LastWave Package Extrema1d 2.0 Authors Description Examples



Package allowing to deal with 1d wavelet transform local extrema


Let's run the Demo DemoExtrema1dSing

Let's run the Demo DemoExtrema1dSing
Here is the code of the demo:
# Set the current wavelet transform to be a
# Generate the signal (a singularity of Holder .5)
0 = [_DemoSing 10000 .5]
# Adds noise to it
0= 0a+.02*Grand
# Compute the wavelet transform
cwtd 3 6 8 'g1'
# Compute the extrema representation
# Display the signal, the wavelet transform and the extrema representation
disp 0 a a.extrep

If you zoom one of the graph (using the mouse or the command line) everything is zoomed:

Then you can select a maxima line and draw the log(values) of the wavelet transform along this line (using sift+left mouse button). Then you can perform a linear fit in order to obtain an estimation of the Holder exponent