Table 2.

Cell trajectory features and their formulas

Particle motion features
Diffusion coefficient	According to Sbalzarini and Koumoutsakos (2005)
Diffusion adequation	Correlation between MSD(t) and t
Movement type	According to Sbalzarini and Koumoutsakos (2005)
Englobing ball number	See text
Track entropy	See text
Other global features
Convex hull area	—
Effective path length	$L=\left|\right|m_T-m_1|{|}_2$
Effective speed	$L/\sqrt{T}$
Largest move	—
Straightness index	$\sqrt{T}L/P$
Track curvature	See text
Averaged local features
Mean squared displacement (MSD)	$\frac{1}{T-1}{\displaystyle \sum |}|m_t-m_{t-1}|{|}_2^2$
Mean signed turning angle	$\arctan (\frac{\Sigma \sin ({\alpha }_{t+1}-{\alpha }_t)}{\Sigma \cos ({\alpha }_{t+1}-{\alpha }_t)})$

Note: Notations: ${(m_t)}_{t=1\dots T}$, time sequence of cell 2D positions; T, track time duration; P, total track length.