Influence of magnitude notch filter on calculated mean velocities

[Marco]

Hello William,

I want to calculate mean velocities and exclude small velocities from the calculation. For that i used the magnitude noch filter to exclude velocities from 0 to 0.08 m/s, but in the mean frame there are velocities smaller than 0.08. What's the reason for this and how could i solve this problem? 

In my experiment there are negative velocities in both directions (v and u). I thought it could this could be the problem and may lead to skewed calculated averages, but I already tried to exclude velocities from negative velocities to 0.08 m/s and it also didn't work. Maybe the appearing NaN vector values are the problem?

Best Regards

Marco

[William]

Hi,

the mean is calculated from the analyzed fames. If at one position, there is a velocity of 0.1 in one frame, and in the next frame there is -0.05 at this position, then the average frame will report 0.025 at this position. If you want to exclude the velocity range of 0 to 0.08 also in the mean frame, then just apply the same validation again to the mean frame.