Despiking

This function remove spike noise from data.

Description

This function remove spike noise from data. This function originally wrote for removing spike noise in time-series water velocity data but can be used for general purpose. The basic idea comes from Goring and Nikora (2002) which considers first and second derivatives of time series signal. See detail in the reference.

Referece
- Mori, N., T. Suzuki and S. Kakuno (2007) Noise of acoustic Doppler velocimeter data in bubbly flow, Journal of Engineering Mechanics, American Society of Civil Engineers, Volume 133, Issue 1, pp.122-125.

• MATLAB release: MATLAB 7.2 (R2006a)

[D. Januar]

Works realy fine with 3D face data, but some interpolation algorithm for filling the holes would be fine!

[landulfo Silveira]

The algorithm leaves NAN symbols in the place of removed spikes. I coudn't use it.

[Evaggelos Karvounis]

Dear Mr. Nobuhito,

Could you please send me the paper again. There were errors when i was
trying to open the pdf gile.

Send it as a pdf and in a zip file if its possible.

Thanks in advance...

Evaggelos Karvounis, PhD

[Jac Billington]

Is there anyway I can get round the use of nanmean for this? I don't have the statistical toolbox in order to use this.

It would be great if you could offer some advice, still pretty new to Matlab.

thanks in advance. Jaclyn.

[Georg Stillfried]

Jac Billington

write your own nanmean function, e.g.:

function m = nanmean (x)
x = x(~isnan(x))
m = mean(x)

[Georg Stillfried]

P.S. I just noticed that this works only if x is a vector. If x is an array, the "official" nanmean will calculate the mean columnwise or along a specified dimension. What they do there is to set the NaNs to zero, sum up the columns and divide by the number of no-NaNs:

function m = nanmean (x,dim)
if nargin<2, dim=1; end
nans = isnan(x);
x(nans) = 0;
sumx = sum(x,dim);
m = sumx./sum(~nans);

Save the file as nanmin.m in a directory on the Matlab path.

hope this helps,
GS

[Shan]

So far it works fairly well for my seismic data, even though it might take some of the valid signals as spikes as well. Still, I am amazed by the quite accurate targeting this this function. Excellent work!

[santa teo]

doesnt work

[Christian Stranne]

Great for despiking ADCP data!

[Frank]

Using this function set for a custom MatLab based ADV signal processing toolset I made. Exactly what I needed. So glad I didn't have to write this myself. Works great!
Thx!