wavelets dsp for noobs?

Nov 20, 2011 at 9:04 PM

Hello,

I am trying tu use wavelets dsp on a signal from a Kinect sensor (the joint positions not the video stream).

I'm not a good programmer, i  tried to use the documentation but that did not get me very far with my little skills.

I am not going for anything complicated : signal (approx 1000 datapoints in an array of real) -> Wavelet signal analysis -> graphical view of wavelet analysis.

Help would be appreciated or an example to get me on the right track

Thanks

 

 

 

 

 

 

Coordinator
Nov 21, 2011 at 8:39 PM

Hello sambafr,

Do you already have the program to collect data from the kinect sensor?
If so, you can add the following lines to get the DWT from the signal (in C# 4.0/Visual Studio 2010):

....
using WaveletStudio.Functions;
using WaveletStudio.Wavelet;
....
var samples = new double[] { 5, 6, 7, 8, 1, 2, 3, 4 };
var signal = new Signal(samples);
var wavelet = MotherWavelet.LoadFromName("daub4");
var output = DWT.ExecuteDWT(signal, wavelet, 2, SignalExtension.ExtensionMode.SymmetricHalfPoint);
foreach (var level in output)
{
var approximation = level.Approximation;
var details = level.Details;

//you use the approximation and details' coefficients here...
}
.....

You can also use the GUI program included with Wavelet Studio to do this graphically. Use the WaveletStudio.MainApplication.exe program.
It doesn't have a block to collect data from the kinect sensor, but it's very easy to use it to analise any signal. 
Add the "Text" and "DWT" blocks, connect both and set its properties. You'll see the DWT result clicking on the block...
Nov 28, 2011 at 2:30 PM

Hello,

Thanks for your help, i have progressed using the library but i still have questions.

For FFT:

Is it possible to use an FFT block on a signal (eg an array of double like for DWT), or do we have to import a csv file?

I have trouble because blocks use "." to mark decimals and wpf or other programms use "," therefore i must convert to string and replace the points in commas. IS there a way to use "," as decimal markers in the blocks?

If i enter a real array as signal in the FFTblock i get some négative results. in the csvexportblock. How do i get access to the real part of the fft ?

For DWT, everyhting seems to work fine, thanks.

If i am not clear i can post my code,. Thanks for your help