scholarly journals A Thermal Skin Model for Comparing Contact Skin Temperature Sensors and Assessing Measurement Errors

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4906
Author(s):  
Braid A. MacRae ◽  
Christina M. Spengler ◽  
Agnes Psikuta ◽  
René M. Rossi ◽  
Simon Annaheim
Keyword(s):  
Skin Temperature ◽  
Measurement Errors ◽  
Local Temperature ◽  
Experimental Session ◽  
Adult Males ◽  
Skin Model ◽  
Potential Measurement ◽  
Temperature Disturbance ◽  
Custom Made ◽  
Environment Temperature

To improve the measurement and subsequent use of human skin temperature (Tsk) data, there is a need for practical methods to compare Tsk sensors and to quantify and better understand measurement error. We sought to develop, evaluate, and utilize a skin model with skin-like thermal properties as a tool for benchtop Tsk sensor comparisons and assessments of local temperature disturbance and sensor bias over a range of surface temperatures. Inter-sensor comparisons performed on the model were compared to measurements performed in vivo, where 14 adult males completed an experimental session involving rest and cycling exercise. Three types of Tsk sensors (two of them commercially available and one custom made) were investigated. Skin-model-derived inter-sensor differences were similar (within ±0.4 °C) to the human trial when comparing the two commercial Tsk sensors, but not for the custom Tsk sensor. Using the skin model, all surface Tsk sensors caused a local temperature disturbance with the magnitude and direction dependent upon the sensor and attachment and linearly related to the surface-to-environment temperature gradient. Likewise, surface Tsk sensors also showed bias from both the underlying disturbed surface temperature and that same surface in its otherwise undisturbed state. This work supports the development and use of increasingly realistic benchtop skin models for practical Tsk sensor comparisons and for identifying potential measurement errors, both of which are important for future Tsk sensor design, characterization, correction, and end use.

scholarly journals A new comprehensive Eye-Tracking Test Battery concurrently evaluating the Pupil Labs Glasses and the EyeLink 1000

2019 ◽  
Author(s):  
Benedikt V. Ehinger ◽  
Katharina Groß ◽  
Inga Ibs ◽  
Peter König
Keyword(s):  
Eye Tracking ◽  
Smooth Pursuit ◽  
Gold Standard ◽  
Measurement Errors ◽  
Test Battery ◽  
Head Movements ◽  
Experimental Session ◽  
Common Source ◽  
Eye Tracker ◽  
Spatial Accuracy

ABSTRACTEye-tracking experiments rely heavily on good data quality of eye-trackers. Unfortunately, it is often that only the spatial accuracy and precision values are available from the manufacturers. These two values alone are not sufficient enough to serve as a benchmark for an eye-tracker: Eye-tracking quality deteriorates during an experimental session due to head movements, changing illumination or calibration decay. Additionally, different experimental paradigms require the analysis of different types of eye movements, for instance smooth pursuit movements, blinks or microsaccades, which themselves cannot readily be evaluated by using spatial accuracy or precision alone. To obtain a more comprehensive description of properties, we developed an extensive eye-tracking test battery. In 10 different tasks, we evaluated eye-tracking related measures such as: the decay of accuracy, fixation durations, pupil dilation, smooth pursuit movement, microsaccade detection, blink detection, or the influence of head motion. For some measures, true theoretical values exist. For others, a relative comparison to a gold standard eye-tracker is needed. Therefore, we collected our gaze data simultaneously from a gold standard remote EyeLink 1000 eye-tracker and compared it with the mobile Pupil Labs glasses.As expected, the average spatial accuracy of 0.57° for the EyeLink 1000 eye-tracker was better than the 0.82° for the Pupil Labs glasses (N=15). Furthermore, we detected less fixations and shorter saccade durations for the Pupil Labs glasses. Similarly, we found fewer microsaccades using the Pupil Labs glasses. The accuracy over time decayed only slightly for the EyeLink 1000, but strongly for the Pupil Labs glasses. Finally we observed that the measured pupil diameters differed between eye-trackers on the individual subject level but not the group level.To conclude, our eye-tracking test battery offers 10 tasks that allow us to benchmark the many parameters of interest in stereotypical eye-tracking situations, or addresses a common source of confounds in measurement errors (e.g. yaw and roll head movements).All recorded eye-tracking data (including Pupil Labs’ eye video files), the stimulus code for the test battery and the modular analysis pipeline are available (https://github.com/behinger/etcomp).BVE, KG, IIandPKconceived the experiment.IIandBVEcreated the experiment and recorded the gaze data.BVEandKGperformed the analysis.BVE, KGandPKreviewed the manuscript critically.

