Remote Photoplethysmography Heart Rate Variability Detection Using Signal to Noise Ratio Bandpass Filtering

2021 ◽  
Author(s):  
Lin He ◽  
Kazi Shafiul Alam ◽  
Jiachen Ma ◽  
Eric Burkholder ◽  
William Cheng Chung Chu ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Signal To Noise Ratio ◽  
Signal To Noise ◽  
Remote Photoplethysmography ◽  
Noise Ratio

44 Signal-to-Noise Ratio During Haemodynamic Optimisation of AV Delay is Improved more by Atrial Pacing than by Increasing Heart Rate

Heart ◽  
2015 ◽  
Vol 101 (Suppl 4) ◽  
pp. A25.2-A26
Author(s):  
Alexander Sharp ◽  
Afzal Sohaib ◽  
Keith Willson ◽  
Jamil Mayet ◽  
Alun Hughes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Signal To Noise Ratio ◽  
Atrial Pacing ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Av Delay

scholarly journals RapidHRV: an open-source toolbox for extracting heart rate and heart rate variability

2021 ◽  
Author(s):  
Peter Kirk ◽  
Sarah Garfinkel ◽  
Oliver Joe Robinson
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Pulse Oximetry ◽  
Open Source ◽  
Visual Inspection ◽  
Signal To Noise Ratio ◽  
Simulated Data ◽  
Signal To Noise ◽  
Python Package ◽  
Insight Into

Heart rate and its variability have enabled insight into a myriad of psychophysiological phenomena. There is now an influx of research attempting using these metrics within both laboratory settings (typically derived through electrocardiography or pulse oximetry) and ecologically-rich contexts (via wearable photoplethysmography, i.e. smartwatches). However, these signals can be prone to artifacts and a low signal to noise ratio, which traditionally are detected and removed through visual inspection. Here, we developed an open-source Python package, RapidHRV, dedicated to the preprocessing, analysis, and visualization of time-domain heart rate and heart rate variability. Each of these modules can be executed with one line of code and includes automated cleaning. In simulated data, RapidHRV demonstrated excellent recovery of heart rate across most levels of noise (>= 10dB) and moderate-to-excellent recovery of heart rate variability even at relatively low signal to noise ratios (>=20dB) and sampling rates (>=20Hz). Validation in real datasets shows good-to-excellent recovery of heart rate and heart rate variability in electrocardiography and pulse oximetry recordings. Validation in real photoplethysmography demonstrated RapidHRV estimations were sensitive to heart rate and its variability under low motion conditions, but estimates were less stable under higher movement settings.

scholarly journals LOW COST WIRELESS ECG PATCH USING ESP32

2020 ◽  
Vol 12 (1) ◽  
pp. 31-35
Author(s):  
Budi Sugandi ◽  
Muhammad Haikal Satria ◽  
Hamdani Arif ◽  
Nelmiawati Nelmiawati ◽  
Indra Hardian Mulyadi
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Signal To Noise Ratio ◽  
Low Cost ◽  
Low Energy ◽  
Signal To Noise ◽  
Common Mode ◽  
Bluetooth Low Energy ◽  
Common Mode Rejection Ratio ◽  
Rejection Ratio

Elektrokardiograf (ECG) yang bersifat wearable dan nirkabel telah banyak digunakan untuk monitoring jangka panjang karena alasan praktis. Selain Signal to Noise Ratio (SNR) yang tinggi, salah satu manfaat ECG dalam bentuk patch adalah fleksibilitasnya bagi pengguna dalam menempatkan elektroda. Sebagian besar ECG patch nirkabel komersial yang ada di pasaran hanya dapat menampilkan Heart Rate Variability (HRV) saja, tanpa kemampuan untuk menyediakan atau merekam gelombang EKG. Beberapa produk komersial menggunakan dua elektroda saja: Right Arm (RA) dan Left Arm (LA), tanpa elektroda tambahan yang disebut Right Arm Drive (RLD). Selain itu, menyediakan lebih dari satu opsi teknologi nirkabel untuk ECG patch merupakan keuntungan tambahan. Pada penelitian ini, kami membuat ECG patch nirkabel berbiaya rendah yang memiliki kemampuan untuk menyediakan bentuk gelombang EKG (Lead I) dan menghitung HRV secara otomatis. Selain RA dan LA, alat ini menggunakan elektroda RLD untuk meningkatkan Common Mode Rejection Ratio (CMRR). Untuk pemrosesan data, kami menggunakan ESP32, mikrokontroler 32-bit berdaya rendah yang dilengkapi dengan Bluetooth Classic (BT), Bluetooth Low Energy (BLE), dan Wifi dalam modul yang ringkas. Hasil tes menunjukkan bahwa ECG patch yang dibuat menghasilkan perhitungan HRV yang lebih akurat serta waktu transisi 2,7 kali lebih cepat dibandingkan dengan produk komersial yang kami jadikan referensi.

