Howtosignalprocessing
What is basis function in DCT?
The inverse DCT equation can be interpreted as meaning that any M-by-N matrix A can be written as a sum of MN functions of the form. α p α q cos π ( 2 m + 1 ) p 2 M cos π ( 2 n + 1 ) q 2 N , 0 ≤ p ≤ M − 1 0 ≤ q ≤ N − 1. These functions are called the basis functions of the DCT.
What is DCT coefficients?
DCT coefficient (0,0) is the DC coefficient, or average sample value. Since natural images tend to vary only slightly from sample to sample, low frequency coefficients are typically larger values and high frequency coefficients are typically smaller values. The 8×8 DCT is defined in Figure 5.21.
What is the difference between DCT and FFT?
The difference between a Discrete Fourier Transform and a Discrete Cosine transformation is that the DCT uses only real numbers, while a Fourier transform can use complex numbers. The most common use of a DCT is compression. It is equivalent to a FFT of twice the length.
