Find the starting and ending points of a sudden change in time series data.

Hello all,

I am new to MATLAB and need some help with a time series data. Our machine records average diameter of eye almost 240 times a second for 3 to 5 minutes. When we plot the data, we sometimes get artifacts(say something like a blink or an eye movement.). I need to find the starting and the ending points of the artifacts, so that I can remove the blink with a slope of the points.

Attached are the pictures of data plotted, where the 'y'axis - diameter, 'x'axis= total no of recorded points.

please help me.

Example of data values -

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Answer 1

[Image Analyst]

I'd try filtering it with a Savitzky Golay filter, sgolayfilt(), and then computing residuals = abs(signal - filteredSignal). If any elements have a bigger than expected residual, either replace with the filtered signal or Nan's or something.

[Satish Tadepalli]

Thank you great idea.