Fig. 4
From: A step in the right direction: an open-design pedometer algorithm for dogs
Illustration of approach used to find falling flank zero crossings and estimate step distance. Points marked are i) Amax, the peak acceleration observed in the dorsal-ventral axis; ii) (Amax - Amin) /2, the mean acceleration observed in the dorsal-ventral axis; iii) Amin, the minimum acceleration observed in the dorsal-ventral axis; iv) collar mounted accelerometer; v) falling flank zero-crossing; vi) “bounce” calculated as Amax-Amin; vii) accelerometer signal aligned with ventral axis of dog (after re-orientation, filtering and smoothing). The figure shows the half angle of the step (ϕ) can be estimated from the trigonometry based around the bounce between steps. Amax and Amin can be used in eq. (4) for calculating step distance