  Many powerful imaging techniques for cold atoms are based on determining the
optical density by comparing a beam image having passed through the atom cloud
to a reference image taken under similar conditions with no atoms. In practice
the beam profile typically contains interference fringes whose phase is not
stable between camera exposures. To reduce the error of these fringes in the
computed optical density, an algorithm based on principle component analysis
(PCA) is often employed. However, PCA is general purpose and not tailored to
the specific case of interference fringes. Here we demonstrate an algorithm
that takes advantage of the Fourier-space structure of interference fringes to
further reduce the residual fringe signatures in the optical density.
