Evaluation of Performance of an Optical Heart Rate Sensor
Haavikko, Aleksi (2014)
2014
Automaatiotekniikan koulutusohjelma
Tieto- ja sähkötekniikan tiedekunta - Faculty of Computing and Electrical Engineering
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2014-12-03
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201412041575
https://urn.fi/URN:NBN:fi:tty-201412041575
Tiivistelmä
Older technologies, which might have been the golden standard in the industry for years, are rapidly becoming available to a wider audience as manufacturing methods become easier and cheaper. Companies are able to provide every consumer the same devices which have been the privilege of only the professional field. This has also been the case with fitness wearables, of which one subclass is the optical heart rate sensors. The goal of this thesis was to evaluate the performance of one such device, namely the PulseOn wrist device.
The device utilizes photoplethysmography (PPG) in acquiring the heart rate signal. PPG has been used in clinical settings for oxygen saturation level determination, but the technology can also provide other figures from the cardiovascular system, such as heart rate. The measurement method is based on the detection of light, which is emitted into the skin and then interacts with the tissue. The composition of the blood vessels changes in synch with the beating of the heart, and so does the intensity of the detected light.
The PulseOn device was tested in controlled laboratory conditions with 20 subjects. The measurement protocol included periods of rest and activities of varying intensities. A reference measurement was made simultaneously with a Polar heart rate belt, and also two other devices were used to record data for later assessments.
The results were analysed in MATLAB, and values for heart rate reading reliability and measurement errors were calculated. For example, the correlation of the PulseOn device against the Polar belt was found to be approximately 96 %, the amount of readings that were within 10 % of the values given by the heart rate belt was 90.4 %, and the average value of the absolute errors between the two devices was 4.76 beats per minute.
Even though the PulseOn device was still in its development phase at the time of the measurements, it showed satisfactory results, and that it could be used in the heart rate measurements of everyday fitness activities.
The device utilizes photoplethysmography (PPG) in acquiring the heart rate signal. PPG has been used in clinical settings for oxygen saturation level determination, but the technology can also provide other figures from the cardiovascular system, such as heart rate. The measurement method is based on the detection of light, which is emitted into the skin and then interacts with the tissue. The composition of the blood vessels changes in synch with the beating of the heart, and so does the intensity of the detected light.
The PulseOn device was tested in controlled laboratory conditions with 20 subjects. The measurement protocol included periods of rest and activities of varying intensities. A reference measurement was made simultaneously with a Polar heart rate belt, and also two other devices were used to record data for later assessments.
The results were analysed in MATLAB, and values for heart rate reading reliability and measurement errors were calculated. For example, the correlation of the PulseOn device against the Polar belt was found to be approximately 96 %, the amount of readings that were within 10 % of the values given by the heart rate belt was 90.4 %, and the average value of the absolute errors between the two devices was 4.76 beats per minute.
Even though the PulseOn device was still in its development phase at the time of the measurements, it showed satisfactory results, and that it could be used in the heart rate measurements of everyday fitness activities.