A novel sensor for wrist based optical heart rate monitor
01 May 2017-pp 1-6
TL;DR: A novel 590 nm (yellow-orange) wavelength based optical system is tailored suitably to maximize the signal quality acquired and holds an advantage over its shorter counterpart when subjected to varied skin pigmentation levels.
Abstract: The growing demands of continuous healthcare and hence physiological monitoring necessitates a system with high reliability and accuracy. Wearable used for continuous cardiological parameter estimation from wrist use reflective photoplethysmography technique that has certain limitations which are imperative. One such constraint is skin pigmentation of the subject. In the present work a sensor module design is proposed addressing to the anomalies due to optical properties of skin. A novel 590 nm (yellow-orange) wavelength based optical system is tailored suitably to maximize the signal quality acquired. The proposed setup is validated on a conglomeration of subjects in terms of age, gender and skin tone. A generous agreement between coherent measures for signal quality shows that the proposed wavelength holds an advantage over its shorter counterpart when subjected to varied skin pigmentation levels. A maximum improvement factor of 71 is observed in case of perfusion index, 31 for pulsatile strength and 3 for SNR. The details of sensor design, experimental setup, validation protocol, observations and inferences drawn from the study are presented.
Citations
More filters
TL;DR: This review is focused on heart rate measurement methods located on forearm and more specifically on the wrist, and the superposition of motion artefacts over the signal of interest is one of the largest drawbacks for these methods, when used out of laboratory conditions.
Abstract: When evaluating general health condition on a patient, heart rate is an essential indicator as it is directly representative of the cardiac system state. Continuous measurement methods of heart rate are required for ambulatory monitoring involved in preliminary diagnostic indicators of cardiac diseases or stroke. The growing number of recent developments in wearable devices is reflective of the increasing demand in wrist-worn activity trackers for fitness and health applications. Indeed, the wrist represents a convenient location in terms of form factor and acceptability for patients. While most commercially-available devices are based on optical methods for heart rate measurement, others methods were also developed, based on various physiological phenomena. This review is focused on heart rate measurement methods located on forearm and more specifically on the wrist. For each method, the physiological mechanism involved is described, and the associated transducers for bio-signal acquisition as well as practical developments and prototypes are presented. Methods are discussed on their advantages, limitations and their suitability for an ambulatory use. More specifically, the superposition of motion artefacts over the signal of interest is one of the largest drawbacks for these methods, when used out of laboratory conditions. As such, artefact reduction techniques proposed in the literature are also presented and discussed.
21 citations
Cites methods from "A novel sensor for wrist based opti..."
...Performance of yellow-orange PPG system was evaluated over different skins tone by [23], in terms of Perfusion Index (PI) which represents the ratio of AC to DC components....
[...]
TL;DR: This study indicates that it is realistic today to develop a PPG sensor able to be integrated into an ear tag for mid-sized and larger farm animals for continuously and accurately monitoring their HRs.
Abstract: For all homoeothermic living organisms, heart rate (HR) is a core variable to control the metabolic energy production in the body, which is crucial to realize essential bodily functions. Consequently, HR monitoring is becoming increasingly important in research of farm animals, not only for production efficiency, but also for animal welfare. Real-time HR monitoring for humans has become feasible though there are still shortcomings for continuously accurate measuring. This paper is an effort to estimate whether it is realistic to get a continuous HR sensor for livestock that can be used for long term monitoring. The review provides the reported techniques to monitor HR of living organisms by emphasizing their principles, advantages, and drawbacks. Various properties and capabilities of these techniques are compared to check the potential to transfer the mostly adequate sensor technology of humans to livestock in term of application. Based upon this review, we conclude that the photoplethysmographic (PPG) technique seems feasible for implementation in livestock. Therefore, we present the contributions to overcome challenges to evolve to better solutions. Our study indicates that it is realistic today to develop a PPG sensor able to be integrated into an ear tag for mid-sized and larger farm animals for continuously and accurately monitoring their HRs.
20 citations
Cites background from "A novel sensor for wrist based opti..."
...A longer wavelength yellow-orange light showed consistent improvement in the signal quality of PPG acquired from varied skin tone subjects [154]....
[...]
01 Jan 2021
TL;DR: The review of the state-of-the-art of upper-limb wearable technologies involving wearable design, sensor technologies, wearable computing algorithms and wearable applications is presented along with a summary of their advantages and disadvantages.
