A question about Direct Fourier Reconstruction,or say the central silce theorem

Hello everyone ,I have a question that pazzled me about a long time,I wonder if someone will help me

The websites https://code.google.com/p/centralslice/downloads/list have the matlab code about central slice theorem.I want find the author to ask ,but don't find them .

question one :I don't understand why do a ifftshift to the projection before interplotion? question two :If the oversampling_ratio greater than one ,the reconstuction image will in the center,Why ? I think the frequency density is high ,the reconstruction image will in the top left corner.

Answer 1

[Tiago Ramos]

in order for you to check ifftshift and fftshift issues I suggest: https://se.mathworks.com/matlabcentral/fileexchange/25473-why-use-fftshift-fft-fftshift-x----in-matlab-instead-of-fft-x--

Interpolation in the fourier domain corresponds to zero-padding in the direct domain. Oversampling an fft is the same as performing a sinc interpolation (The correct one) in the fourier domain

Best Tiago