KLT vs DCT basis restriction error

1. Is DCT better than DFT?
2. Why DCT is used instead of DFT?
3. What is a DCT basis?
4. Is DCT The real part of DFT?

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.

What is a DCT basis?

July 2022) 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.

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.