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MathGroup Archive 2010

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Re: wavelet

  • To: mathgroup at smc.vnet.net
  • Subject: [mg114719] Re: wavelet
  • From: "Vivek J. Joshi" <vivekj at wolfram.com>
  • Date: Tue, 14 Dec 2010 06:54:47 -0500 (EST)

You need to Map the function over the wavelet coefficients,

data == Sin[N@Range[0, 2 Pi, 2 Pi/1023]] + RandomReal[NormalDistribution[0,0.1], 1024];

dwd == DiscreteWaveletTransform[data,HaarWavelet[],5]
DiscreteWaveletData[<<DWT>>,<5>,{1024}]

Map[#[[1]]->StandardDeviation[Flatten[#[[2]]]]&,dwd[{___,1}]]
{{1}->0.100544,{0,1}->0.106671,{0,0,1}->0.105074,{0,0,0,1}->0.138215,{0,0,0,0,1}->0.249566}

or

StandardDeviation[Flatten[#]]&/@dwd[{___,1},"Values"]
{0.100544,0.106671,0.105074,0.138215,0.249566}

Vivek J. Joshi
Wolfram Research Inc.

On Dec 13, 2010, at 2:50 AM, clansa wrote:

> The order
> StandardDeviation[Flatten[dwd[{___,1},"Values"]]
> compute the standard deviation of all the wavelets coefficients dwd
>
> But I want to calculate standard deviations of the wavelets
> coefficients for each level of the decomposition
> Do you know the solution?
> Thanks
>
> Andre Dauphine, Geographer
>


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