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matlabreal-timesignal-processing

Matlab: Peak detection for clusters of peaks

I am working with biological signal data, and am trying to count the number of regions with a high density of high amplitude peaks. As seen in the figure below, the regions of interest (as observed qualitatively) are contained in red boxes and 8 such regions were observed for this particular trial. The goal is to mathematically achieve this same result in near real time without the intervention or observation of the researcher.

The data seen plotted below is the result of raw data from a 24-bit ADC being processed by an FIR filter, with no other processing yet being done.

Signal Data

What I am looking for is a method, or ideally code, to help me detect such regions as identified while subsequently ignoring some of the higher amplitude peaks in between the regions of interest (i.e. between regions 3 and 4, 5 and 6, or 7 and 8 there is a narrow region of high amplitude which is not of concern). It is worth noting that the maximum is not known prior to computation.

Thanks for your help.

Data
https://www.dropbox.com/s/oejyy6tpf5iti3j/FIRData.mat

Solution

  • can you work with thresholds?

    define: (1) "amplitude threshold": if the signal is greater than the threshold it is considered a peak

    (2) "window size" : of a fixed time duration

    algorithm:

    if n number of peaks was detected in a duration defined in "window size" than consider the signal within "window size" as cluster of peaks.(I worked with eye blink eeg data this way before, not sure if it is suitable for your application)

    P.S. if you have data that are already labelled by human, you can train a classifier to find out your thresholds and window size.