Related to The Proper Way to Do Sinc Downsampling (DFT Downsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples, how can one apply Sinc downsampling in the DFT / FFT domain for a 2D signal?
What are considerations when implementing it in MATLAB?
This the downsampling case of in Applying 2D Sinc Interpolation for Upsampling in the Fourier Domain (DFT / FFT) as requested in comments.
As written in Applying 2D Sinc Interpolation for Upsampling in the Fourier Domain (DFT / FFT), when dealing with the Since Interpolation / DFT Interpolation in $ n > 1 $ dimensions one could use the separability property of the DFT.
Hence one could use the code from The Proper Way to Do Sinc Downsampling (DFT Downsampling) for Uniformly Sampled Discrete Signals with Finite Number of Samples as done in the upsampling case with the only difference being asking the output size to be smaller.
I updated the code in Applying 2D Sinc Interpolation for Upsampling in the Fourier Domain (DFT / FFT) to support this. It even supports the case we upsample in one dimension while downasampling in the other.