Abstract: Wearable sensing devices, which are smart electronic devices that can be worn on the body as implants or accessories, have attracted much research interest in recent years. They are rapidly advancing in terms of technology, functionality, size, and real-time applications along with the fast development of manufacturing technologies and sensor technologies. By covering some of the most important technologies and algorithms of wearable devices, this paper is intended to provide an overview of upper-limb wearable device research and to explore future research trends. The review of the state-of-the-art of upper-limb wearable technologies involving wearable design, sensor technologies, wearable computing algorithms and wearable applications is presented along with a summary of their advantages and disadvantages. Toward the end of this paper, we highlight areas of future research potential. It is our goal that this review will guide future researchers to develop better wearable sensing devices for upper limbs.
16 citations
TL;DR: A yellow–orange wavelength-based optical scheme is incorporated into a wearable device for HRV estimation from dorsal side of the wrist, enabling stationary and ambulatory monitoring of HRV.
Abstract: Heart rate variability (HRV) is one of the important biomarkers of physical and psychological well-being. Hence, a convenient and minimally intrusive method for HRV measurement is advantageous. Although high levels of surrogacy of short-term HRV estimates obtained from the measurements of blood volume changes to traditional electrocardiographic (ECG) measurements have been reported, no detailed account on extraction of such parameters from a wrist-based optical monitor is found in the literature. In this paper, a yellow–orange wavelength-based optical scheme is incorporated into a wearable device for HRV estimation from dorsal side of the wrist. This design is pivotal in catering to a wider span of population with varied skin tones. The developed wearable in alliance with a gateway device is capable of picking up photoplethysmography from the measurement site, allowing estimation of HRV-indices within a confidence of 5% from ECG-derived parameters. The HRV measurement ecosystem is validated under the setting of three postural loads for 20 subjects, generating 60 data sets. Study results show statistically significant positive correlation and nonsignificant bias in Bland–Altman analysis, for the HRV-indices derived from either method. In most of the extracted HRV features, the observations in supine position showed minimum deviation from the reference. Estimation of short-term HRV-indices from wrist-based photoplethysmography under stationary conditions shows promising results from the study. Electrical and biological noninterference and ease of usage of the proposed design simplify stationary and ambulatory monitoring of HRV.
11 citations
Cites background or methods or result from "A novel sensor for wrist based opti..."
...A study had been conducted on 19 subjects with varied skin tones, in the previous work of the authors and escalated performance of the yellow–orange optical scheme over its counterpart is reported [29]....
[...]
...A study on the response of 590-nm wavelength as compared with the traditional choice of green (500–540 nm) wavelength on varied skin-tone subjects is presented, and affirmative results on the relative insensitivity of 590-nm optical scheme to melanin are reported in the previous work of the authors [29]....
[...]
...In the previous design using a wired prototype presented in [29], an H-bridge configuration for LED driver circuit was used....
[...]
...The signal quality metrics (SQMs) used in [29], signal to noise ratio (SNR), perfusion index (PI), and pulsatile strength...
[...]
...A yellow–orange (590 nm) wavelength optical sensor topology is used, which is relatively insensitive to skin pigmentation levels [29]....
[...]
01 Dec 2018
TL;DR: A solution that monitors the rates of heartbeats and respiration simultaneously by using a Frequency Modulated Continuous Wave radar with multiple antennas that employs multiple antennas and superposition to reduce the interference noises from unwanted motions in the background and any detection defects.
Abstract: Smart health calls for novel approaches to detect vital signs in non- contact, non-invasive and non-intrusive matters. In this work, we design a solution that monitors the rates of heartbeats and respiration simultaneously by using a Frequency Modulated Continuous Wave (FMCW) radar with multiple antennas. This solution measures the reflections from heartbeats and respiration at a high frequency of 4 K H z to capture fine dynamics of motions with big data. It employs multiple antennas and superposition to reduce the interference noises from unwanted motions in the background and any detection defects. The heart and respiration rates are detected in the frequency domains after a chain of preprocessing techniques on the sensed big data. With extensive experiments in a lab office, this system demonstrates high accuracies in various cases: 98% in the still case, 95% with finger motions and 96% with body motions. The tests also confirm that multiple antennas and signal superposition improve the detection accuracy and reliability.
9 citations
Cites background from "A novel sensor for wrist based opti..."
...The oximeter measures heart rates by sensing the light abortion degree from shining the light into the skin [17]....
[...]
References
More filters
TL;DR: Photoplethysmography is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue and is often used non-invasively to make measurements at the skin surface.
