CODEWITHSUNDEEP
signal-processingfft
user1459175
user1459175

Reputation: 313

zero padding fft

I have an image of size 786*786 and I would like to zero pad it to make it 1024*1024 so I that I can use my radix 2 algorithm. In the input side I would basically add zeros at the end so that the length would be 1024*1024 and my fft would produce a 1024*1024 output, my question is how do I retrieve the correct 786*786 output?

Thank you for answering.

Upvotes: 1

Views: 3198

Answers (1)

Paul R
Paul R

Reputation: 212929

The output of the FFT is still correct, even though you zero padded the input. The difference is that the output has been interpolated in the frequency domain, so you have more apparent resolution (although of course no more information has been magically gained - you are just seeing additional points due to the interpolation). If you do an inverse FFT you will get back to your original zero padded input.

Upvotes: 4

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