Re: autocorrelation
- To: mathgroup at smc.vnet.net
- Subject: [mg44381] Re: autocorrelation
- From: Mariusz Jankowski<mjankowski at usm.maine.edu>
- Date: Fri, 7 Nov 2003 05:16:27 -0500 (EST)
- Organization: University of Maine System testbed server
- References: <bo5sst$p1$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Mikael, use ListCorrelate, it is substantially faster. Specifically, if x is your image matrix the following will return all the autocorrelation coefficients assuming zero padding at the borders.
ListCorrelate[x,x,{1,1},0]
If you do not need all the coefficients, but only the first nr rows and nc columns, then use
ListCorrelate[x,x,{nr,nc},0]
Mariusz
>>> Mikael L<lassenmikael at kabelnettet.dk> 11/3/2003 10:40:13 AM >>>
Hi
I have some tiff images where I have to make autocorrelation on. I have
tried it but I think that math. is very slow.
The images/matrix is 480x360 pixels.
I am using fourier transformation and inversfourier transformation to make
the autocorrelation.
Is there any body that has experience with this using mathematica?
best regards
Mikael