Mexican hat wavelet
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In mathematics and numerical analysis, the Mexican hat wavelet is the normalized, second derivative of a Gaussian function. It is a special case of the more general family of continuous wavelets (wavelets used in a continuous wavelet transform) known as Hermitian wavelets.
- <math>\psi (t) = \left( {2 \over {\sqrt 3 }}\pi^{- {1 \over 4} } \right) \left( 1-t^2 \right)e^{ - {t^2} \over 2 }</math>
The hyperdimensional generalization of this wavelet is called the Laplacian of Gaussian function. In practice, this wavelet is often approximated by the Difference of Gaussians function, as it is easier to compute.