wave normalization

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Hi All

i've been looking on the old posts but could find anything which really fits to my proble.
So i have different waves of different intensity and i would like to display their different intensities
on the same scalenot just by normalizing them but in a way that the min and max of each waves are
displayed in the same scale (e.g. from 0 to 1). with usual normalization you usually heve the maxima
all to 1 but then the rest of the other waves may not be easily compared, i would like that each of my waves are displayed in the
same scale. how could i do that?
thanks for your help
Does your data have a baseline? This should be subtracted prior to normalizing the curves.

April 1, 2013 at 09:20 am - Permalink

I have some simple macro's that I use when I have to try and get all data on the same scale.
macro NormalizeToH()
string list;
string name;
variable i;
variable peakArea
   
    list=WaveList("*",";","");
    i=0;
    do
        name=StringFromList(i,list);
        wavestats /q $name
        $name/=V_max;
        i+=1;
    while (1);
end

If you modified this to also subtract off V_min first and then divide by (V_Max-V_Min) then it might do what you want.

April 1, 2013 at 10:58 am - Permalink

Here is another approach which I use often:
Function NormTo1(inwave)
    Wave inwave
    Variable normval
    normval = wavemin(inwave)
    inwave -= normval
    normval = wavemax(inwave)
    inwave /= normval
End

Just select the waves you like to normalize inside the Data Browser and press the 'Exec. Cmd...' button. In the appearing window write Normto1(%s) and press ok.

April 1, 2013 at 12:52 pm - Permalink

Hi Guys
thanks again for your useful suggestions, they have helped me out a lot.

cheers

April 2, 2013 at 04:24 am - Permalink

You'll want to be careful using Chozo's method if your data is prone to noise as the minimum value could be well below the baseline background signal. Of course this is highly dependent on the data you are working with.

In my case, I define a region of data that represents the background, take the mean of this data range and subtract it from the data, instead of just the min. Of course this is because my waves usually have a zero value near the start or end of the wave.

April 2, 2013 at 06:37 am - Permalink