The use of commercially available devices for measurement of physiological signals of drivers

V magistrski nalogi predstavljam rezultate uporabniške študije, v kateri sem primerjal delovanje dveh komercialnih naprav za merjenje fizioloških signalov voznikov. Gre za napravi Empatica E4 in Bittiumov Faros 360, ki omogočata merjenje spremenljivosti srčnega utripa (HRV), a vsaka na svoj način. Empatica uporablja metodo optične pletizmografije (PPG), Faros pa meri EKG signal. Cilj je bil ugotoviti, ali lahko z omenjenima napravama uspešno zaznavamo voznikove odzive na različne situacije v prometu in ločujemo različne ravni zahtevnosti vožnje. Prav tako je bil cilj ovrednotiti enostavnost uporabe posamezne naprave, razpoložljivost pripadajoče programske opreme in možnosti razvoja lastnih aplikacij na osnovi omenjenih naprav. V študiji je sodelovalo 22 oseb (od tega 8 žensk) med 18. in 45. letom starosti. Vsak sodelujoči je prestal tri faze merjenja: vzpostavitev baze oz. mirovanje (5 min), lahka vožnja oz. uvajanje (5 min) ter zahtevna vožnja oz. preizkus (5–10 min). Primerjali smo aritmetično sredino HRV vzorcev, mediano, standardni odklon vseh R–R intervalov (SDNN) in efektivno vrednost zaporednih razlik (RMSSD) HRV vzorcev. Rezultati so pokazali, da z napravo Faros 360 lahko zaznamo statistično pomembne razlike med lahko in zahtevno vožnjo, z Empatico E4 pa le razlike med mirovanjem in premikanjem. Ugotovljena slaba lastnost Empatice E4 je, da med gibanjem ne zazna vsakega udarca srca in posledično podaja nepopolne rezultate meritev. Kljub temu se zaradi možnosti merjenja galvanskega odziva kože (GSR) in robustnega temperaturnega senzorja Empatica E4 v nekaterih primerih izkaže za uporabno napravo. V prihodnosti nas čaka še analiza meritev po časovnih intervalih, s katero bi si želeli zaznati kratkotrajne dogodke, kot so npr. vožnja v ovinek, naglo zaviranje ali trk.In the master\u27s thesis I report on the results of a user study in which I compared the performance of two commercially available devices for measuring drivers\u27 physiological signals. These are Empatica E4 and Bittium\u27s Faros 360 devices, which allow the measurement of heart rate variability (HRV), but each in its own way. Empatica uses the method of photoplethysmography (PPG), Faros measures the ECG signal. The goal was to determine if these two devices can successfully detect the drivers\u27 responses to different traffic situations and distinguish between different level of driving difficulty. The goal was also to evaluate the ease of using a particular device, the availability of the associated software and the possibility of developing custom applications for these devices. The study involved 22 participants (of which 8 were female) between 18 and 45 years of age. Each had to pass three phases of measurement: baseline establishment (5 min), easy driving (5 min) and demanding driving (5 – 10 min). We compared the arithmetic mean of HRV samples, median, standard deviation of all R–R intervals (SDNN) and root mean square of successive differences (RMSSD) of HRV samples. The results showed that the Faros 360 device can detect statistically significant differences between easy and demanding driving and Empatica E4 device only the differences between baseline (hibernation) and movement. Noteable weakness of Empatica is that it does not detect every heart beat during movement and consequently gives incomplete measurement results. Nevertheless, due to the possibility of measuring the galvanic skin response (GSR) and a robust temperature sensor, Empatica E4 may in some cases prove to be a usable device. In the future we are performing an analysis of the measurements, separated by time intervals. We would like to detect short-term events, such as, for example, bumping, sudden breaking or collision