scholarly journals Contactless Monitoring of Microcirculation Reaction on Local Temperature Changes

2019 ◽  
Vol 9 (22) ◽  
pp. 4947 ◽  
Author(s):  
Volynsky ◽  
Margaryants ◽  
Mamontov ◽  
Kamshilin
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Polarized Light ◽  
Thermal Exposure ◽  
Thermal Impact ◽  
Vasomotor Response ◽  
Temperature Changes ◽  
Custom Made ◽  
Electrocardiogram Ecg ◽  
System Operating

Assessment of skin blood flow is an important clinical task which is required to study mechanisms of microcirculation regulation including thermoregulation. Contactless assessment of vasomotor reactivity in response to thermal exposure is currently not available. The aim of this study is to show the applicability of the imaging photoplethysmography (IPPG) method to measure quantitatively the vasomotor response to local thermal exposure. Seventeen healthy subjects aged 23 ± 7 years participated in the study. A warm transparent compress applied to subject’s forehead served as a thermal impact. A custom-made IPPG system operating at green polarized light was used to monitor the subject’s face continuously and simultaneously with skin temperature and electrocardiogram (ECG) recordings. We found that the thermal impact leads to an increase in the amplitude of blood pulsations (BPA) simultaneously with the skin temperature increase. However, a multiple increase in BPA remained after the compress was removed, whereas the skin temperature returned to the baseline. Moreover, the BPA increase and duration of the vasomotor response was associated with the degree of external heating. Therefore, the IPPG method allows us to quantify the parameters of capillary blood flow during local thermal exposure to the skin. This proposed technique of assessing the thermal reactivity of microcirculation can be applied for both clinical use and for biomedical research.

Analysis of heavy ion beam probe potential measurement errors in the Madison Symmetric Torus

2004 ◽  
Vol 75 (10) ◽  
pp. 3502-3504 ◽  
Author(s):  
X. Zhang ◽  
J. Lei ◽  
K. A. Connor ◽  
D. R. Demers ◽  
P. M. Schoch ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Ion Beam ◽  
Heavy Ion ◽  
Potential Measurement ◽  
Madison Symmetric Torus ◽  
Heavy Ion Beam ◽  
Heavy Ion Beam Probe ◽  
Probe Potential

Body Composition (% Fat) and Heat Stress of Well Conditioned Young Adult Males

1982 ◽  
Vol 26 (6) ◽  
pp. 561-564
Author(s):  
Michael W. Riley ◽  
David J. Cochran ◽  
Arthur J. Soundy
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Young Adult ◽  
Skin Temperature ◽  
Body Fat ◽  
Bicycle Ergometer ◽  
The Body ◽  
Lean Body Weight ◽  
Adult Males ◽  
Young Adult Males

The physiological responses of heart rate, oxygen consumption, sweat loss, rectal temperature and mean skin temperature were monitored as eight well-conditioned young adult males were exposed to effective temperatures of 70°F, 80°F and 90°F. The body fat contents of the subjects ranged from 11.3% to 34%. The subjects pedalled a 300 kilopond meters/minute load on a bicycle ergometer for 25 minutes. Results indicate that body fat or the percent of body fat squared have a statistically significant effect on the dependent variables of oxygen consumption/lean body weight, change in heart rate, core-skin temperature gradient, and oxygen consumption/maximum oxygen consumption.

scholarly journals A new comprehensive eye-tracking test battery concurrently evaluating the Pupil Labs glasses and the EyeLink 1000

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7086 ◽  
Author(s):  
Benedikt V. Ehinger ◽  
Katharina Groß ◽  
Inga Ibs ◽  
Peter König
Keyword(s):  
Eye Tracking ◽  
Smooth Pursuit ◽  
Measurement Errors ◽  
Test Battery ◽  
Head Movements ◽  
Experimental Session ◽  
Common Source ◽  
Eye Tracker ◽  
Spatial Accuracy ◽  
Individual Subject

