Discrete cosine transform
= Discrete cosine transform
{wiki}
The type-II discrete cosine transform of $x_0,\ldots,x_{N-1}$ is
$$
Z_k=\sum_{n=0}^{N-1}x_n\cos\left(\frac{\pi}{N}\left(n+\frac12\right)k\right).
$$
= Discrete cosine transform
{wiki}
The type-II discrete cosine transform of $x_0,\ldots,x_{N-1}$ is
$$
Z_k=\sum_{n=0}^{N-1}x_n\cos\left(\frac{\pi}{N}\left(n+\frac12\right)k\right).
$$