2D DFT from 1D DFT
Building the Cantata Workspace
- Create a small white box 4 x 16 centered in a 128 square black
backgroung using the operators
Constant
and
Pad
. Display it.
- First take the DFT of the lines of the image, using the
FFT
operator selected to operate just in the width dimension.
Display it.
- Take the DFT of the columns of the previous DFT, using the
FFT
operator selected to operate just in the height dimension.
Display it.
- Compare this result with the one taking using the
FFT
operator selected to operate in both dimensions. Use operator
Compare Objects
.
Warning: There was a bug during the writing of this lesson concerned the
shifting of the DFT to the center of the image. To work properly now,
just select one of the DFTs to center the spectrum.
Exercises
- Perform the inverse DFT using the principle of the separable
transform.
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