fig4

Figure 4. Correlation and inconsistency analysis of CF, PPGA, and b/a ratios in wrist extension experiments. (A) PPGA visualization; (B) 3.5-4.5 s interval for b/a ratio calculation; and (C) segmented time intervals (3.5-4.5 s, 11-12 s, 23-24 s, 36-37 s, 44.5-45.5 s) for b/a ratios calculation. PPG: photoplethysmography; CF: contact force; PPGA: PPG amplitude; AC: Alternating current.