Discrete Cosine Transform

1. What does discrete cosine transform?
2. Why discrete cosine transform is used?
3. What is discrete cosine transform in image processing?
4. What is the difference between DFT and DCT?

What does discrete cosine transform?

Definition:Discrete Cosine Transform is a technique applied to image pixels in spatial domain in order to transform them into a frequency domain in which redundancy can be identified.

Why discrete cosine transform is used?

Discrete Cosine Transform is used in lossy image compression because it has very strong energy compaction, i.e., its large amount of information is stored in very low frequency component of a signal and rest other frequency having very small data which can be stored by using very less number of bits (usually, at most 2 ...

What is discrete cosine transform in image processing?

DCT Definition

The discrete cosine transform (DCT) represents an image as a sum of sinusoids of varying magnitudes and frequencies. The dct2 function computes the two-dimensional discrete cosine transform (DCT) of an image.

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.