Talk:Ricker wavelet

message: Is it necessary to name this as the Mexican Hat Wavelet? It's more recognizable name is the Ricker Wavelet so perhaps this should be the official name. Chris Engelsma ■ 18:04, 20 October 2011 (UTC)
replies: text: I agree with this. Ricker Wavelet is a much more common name. I have not heard Mexican Hat Wavelet in any place other than here. All publications I have read call it Ricker. 129.7.231.237 (talk) 06:52, 12 April 2012 (UTC)

text: This function is referred to as the Mexican hat function in the image processing and computer vision communities. In these areas, this is an established terminology. I have also seen a number of mathematicians using this terminology. Therefore, a redirect from Richer Wavelet may be more appropriate.  I have never heard of Ricker wavelet before this occasion now, however. Tpl (talk) 09:38, 14 April 2012 (UTC)
thread_title:  Renaming to Ricker Wavelet 

message: Is the normalizing term correct there? i have coded this in matlab:
excit_function=sprintf('(1-((t-%e).^2/%e.^2)).*exp(-(t-%e).^2/(2*%e.^2))',5*ex_sigma,ex_sigma,5*ex_sigma,ex_sigma);
t=0:dt:sim_time;
excit=eval(excit_function);
which is without the normalizing term and it correctly evaluates so that peak is +1 and not something like +10^27  —Preceding unsigned comment added by 188.220.32.144 (talk) 20:59, 25 February 2010 (UTC)
thread_title:  normalizing term 

message: This looks a lot like the kernel of Lanczos resampling. Is this just a superficial relationship? —Ben FrantzDale (talk) 21:32, 31 December 2007 (UTC)
thread_title:  Lanczos resampling 

message: This is 1-dimensional wavelet. It depends on one variable t:
:\psi(t) = {2 \over {\sqrt {3\sigma}\pi^{1 \over 4}}} \left( 1 - {t^2 \over \sigma^2} \right) e^{-t^2 \over 2\sigma^2}
This is 2-dimensional wavelet. It depends on two variables: x, y:
:\psi(x,y) = -\frac{1}{\pi\sigma^4}\left(1-\frac{x^2+y^2}{2\sigma^2}\right) \mathrm{e}^{-(x^2+y^2)/2\sigma^2}.
The image itself is 3d, but what it depicts is a 2d wavelet.  — Preceding unsigned comment added by Eloquent2013 (talk • contribs) 09:06, 24 December 2015 (UTC)
thread_title:  Is second image 3D or 2D? 

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thread_title:  External links modified (January 2018) 

message: We are going to need the Fourier transform of that Ricker somewhere in the article too please.
2600:1700:4CA1:3C80:F012:B463:3E65:F44D (talk) 03:20, 21 November 2018 (UTC)
thread_title:  FT of that 

message: I actually attempted to plot the first equation and I'm not sure it's a Ricker wavelet.
I did find this function which made the sombrero like shape in this paper:
https://pdfs.semanticscholar.org/b5a1/883862382c592e2face697bab9f99f94be64.pdf
ricker (omega, x)=
  (1 - ((1/2)*(omega**2)*(x**2))) * exp ((-1/4)*(omega**2)*(x**2))  — Preceding unsigned comment added by Ianmbloom (talk • contribs) 16:48, 16 February 2022 (UTC)
thread_title:  Not sure about the first equation.