Howtosignalprocessing
What is fast DCT?
The discrete cosine transform (DCT) is the most popularly used signal processing tool for compressing images and sounds, found in standards such as JPEG and MP3. (Less often used methods include wavelet transforms, polyphase filters, Hadamard transforms, etc.)
Is DCT an algorithm?
In a DCT algorithm, an image (or frame in an image sequence) is divided into square blocks which are processed independently from each other, then the DCT of these blocks is taken, and the resulting DCT coefficients are quantized. This process can cause blocking artifacts, primarily at high data compression ratios.
Which is better DCT or DFT?
This is why DCTs...generally perform better for signal compression than DFTs and DSTs. In practice, a type-II DCT is usually preferred for such applications, in part for reasons of computational convenience. Additionally, you may find that this answer is useful too (from math.stackexchange.com).
Is DCT The real part of DFT?
DCT is NOT the real part of the DFT rather it is related to the DFT of a symmetrically extended signal/image. The energy of signal/image is packed mostly in only a few DCT coefficients (i.e. only a few significant X(k)'s), hence making DCT very useful for data compression applications.
