Mexican hat wavelet
[PSI,X] = mexihat(LB,UB,N)
[PSI,X] = mexihat(LB,UB,N) returns values of the Mexican hat wavelet on an N point regular grid, X, in the interval [LB,UB].
Output arguments are the wavelet function PSI computed on the grid X.
This wavelet has [-5 5] as effective support. Although [-5 5] is the correct theoretical effective support, a wider effective support, [-8 8], is used in the computation to provide more accurate results.
This function is proportional to the second derivative function of the Gaussian probability density function.
% Set effective support and grid parameters. lb = -5; ub = 5; n = 1000; % Compute and plot Mexican hat wavelet. [psi,x] = mexihat(lb,ub,n); plot(x,psi), title('Mexican hat wavelet')