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Topic: sub-pixel shifting of a matrix
Replies: 14   Last Post: Feb 7, 2013 12:23 PM

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Rajesh

Posts: 26
Registered: 2/22/10
Re: sub-pixel shifting of a matrix
Posted: Feb 26, 2010 5:24 AM
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> You can extrapolate with zeros or any other desired value using the EXTRAPVAL option.
>


I already tried that but the background in the image has a certain mean and sd as would be the case for an image. moreover replacing it with a certain constant requires a knowledge of the actual pixl value of the background which will have to be obtained from the image itself by picking a certain area or certain pixel of the background in the image but that, i guess, would take further time (or no?) since i am handling mutliple images in a loop while translatng them.

Also, replacing them with a constant might give artefacts in futue reconstructions (rings in CT images)
>
> Result=zeros(size(Image));
> Result(1:end+1-k,1:end+1-j)=Image(k:end,j:end);


Thanks for this as well.

> If the object is completely surrounded by background values of zero, I don't see what's challenging about that. What I've outlined above will work.

thanks (appologies if this amounts to hijacking the original thrd)



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