask for that ROI
    BW(:,:,2) = BW;
    BW(:,:,3) = BW(:,:,1);
    ROI = I;
    ROI(BW == 0) = 255;
    figure(i)
    imshow(ROI,'Border','tight');
end

[Mei Synn Tan]

Thank for helping me, but I am still cannot save all the regions. How to do for each region save to array, for each array draw it out, then for each object in array draw it out. Thanks

N = 5 ;
I = imread('13170.jpg');
im = imshow(I);
for i = 1:N
e = imellipse(gca);% now pick ROI
setColor(e, 'red');
position = wait(e);
    BW = createMask(e,im);% get BW mask for that ROI
    BW(:,:,2) = BW;
    BW(:,:,3) = BW(:,:,1);
    ROI = I;
    ROI(BW == 0) = 255;
end
figure(i)
imshow(ROI,'Border','tight');

[KSSV]

clc; clear all;
N = 5 ;
I = imread('junk.jpg');

iwant = cell(N,1) ;
for i = 1:N
    im = imshow(I);
    e = imellipse(gca);% now pick ROI
    setColor(e, 'red');
    % position = wait(e);
    BW = createMask(e,im);% get BW mask for that ROI
    BW(:,:,2) = BW;
    BW(:,:,3) = BW(:,:,1);
    ROI = I;
    ROI(BW == 0) = 255;
    iwant{i} = ROI ;
end
for i = 1:N
    figure
    imshow(iwant{i},'Border','tight');
end

[Meera chandran]

Any Idea on how to draw multiple ROI's in 2 images which are place in 'montage' mode and obtain their feature points?

I am getting only one ROI point safter drawing it