Image processing fun with FFT! (iii)

Finally a scanned image of a persons face containing an artifact of the paper that the photo was printed on. These are not uncommon when scanning old photographs.


Image pre-restoration

Enter the FFT. The images below show the power spectrum of the image above before and after the frequency components responsible for the periodic noise have been filtered.


FFT power spectrum and filtered power spectrum

Now taking the inverse of the FFT results in an image with most of the periodic noise suppressed.


Image post-restoration




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