Figure 3.

Illustration of high-level pipeline showing labeling used in this study. The continuous B-mode ultrasound recordings are segmented based on prerecorded heel strikes. The individual chucks are then processed using the affine optical flow algorithm of UltraTrack [25] to extract the fascicle lengths in millimeters (mm) across time in seconds (s) (in the lower left box). Each segmented sequence has many fascicle lengths (on average 130 frames in each segmented sequence), which form the fascicle lengths over time waveforms (left blue box). Finally, to validate the accuracy of the labeling methodology, the extracted individual segments of fascicles are plotted on top of each other over the stance phase (in the right box) following the approach proposed by Lai et al. [37].