pb.add(DFTDescriptor.SCALING_UNITARY);
pb.add(DFTDescriptor.COMPLEX_TO_REAL);
corr = (PlanarImage) JAI.create("idft", pb);
// rearrange wrapped around image
pb.removeSources();
pb.removeParameters();
pb.addSource(corr);
pb.add(corr.getWidth() / 2);
pb.add(corr.getHeight() / 2);
corr = (PlanarImage) JAI.create("periodicshift", pb);
// crop interrogation area in case of zero padding