Table 1.

Scalar measures quantifying spatial and temporal changes of WSS derived from WSS angle, magnitude, and vector. Relative measures are defined by dividing the variation by WSS magnitude. All of the measures would be averaged temporally. Prime denotes temporal gradient ($\prime =d/dt$). For $\Vert \nabla \mathit{\tau }\Vert$ the induced L₂ (spectral) norm was used.

	Space	Time
Angle	$\Vert \nabla \theta \Vert$	$\theta \prime$
Magnitude	$\Vert \nabla \Vert \mathit{\tau }\Vert \Vert$	$\Vert \mathit{\tau }\Vert \prime$
Vector	$\Vert \nabla \mathit{\tau }\Vert$	$\Vert \mathit{\tau }\prime \Vert$
Relative	$\frac{\Vert \nabla \mathit{\tau }\Vert }{\Vert \mathit{\tau }\Vert }$	$\frac{\Vert \mathit{\tau }\prime \Vert }{\Vert \mathit{\tau }\Vert }$