TOPICS
Search

Haar Wavelet


The Haar wavelet is the compactly supported wavelet

 psi(x)={1   0<=x<1/2; -1   1/2<=x<1; 0   otherwise.
(1)

Its dyadic rescalings, which are the function-space analogs of geometric dilations, and its integer translations

 psi_(j,k)(x)=2^(j/2)psi(2^jx-k),
(2)

for j,k in Z form an orthonormal basis of L^2(R). The factor 2^(j/2) preserves the L^2 norm under this rescaling. The Haar wavelet is discontinuous but has zero mean, since int_(-infty)^inftypsi(x)dx=0.

The Wolfram Language represents the Haar wavelet by HaarWavelet[] and computes a discrete Haar transform using DiscreteWaveletTransform[data, HaarWavelet[]].


See also

Haar Function, Haar Transform, Orthonormal Basis, Wavelet, Wavelet Transform

Explore with Wolfram|Alpha

References

Haar, A. "Zur Theorie der orthogonalen Funktionensysteme." Math. Ann. 69, 331-371, 1910. https://doi.org/10.1007/BF01456326.

Cite this as:

Weisstein, Eric W. "Haar Wavelet." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/HaarWavelet.html

Subject classifications