Figure 30.

Zero-crossings method exemplified in a real signal obtain from the public breathing dataset of Vanegas et al. [254]. (A) Effect of the presence of outliers in the signals in the calculation of the “zero level”. (B) Example of a signal with trends and results of applying a de-trend processing. (C) Example of using different “zero levels” in a signal with trends. (D) Example of a noisy signal with several zero-crossings detected when only one of them (green) should have been considered.