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Asked by AP
on 11 Feb 2013

Dear All,

I have a 4D array V, with the size [144 144 12 25]. In fact, it is a 4D medical image with 12 stacked slices in 25 different time. I want to apply a mask, named M, to each image in the array in a vectorized way. M is a 144x144 array containing logical values. Could someone help me how to do it?

Thanks,

Ahmad

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Answer by José-Luis
on 11 Feb 2013

Edited by José-Luis
on 12 Feb 2013

Accepted answer

data = rand(144,144,12,25); your_mask = rand(144,144) > 0.5;

Assuming you want to multiply by the mask:

your_result = bsxfun(@times,data,mask);

Note that you can do operations other than multiplication. Please have a look at

doc bsxfun

Show 1 older comment

AP
on 11 Feb 2013

I want the operation on each image. I thought bsxfun is only for each pixel and can't be applied to each image in a 4D array. Please correct me if I am wrong: so when we call bsxfun(@times,data,mask), bsxfun applies the mask to each 144x144. Is that right?

Answer by Conrad
on 11 Feb 2013

Something like this:

fV = V.*M(:,:,ones(1,size(V,3)),ones(1,size(V,4)));

Conrad

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## José-Luis

Direct link to this comment:http://www.mathworks.com/matlabcentral/answers/63002#comment_128651

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