Function File: y = idct (x) ¶

Function File: y = idct (x, n) ¶

Compute the inverse discrete cosine transform of x. If n is given, then x is padded or trimmed to length n before computing the transform. If x is a matrix, compute the transform along the columns of the the matrix. The transform is faster if x is real-valued and even length.

The inverse discrete cosine transform x can be defined as follows:

         N-1
  x[n] = sum w(k) X[k] cos (pi (2n+1) k / 2N ),  n = 0, ..., N-1
         k=0

with w(0) = sqrt(1/N) and w(k) = sqrt(2/N), k = 1, ..., N-1

See also: dct, dct2, idct2, dctmtx.

Package: signal