Howtosignalprocessing
- Why DCT is better than DFT in compression?
- Which is better DCT or DFT?
- Why is DCT preferred for image compression?
- What is the relation between DCT and DFT?
Why DCT is better than DFT in compression?
> 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.
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).
Why is DCT preferred for image compression?
The DCT can be used to convert the signal (spatial information) into numeric data ("frequency" or "spectral" information) so that the image's information exists in a quantitative form that can be manipulated for compression. The signal for a graphical image can be thought of as a three-dimensional signal.
What is the relation between DCT and DFT?
DCT is similar to the Discrete Fourier Transform (DFT), but using only real numbers. DCT are equivalent of DFT of roughly twice the length, operating on real data with even symmetry and in some variants the input or output data are shifted by half a sample.
