How to find peaks in 1d array

Question

I am reading a csv file in python and preparing a dataframe out of it. I have a Microsoft Kinect which is recording Arm Abduction exercise and generating this CSV file.

I have this array of Y-Coordinates of ElbowLeft joint. You can visualize this here. Now, I want to come up with a solution which can count number of peaks or local maximum in this array.

Can someone please help me to solve this problem?

Answer 1

You can use the find_peaks_cwt function from the scipy.signal module to find peaks within 1-D arrays:

from scipy import signal
import numpy as np

y_coordinates = np.array(y_coordinates) # convert your 1-D array to a numpy array if it's not, otherwise omit this line
peak_widths = np.arange(1, max_peak_width)
peak_indices = signal.find_peaks_cwt(y_coordinates, peak_widths)
peak_count = len(peak_indices) # the number of peaks in the array

More information here: https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.find_peaks_cwt.html

Answer 2

It's easy, put the data in a 1-d array and compare each value with the neighboors, the n-1 and n+1 data are smaller than n.

Read data as Robert Valencia suggests

   max_local=0
for u in range (1,len(data)-1):

if ((data[u]>data[u-1])&(data[u]>data[u+1])):
                            max_local=max_local+1