Basis functions in DCT

1. What are basis functions in DCT?
2. How does DCT compression work?
3. What is DCT function in Matlab?
4. Why DCT is used in MFCC?

What are basis functions in DCT?

The DCT is an invertible transform, and its inverse is given by. The inverse DCT equation can be interpreted as meaning that any M-by-N matrix A can be written as a sum of functions of the form. These functions are called the basis functions of the DCT.

How does DCT compression work?

The DCT works by separating images into parts of differing frequencies. During a step called quantization, where part of compression actually occurs, the less important frequencies are discarded, hence the use of the term “lossy.

What is DCT function in Matlab?

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.

Why DCT is used in MFCC?

DCT is the last step of the main process of MFCC feature extraction. The basic concept of DCT is correlating value of mel spectrum so as to produce a good representation of property spectral local. Basically the concept of DCT is the same as inverse fourier transform.