scholarly journals 176-68: Signal-to-noise ratio during haemodynamic optimization of AV delay is improved more by atrial pacing than by increasing heart rate

EP Europace ◽  
2016 ◽  
Vol 18 (suppl_1) ◽  
pp. i134-i134
Author(s):  
Alexander Sharp ◽  
Afzal Sohaib ◽  
Keith Willson ◽  
Jamil Mayet ◽  
Alun Hughes ◽  
...  
Keyword(s):  
Heart Rate ◽  
Signal To Noise Ratio ◽  
Atrial Pacing ◽  
Signal To Noise ◽  
Noise Ratio ◽  
Av Delay

scholarly journals Measurement Characteristics of Athlete Monitoring Tools in Professional Australian Football

2020 ◽  
Vol 15 (4) ◽  
pp. 457-463 ◽  
Author(s):  
Samuel Ryan ◽  
Emidio Pacecca ◽  
Jye Tebble ◽  
Joel Hocking ◽  
Thomas Kempton ◽  
...  
Keyword(s):  
Heart Rate ◽  
Signal To Noise Ratio ◽  
Heart Rate Recovery ◽  
Average Heart Rate ◽  
Measurement Sensitivity ◽  
Signal To Noise ◽  
Athlete Monitoring ◽  
Monitoring Tools ◽  
Australian Football ◽  
Noise Ratio

Purpose: To examine the measurement reliability and sensitivity of common athlete monitoring tools in professional Australian Football players. Methods: Test–retest reliability (noise) and weekly variation (signal) data were collected from 42 professional Australian footballers from 1 club during a competition season. Perceptual wellness was measured via questionnaires completed before main training sessions (48, 72, and 96 h postmatch), with players providing a rating (1–5 Likert scale) regarding their muscle soreness, sleep quality, fatigue level, stress, and motivation. Eccentric hamstring force and countermovement jumps were assessed via proprietary systems once per week. Heart rate recovery was assessed via a standard submaximal run test on a grass-covered field with players wearing a heart rate monitor. The heart rate recovery was calculated by subtracting average heart rate during final 10 seconds of rest from average heart rate during final 30 seconds of exercise. Typical test error was reported as coefficient of variation percentage (CV%) and intraclass coefficients. Sensitivity was calculated by dividing weekly CV% by test CV% to produce a signal to noise ratio. Results: All measures displayed acceptable sensitivity. Signal to noise ratio ranged from 1.3 to 11.1. Intraclass coefficients ranged from .30 to .97 for all measures. Conclusions: The heart rate recovery test, countermovement jump test, eccentric hamstring force test, and perceptual wellness all possess acceptable measurement sensitivity. Signal to noise ratio analysis is a novel method of assessing measurement characteristics of monitoring tools. These data can be used by coaches and scientists to identify meaningful changes in common measures of fitness and fatigue in professional Australian football.

Determination of the Best Emulsion for the Microscopy of Crystals

1981 ◽  
Vol 39 ◽  
pp. 32-33
Author(s):  
David A. Grano ◽  
Kenneth H. Downing
Keyword(s):  
Spatial Frequency ◽  
Information Transfer ◽  
Signal To Noise Ratio ◽  
Experimental Situation ◽  
Photographic Emulsion ◽  
Modulation Transfer ◽  
Signal To Noise ◽  
Frequency Space ◽  
Noise Ratio

The retrieval of high-resolution information from images of biological crystals depends, in part, on the use of the correct photographic emulsion. We have been investigating the information transfer properties of twelve emulsions with a view toward 1) characterizing the emulsions by a few, measurable quantities, and 2) identifying the “best” emulsion of those we have studied for use in any given experimental situation. Because our interests lie in the examination of crystalline specimens, we've chosen to evaluate an emulsion's signal-to-noise ratio (SNR) as a function of spatial frequency and use this as our critereon for determining the best emulsion.The signal-to-noise ratio in frequency space depends on several factors. First, the signal depends on the speed of the emulsion and its modulation transfer function (MTF). By procedures outlined in, MTF's have been found for all the emulsions tested and can be fit by an analytic expression 1/(1+(S/S0)2). Figure 1 shows the experimental data and fitted curve for an emulsion with a better than average MTF. A single parameter, the spatial frequency at which the transfer falls to 50% (S0), characterizes this curve.

