Spatio-temporal and -spectral feature maps in photoplethysmography imaging and infrared thermography

Table 6 Cumulative processing times for the maps and a selection of processing steps. The average time based on the calculation of one partitioned video segment is reported. Cumulative times are shown, i.e., including preprocessing times of mean subtraction, filtering, windowing, FFT and PS calculation, respectively

Map/processing step	Time series [\(\upmu\)s]	Map 376\(\times\) 232 [s]	Map 608 \(\times\) 448 [s]
Mean intensity	0.13	0.01	0.03
Band power	26.26	2.29	7.15
Band mean power	26.27	2.29	7.16
Band max/band power	26.38	2.30	7.19
Spectral centroid	26.79	2.34	7.30
Spectral spread	27.60	2.41	7.52
Spectral skewness	30.75	2.68	8.38
Spectral kurtosis	28.05	2.45	7.64
Spectral crest	26.41	2.30	7.19
Spectral flatness	27.61	2.41	7.52
Spectral entropy	27.95	2.44	7.61
Spectral slope	27.20	2.37	7.41
Max frequency	26.34	2.30	7.17
Phasor phase	17.73	1.55	4.83
Phasor amp	17.72	1.55	4.83
Temporal var	12.46	1.09	3.39
Spectral flux pos	53.72	4.69	14.63
Spectral flux neg	53.72	4.69	14.63
Ratio flux pos	53.90	4.70	14.68
Ratio flux neg	53.90	4.70	14.68
PS	19.01	1.66	5.18
Mean subtract	0.13	0.01	0.04
Filter	5.70	0.50	1.55
Windowing	1.25	0.11	0.34
FFT	10.41	0.91	2.84

ISSN: 1475-925X