get pixel index from region props

If someone help or try help to me ,I'll be so thankful : as shown in the image , I used 'regionprops' function to divide it into five regions. I want to copy any region (say the second region)from this image and put in a new image which has the same size as original image ,how can I get the pixel indices of that region . thank you.

[Benjamin Drewry]

this is how I do it, but there are probably better ways. I.e. to separate out the 'jacket' region of the matlab provided pout image

img=imread('pout.tif');

mask=img>130;

bwlabel(mask);

figure(); imagesc(ans);

stats=regionprops(mask, 'all');

bkdg=zeros(img);

y=stats(25).PixelList(:,2);

x=stats(25).PixelList(:,1);

for i=1:length(I)

bkdg(y(i),x(i))=1;

end

figure(); imagesc(bkdg);

final=double(img).*bkdg;

figure(); imagesc(final);

[Image Analyst]

Benjamin, please fix the code (so it at least runs), and put it down in the official "Answers" section, not up here in the comments section where we ask posters for additional clarification.

Answer 1

[Image Analyst]

You can do that, but it's not the most efficient way, so I won't go into it (besides, it's more complicated). The way you want to do it is with ismember(). You use your labeled image and create the 5 new images with ismember

[labeledImage, numRegions] = bwlabel(binaryImage);
binaryRegion1 = ismember(labeledImage, 1) > 0;
binaryRegion2 = ismember(labeledImage, 2) > 0;
binaryRegion3 = ismember(labeledImage, 3) > 0;
binaryRegion4 = ismember(labeledImage, 4) > 0;
binaryRegion5 = ismember(labeledImage, 5) > 0;

[Walter Roberson]

ismember() returns true/false for its first output so the > 0 is redundant .

[Image Analyst]

majed's "Answer" moved here:

thanks a lot , your technique works good . but how can i remove any region from the original image and put in zeros image(with the same size as original one) in the same position(indices) as the original one.

[Image Analyst]

Do this

grayImage(binaryImage1) = 0;