Experiments in Bright-Field Imaging with Hollow-Cone Illumination

1981 ◽  
Vol 39 ◽  
pp. 226-227
Author(s):  
W. Kunath ◽  
K. Weiss ◽  
E. Zeitler
Keyword(s):  
Signal To Noise Ratio ◽  
Carbon Support ◽  
Electronic System ◽  
Optic Axis ◽  
Hollow Cone ◽  
Signal To Noise ◽  
Bright Field ◽  
Noise Ratio ◽  
Single Field ◽  
Field Imaging

Bright-field images taken with axial illumination show spurious high contrast patterns which obscure details smaller than 15 ° Hollow-cone illumination (HCI), however, reduces this disturbing granulation by statistical superposition and thus improves the signal-to-noise ratio. In this presentation we report on experiments aimed at selecting the proper amount of tilt and defocus for improvement of the signal-to-noise ratio by means of direct observation of the electron images on a TV monitor.Hollow-cone illumination is implemented in our microscope (single field condenser objective, Cs = .5 mm) by an electronic system which rotates the tilted beam about the optic axis. At low rates of revolution (one turn per second or so) a circular motion of the usual granulation in the image of a carbon support film can be observed on the TV monitor. The size of the granular structures and the radius of their orbits depend on both the conical tilt and defocus.

Information capacity and bandwidth limitations in the SEM

1989 ◽  
Vol 47 ◽  
pp. 84-85
Author(s):  
D. C. Joy ◽  
R. D. Bunn
Keyword(s):  
Signal To Noise Ratio ◽  
Critical Dimension ◽  
Information Capacity ◽  
Acquisition Time ◽  
Signal To Noise ◽  
Sem Image ◽  
Probe Size ◽  
Minimum Number ◽  
Noise Ratio ◽  
Signal Channel

The information available from an SEM image is limited both by the inherent signal to noise ratio that characterizes the image and as a result of the transformations that it may undergo as it is passed through the amplifying circuits of the instrument. In applications such as Critical Dimension Metrology it is necessary to be able to quantify these limitations in order to be able to assess the likely precision of any measurement made with the microscope.The information capacity of an SEM signal, defined as the minimum number of bits needed to encode the output signal, depends on the signal to noise ratio of the image - which in turn depends on the probe size and source brightness and acquisition time per pixel - and on the efficiency of the specimen in producing the signal that is being observed. A detailed analysis of the secondary electron case shows that the information capacity C (bits/pixel) of the SEM signal channel could be written as :

Speech Reception in the Presence of Classroom Noise

1979 ◽  
Vol 10 (4) ◽  
pp. 221-230 ◽  
Author(s):  
Veronica Smyth
Keyword(s):  
Signal To Noise Ratio ◽  
Learning Processes ◽  
Speech Discrimination ◽  
Signal To Noise ◽  
Speech Reception ◽  
Monosyllabic Words ◽  
Noise Ratio

Three hundred children from five to 12 years of age were required to discriminate simple, familiar, monosyllabic words under two conditions: 1) quiet, and 2) in the presence of background classroom noise. Of the sample, 45.3% made errors in speech discrimination in the presence of background classroom noise. The effect was most marked in children younger than seven years six months. The results are discussed considering the signal-to-noise ratio and the possible effects of unwanted classroom noise on learning processes.

Quantifying the Effects of Background Speech Babble on Preschool Children's Novel Word Learning in a Multisession Paradigm: A Preliminary Study

2020 ◽  
Vol 63 (1) ◽  
pp. 345-356
Author(s):  
Meital Avivi-Reich ◽  
Megan Y. Roberts ◽  
Tina M. Grieco-Calub
Keyword(s):  
Word Learning ◽  
Signal To Noise Ratio ◽  
Preschool Age ◽  
Exposure Condition ◽  
Signal To Noise ◽  
Verbal Recall ◽  
Referent Selection ◽  
Main Effect ◽  
Noise Ratio ◽  
Novel Word Learning

Purpose This study tested the effects of background speech babble on novel word learning in preschool children with a multisession paradigm. Method Eight 3-year-old children were exposed to a total of 8 novel word–object pairs across 2 story books presented digitally. Each story contained 4 novel consonant–vowel–consonant nonwords. Children were exposed to both stories, one in quiet and one in the presence of 4-talker babble presented at 0-dB signal-to-noise ratio. After each story, children's learning was tested with a referent selection task and a verbal recall (naming) task. Children were exposed to and tested on the novel word–object pairs on 5 separate days within a 2-week span. Results A significant main effect of session was found for both referent selection and verbal recall. There was also a significant main effect of exposure condition on referent selection performance, with more referents correctly selected for word–object pairs that were presented in quiet compared to pairs presented in speech babble. Finally, children's verbal recall of novel words was statistically better than baseline performance (i.e., 0%) on Sessions 3–5 for words exposed in quiet, but only on Session 5 for words exposed in speech babble. Conclusions These findings suggest that background speech babble at 0-dB signal-to-noise ratio disrupts novel word learning in preschool-age children. As a result, children may need more time and more exposures of a novel word before they can recognize or verbally recall it.

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