DCT Based modelling

1. What is DCT method?
2. What is the difference between DFT and DCT?
3. Is DCT better than DFT?
4. Why DCT is used instead of DFT?

What is DCT method?

A discrete cosine transform (DCT) expresses a finite sequence of data points in terms of a sum of cosine functions oscillating at different frequencies. The DCT, first proposed by Nasir Ahmed in 1972, is a widely used transformation technique in signal processing and data compression.

What is the difference between DFT and DCT?

The DFT is actually one step in the computation of the DCT for a sequence. The DCT, however, has better energy compaction than the DFT, with just a few of the transform coefficients representing the majority of the energy in the sequence.

Is DCT better than 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.

Why DCT is used instead of DFT?

> DCT is preferred over DFT in image compression algorithms like JPEG > because DCT is a real transform which results in a single real number per > data point. In contrast, a DFT results in a complex number (real and > imaginary parts) which requires double the memory for storage.