Abstract
Self-mixing optical coherent detection is a non-contact measurement technique which provides accurate information about the vibration frequency of any test subject. In this research, novel designs of optical homodyne and heterodyne detection techniques are explained. Homodyne and heterodyne setups are used for measuring the frequency of the modulated optical signal. This technique works on the principle of the optical interferometer, which provides a coherent detection of two self-mixing beams. In the optical homodyne technique, one of the two beams receives direct modulation from the vibration frequency of the test subject. In the optical heterodyne detection technique, one of the two optical beams is subjected to modulation by an acousto-optics modulator before becoming further modulated by the vibration frequency of the test subject. These two optical signals form an interference pattern that contains the information of the vibration frequency. The measurement of cardiovascular signals, such as heart rate and heart rate variability, are performed with both homodyne and heterodyne techniques. The optical coherent detection technique provides a high accuracy for the measurement of heart period and heart rate variability. The vibrocardiogram output obtained from both techniques are compared for different heart rate values. Results obtained from both optical homodyne and heterodyne detection techniques are compared and found to be within 1% of deviation value. The results obtained from both the optical techniques have a deviation of less than 1 beat per minute from their corresponding ECG values.
Highlights
The maximum critical cases across the world are related to chronic cardiorespiratory conditions
The common intention behind this development is to enable the monitoring of cardiovascular parameters, such as heart rate (HR) and heart rate variability (HRV), in scenarios that prevent the use of conventional clinical sensors, normally requiring some sort of direct electrical or mechanical coupling
HR is measured in average beats per minute, while HRV measures the specific
Summary
The maximum critical cases across the world are related to chronic cardiorespiratory conditions. A vast amount of research is available for the measurement of cardiovascular parameters, but most of the research is related to contact type measurement. There is much less clinical awareness of non-contact type optical measurement of cardiovascular parameters. The common intention behind this development is to enable the monitoring of cardiovascular parameters, such as heart rate (HR) and heart rate variability (HRV), in scenarios that prevent the use of conventional clinical sensors, normally requiring some sort of direct electrical (resistive) or mechanical coupling. HRV provides information about the person’s physical and emotional response towards any illness and stress [6]. It can provide important information about blood sugar, blood pressure, digestion, and the respiration cycle. As HRV measurement involves changes in the heart period in the order of milliseconds, it requires higher degrees of accuracy than HR
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