Eye-tracking experiments rely heavily on good data quality of eye-trackers. Unfortunately, it is often the case that only the spatial accuracy and precision values are available from the manufacturers. These two values alone are not sufficient to serve as a benchmark for an eye-tracker: Eye-tracking quality deteriorates during an experimental session due to head movements, changing illumination or calibration decay. Additionally, different experimental paradigms require the analysis of different types of eye movements; for instance, smooth pursuit movements, blinks or microsaccades, which themselves cannot readily be evaluated by using spatial accuracy or precision alone. To obtain a more comprehensive description of properties, we developed an extensive eye-tracking test battery. In 10 different tasks, we evaluated eye-tracking related measures such as: the decay of accuracy, fixation durations, pupil dilation, smooth pursuit movement, microsaccade classification, blink classification, or the influence of head motion. For some measures, true theoretical values exist. For others, a relative comparison to a reference eye-tracker is needed. Therefore, we collected our gaze data simultaneously from a remote EyeLink 1000 eye-tracker as the reference and compared it with the mobile Pupil Labs glasses. As expected, the average spatial accuracy of 0.57° for the EyeLink 1000 eye-tracker was better than the 0.82° for the Pupil Labs glasses (N= 15). Furthermore, we classified less fixations and shorter saccade durations for the Pupil Labs glasses. Similarly, we found fewer microsaccades using the Pupil Labs glasses. The accuracy over time decayed only slightly for the EyeLink 1000, but strongly for the Pupil Labs glasses. Finally, we observed that the measured pupil diameters differed between eye-trackers on the individual subject level but not on the group level. To conclude, our eye-tracking test battery offers 10 tasks that allow us to benchmark the many parameters of interest in stereotypical eye-tracking situations and addresses a common source of confounds in measurement errors (e.g., yaw and roll head movements). All recorded eye-tracking data (including Pupil Labs’ eye videos), the stimulus code for the test battery, and the modular analysis pipeline are freely available (https://github.com/behinger/etcomp).

scholarly journals Experimentally friendly approach towards nonlocal correlations in multisetting N-partite Bell scenarios

Quantum ◽  
2021 ◽  
Vol 5 ◽  
pp. 430
Author(s):  
Artur Barasiński ◽  
Antonín Černoch ◽  
Wiesław Laskowski ◽  
Karel Lemr ◽  
Tamás Vértesi ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Reference Frames ◽  
Simple Procedure ◽  
Bell Inequalities ◽  
Point Of View ◽  
Local Realism ◽  
Theoretical Point ◽  
Potential Measurement ◽  
Complete Knowledge ◽  
Feasible Alternative

In this work, we study a recently proposed operational measure of nonlocality by Fonseca and Parisio [Phys. Rev. A 92, 030101(R) (2015)] which describes the probability of violation of local realism under randomly sampled observables, and the strength of such violation as described by resistance to white noise admixture. While our knowledge concerning these quantities is well established from a theoretical point of view, the experimental counterpart is a considerably harder task and very little has been done in this field. It is caused by the lack of complete knowledge about the facets of the local polytope required for the analysis. In this paper, we propose a simple procedure towards experimentally determining both quantities for N-qubit pure states, based on the incomplete set of tight Bell inequalities. We show that the imprecision arising from this approach is of similar magnitude as the potential measurement errors. We also show that even with both a randomly chosen N-qubit pure state and randomly chosen measurement bases, a violation of local realism can be detected experimentally almost 100% of the time. Among other applications, our work provides a feasible alternative for the witnessing of genuine multipartite entanglement without aligned reference frames.

Measurement errors in vision based displacement monitoring of masonry bridges

2019 ◽  
Author(s):  
Sinan Acikgoz ◽  
Matthew J. DeJong ◽  
Kenichi Soga
Keyword(s):  
Measurement Errors ◽  
Measurement Accuracy ◽  
Calibration Method ◽  
Textured Surfaces ◽  
Displacement Monitoring ◽  
Camera Model ◽  
Vanishing Points ◽  
Potential Measurement ◽  
Out Of Plane ◽  
The Impact

<p>Vision based displacement monitoring techniques are increasingly used to monitor dynamic displacements in operational bridges. These techniques are particularly well-suited to remotely monitor masonry bridges, which possess textured surfaces that enable effective tracking of sub-mm displacements simultaneously at many locations of the bridge. However, end users need to be aware of potential measurement errors which can impact their measurements. This paper discusses two sources of errors which are particularly relevant for monitoring displacements in masonry bridges with the 2D DIC technique: scaling errors and out of plane movement induced errors. The former category of errors occur due to incorrect scaling of tracking results in pixel units to displacements in metric units. In this paper, a new calibration method is proposed to minimise these errors. The method uses the naturally existing parallel lines in the masonry texture to identify two vanishing points in the image. These vanishing points and the known world coordinates of an identified feature in the image are then used to determine the relative rotation of the image and object planes and the correct scaling factors for different displacement points. The second source of error relates to the limitation of 2D DIC to measure only planar displacements. When out of plane movements occur in the object plane, these are registered incorrectly as in-plane movements. Using a pinhole camera model, the impact of out of plane movements on measurement accuracy are quantified. The results provide insight into how out of plane errors may be minimised or removed in order to achieve a higher measurement accuracy. The findings are explained with the application of the aforementioned techniques to the monitoring of a masonry viaduct.</p>

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