The Discrete Cosine Transform (DCT
) is a method of reformating data which helps separate an image
sub-bands of differing importance. The DCT is similar to the Discrete Fourier Transform
) in that it transforms a signal or image from the spatial domain
to the frequency domain
. However, the DCT does a better job of concentrating energy into lower order coefficients
This is one part in several steps to generating a JPEG or MPEG compressed file.