Cross Time-Frequency Analysis for Combining Information of Several Sources: Application to Estimation of Spontaneous Respiratory Rate from Photoplethysmography

Figure 2

Cross TF spectra between: (a) PIV—PAV signals, (b) PIV—PWV signals, (c) PAV—PWV signals. Instantaneous frequencies 𝑓_𝑘^𝑖𝑗(𝑡) are reported in black lines. Black contours encircle the TF regions of the respiration-related component Ω^𝛼_{𝑖𝑗,𝑘}. Horizontal lines represent 𝑓_𝑀.

(a) |𝑆^PIV,PAV₁(𝑡,𝑓)|

(b) |𝑆^PIV,PWV₂(𝑡,𝑓)|

(c) |𝑆^PAV,PWV₃(𝑡,𝑓)|