<a href="/keyword/discrete-cosine-transform/" ><a href="/keyword/discrete-cosine/" >discrete cosine</a> transform</a> Nuno Vasconcelos UCSD Discrete Fourier Transform last classes, we have studied the DFT due to its computational efficiency the DFT is very popular however, it has strong disadvantages for some applications it is complex it has poor energy compaction energy compaction is the ability to pack the energy of the spatial sequence into as few frequency coefficients as p q y possible this is very important for image compression we represent the signal in the frequency domain if compaction is high we only have to transmit a few coefficients high, instead of the whole set of pixels 2 <a href="/keyword/discrete-cosine-transform/" ><a href="/keyword/discrete-cosine/" >discrete cosine</a> transform</a> a much better transform, from this point of view, is the DCT in this example we see the amplitude spectra of the image above under the DFT and DCT note the much more concentrated histogram obtained with the DCT why is energy compaction important? the main reason...
DCT