Identifying Peaks and their Rate of Change

[Matthias]

Hello everybody,

I am very new to SEEQ and have the following problem/question:

I would like to identify each maximum peak of the blue curve (shown below in the figure). Then I would like to compare each maximum peak's value - meaning something like the rate of change of lets say one peak and the upcoming peak. In the end I want to detect a significant change of the signal (marked by red X's) and would like to know its duration (marked by the red arrows).
 

Thank you.

Regards Matthias

[Siti Tay]

Hi Matthias, 

The first question is to identify each maximum peak of the blue trend : 

1. First apply an agileFilter to remove noisy signal and calculate the derivative of the signal. Please refer to formula documentation for derivative. Example: 

$signal.agileFilter(15min).derivative('min')

2. Then use value search to identify increasing trend, example as below and you can optimize accordingly. 

or you can refer to step 4 and 5 from this post : 

3. Use Signal from condition to find the maximum value bounded to the condition created in step 2 and place the timestamp at point of max value: 

 

Second Question : Rate of change of one peak and the upcoming peak

4.  We can apply the same derivative function. Example: 

$max.derivative('min')

 

Third Question : to detect a significant change of the signal (marked by red X's)

5. The max derivative will increase or decrease significantly when there's a sudden change. Example here, we're using the threshold of +-0.005 to detect the changes for max rate decrease and increase respectively. 

 

Forth Question : to know its Duration (marked by the red arrows) : 

6. Use Composite condition to join ''Rate Decreased'' and ''Rate Increased"

8. Calculate Total Duration of ''Join Decreased to Increased'' condition using signal from condition tool. 

Please give this a try to your signal and let us know if you have further question. 

 

 

[Matthias]

Wow! Very good description and explanation! Thank you very much - it worked for me.