Let's say I have a line graph with a $1-\text{minute}$ moving average as pictured below.
I would like to use a script find the $X'd$ positions on the line. The $X's$ represent beginnings of changes in momentum/direction.
Is there an algorithm or mathematical formula(s) to accomplish this? Perhaps a combination of standard deviation and slope?
It seems to me that you are looking for points with zero curvature.