3582428419

09/10/2015 peakdet Pe^ detection using MATLA8(noo-dern/3tive local extremum. maximum. minimum)

09/10/2015 peakdet Pe^ detection using MATLA8(noo-dern/3tive local extremum. maximum. minimum)

•    Home

•    CV

•    CV (hebrew)

•    FPGA Editor

•    Free software

•    Lectures

•    Perlilog

•    Eobj

•    frandom

•    cdepend

•    hitec (LaTeX)

•    easyspec

•    peakdet

•    FIFO tricks

•    CDCE906

•    Optical Simulator

•    HTML highlighting

•    Hobbies

•    Tech blog

peakdet: Peak detection using MATLAB

Here's a problem I encounter in several fields: Find the local maxima and minima in some noisy signal, which typically looks like the following graph:

The local maxima and minima are plotted as red and green stars on the graph. To the eye it's so obvious where they are, but making a Computer find them can turn out tricky.

Let's start with what not to do: Using the well-known zero-derivate method. Due to the noise, which is always there in reaHife signals, acddental zero-crossings of the first derivate occur, yielding false detections. The typical solution is to smooth the curve with some low-pass fil ter, usually killing the original signal at the same time. The result is usually that the algorithm goes horribly wrong where it's so obvious to the eye.

In many cases, we don't really care about maxima and minima in the mathematical sense. We can see the peaks and valleys, and we want the Computer to find them. This is what "peakdet" does.

The tri dc here is to realize, that a peak is the highest point betweem

httpyAwAv.billauei.co.il/peakdethtml

1/3