• The image of a cat

  

• The spectra of the image (DFT, DCT, and WHT)

  

• The low-pass filtered images (DFT and DCT). Note the ringing effect caused by the ideal filter.

  

• The low-pass filtered images (DFT, DCT, and WHT). The ringing effect no longer exists due to the Butterworth filter.

  

• The high-pass filtered images (DFT, DCT, and WHT).