Abstract: Photoplethysmography (PPG) is a simple and low-cost optical technique that can be used to detect blood volume changes in the microvascular bed of tissue. It is often used non-invasively to make measurements at the skin surface. The PPG waveform comprises a pulsatile ('AC') physiological waveform attributed to cardiac synchronous changes in the blood volume with each heart beat, and is superimposed on a slowly varying ('DC') baseline with various lower frequency components attributed to respiration, sympathetic nervous system activity and thermoregulation. Although the origins of the components of the PPG signal are not fully understood, it is generally accepted that they can provide valuable information about the cardiovascular system. There has been a resurgence of interest in the technique in recent years, driven by the demand for low cost, simple and portable technology for the primary care and community based clinical settings, the wide availability of low cost and small semiconductor components, and the advancement of computer-based pulse wave analysis techniques. The PPG technology has been used in a wide range of commercially available medical devices for measuring oxygen saturation, blood pressure and cardiac output, assessing autonomic function and also detecting peripheral vascular disease. The introductory sections of the topical review describe the basic principle of operation and interaction of light with tissue, early and recent history of PPG, instrumentation, measurement protocol, and pulse wave analysis. The review then focuses on the applications of PPG in clinical physiological measurements, including clinical physiological monitoring, vascular assessment and autonomic function.
2,836 citations
TL;DR: An integrated review of the transfer of optical radiation into human skin is presented, aimed at developing useful models for photomedicine.
2,499 citations
"A novel sensor for wrist based opti..." refers background in this paper
...Anderson and Parrish [8] examined the characteristics of skin and projected that the 978-1-5090-3596-0/17/$31.00 ©2017 IEEE melanin content in skin absorbs wavelength in the regions 350 - 1200 nm....
[...]
...Relation between melanin and HbO2 absorption coefficient and wavelength[8]....
[...]
...The factors that affect the quality of signal from the measurement site are largely determined by the optical properties of skin [8] as well as the sensor....
[...]
...Anderson and Parrish [8] examined the characteristics of skin and projected that the This full text paper was peer-reviewed at the direction of IEEE Instrumentation and Measurement Society prior to the acceptance and publication....
[...]
21 Feb 2007
704 citations
"A novel sensor for wrist based opti..." refers methods in this paper
...Photoplethysmography (PPG) is a technique to measure blood volume change and provides a direct indication of several cardiological parameters [3]....
[...]
06 Nov 2014
TL;DR: Evaluated accuracy of two PPG based HR monitors during exercise indicated that performance of devices depends on various parameters, including specified activity, sensor type and device placement.
Abstract: Wearable monitoring of heart rate (HR) during physical activity and exercising allows real time control of exercise intensity and training effect. Recently, technologies based on pulse plethysmography (PPG) have become available for personal health management for consumers. However, the accuracy of these monitors is poorly known which limits their application. In this study, we evaluated accuracy of two PPG based (wrist i.e. Mio Alpha vs forearm i.e. Schosche Rhythm) commercially available HR monitors during exercise. 21 healthy volunteers (15 male and 6 female) completed an exercise protocol which included sitting, lying, walking, running, cycling, and some daily activities involving hand movements. HR estimation was compared against values from the reference electrocardiogram (ECG) signal. The heart rate estimation reliability scores for <;5% accuracy against reference were following: mio Alpha 77,83% and Scosche Rhytm 76,29%. The estimated results indicate that performance of devices depends on various parameters, including specified activity, sensor type and device placement.
133 citations
"A novel sensor for wrist based opti..." refers background in this paper
...It has been found that sensor characteristics and placement play a crucial role in picking up optimum signal quality from the dorsal side of the wrist where the wearable is usually preferred to be worn, since its form factor resembles that of a watch [5]....
[...]
Book•
01 Jan 2014
TL;DR: This book provides the first comprehensive resource of all currently used wearable devices in an accessible and structured manner and helps engineers manufacture wearable devices with information on current technologies, with a focus on end user needs and recycling requirements.
Abstract: Written by industry experts, this book aims to provide you with an understanding of how to design and work with wearable sensors. Together these insights provide the first single source of information on wearable sensors that would be a valuable addition to the library of any engineer interested in this field. Wearable Sensors covers a wide variety of topics associated with the development and application of various wearable sensors. It also provides an overview and coherent summary of many aspects of current wearable sensor technology. Both industry professionals and academic researchers will benefit from this comprehensive reference which contains the most up-to-date information on the advancement of lightweight hardware, energy harvesting, signal processing, and wireless communications and networks. Practical problems with smart fabrics, biomonitoring and health informatics are all addressed, plus end user centric design, ethical and safety issues. * Provides the first comprehensive resource of all currently used wearable devices in an accessible and structured manner.* Helps engineers manufacture wearable devices with information on current technologies, with a focus on end user needs and recycling requirements.* Combines the expertise of professionals and academics in one practical and applied source.
116 citations
"A novel sensor for wrist based opti..." refers background in this paper
...It is found that the signal quality for PPG signals from non-peripheral measurement sites is optimum for the green wavelength [9] and it is proven that green is superior to Infra-Red [6]....
[...]