Frequency Based

These commands perform Fourier and inverse Fourier transformations of images. By default, the transformations will automatically convert images between Fourier to natural orders as expected. For example, 2-D FFT will transform the points into natural order after the Fourier transform. Similarly the inverse, 2-D IFFT, will reorder the points from natural order to Fourier order before applying the inverse Fourier transformation.

As you would expect, images that undergo frequency filtering will be complex-valued after than filtering. Only the real component is shown by CTSim. However, CTSim does have options for converting a complex-valued image into a real-valued image via the Magnitude and Phase filtering commands.

The available frequency-based filtering commards are:

2-D FFT
2-D IFFT
FFT Rows
IFFT Rows
FFT Columns
IFFT Columns
2-D Fourier
2-D Inverse Fourier
Shuffle Fourier to Natural Order
Shuffle Natural to Fourier Order
Magnitude
Phase