Matlab - Signal Noise Removal

Question

I have a vector of data, which contains integers in the range -20 20.

Bellow is a plot with the values:

Answer 1

To eliminate the low amplitude peaks, you're going to equate all the low amplitude signal to noise and ignore.

If you have any apriori knowledge, just use it.

if your signal is a, then

a(abs(a)

where X is the max expected size of your noise.

If you want to get fancy, and find this "on the fly" then, use kmeans of 3. It's in the statistics toolbox, here:

http://www.mathworks.com/help/toolbox/stats/kmeans.html

Alternatively, you can use Otsu's method on the absolute values of the data, and use the sign back.

Note, these and every other technique I've seen on this thread is assuming you are doing post processing. If you are doing this processing in real time, things will have to change.