A camera-based multispectral setup for remote vital signs assessment

Paul, Michael; Venema, Boudewijn; Blažek, Vladimír; Mühlsteff, Jens; Leonhardt, Steffen

doi:10.1007/978-981-10-5122-7_242

Cited by 3 publications

(6 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This measurement approach allows for contactless assessment of the tissue perfusion with the same spatial resolution as in the camera’s field of view (FOV) [24,28,62]. Thus, every pixel of the camera’s sensor array can be considered a discrete element of the PPG sensor, as the functional-imaging frame of the FOV assesses vital parameters by performing computation for predefined regions of interest (ROI) or each pixel separately [63,64].…”

Section: Contactless Neonatal Imaging Technologiesmentioning

confidence: 99%

Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond

AlZubaidi

Ethawi

Schmölzer

et al. 2018

MPs

View full text Add to dashboard Cite

The sick preterm infant monitoring is an intriguing job that medical staff in Neonatal Intensive Care Units (NICU) must deal with on a daily basis. As a standards monitoring procedure, preterm infants are monitored via sensors and electrodes that are firmly attached to their fragile and delicate skin and connected to processing monitors. However, an alternative exists in contactless imaging to record such physiological signals (we call it as Physio-Markers), detecting superficial changes and internal structures activities which can be used independently of, or aligned with, conventional monitors. Countless advantages can be gained from unobtrusive monitoring not limited to: (1) quick data generation; (2) decreasing physical and direct contact with skin, which reduces skin breakdown and minimizes risk of infection; and (3) reduction of electrodes and probes connected to clinical monitors and attached to the skin, which allows greater body surface-area for better care. This review is an attempt to build a solid ground for and to provide a clear perspective of the potential clinical applications of technologies inside NICUs that use contactless imaging modalities such as Visible Light Imaging (VLI), Near Infrared Spectroscopy (NIRS), and Infrared Thermography (IRT).

show abstract

Section: Contactless Neonatal Imaging Technologiesmentioning

confidence: 99%

Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond

AlZubaidi

Ethawi

Schmölzer

et al. 2018

MPs

View full text Add to dashboard Cite

show abstract

“…The cameras used for the measurements and the resulting feature map resolutions are provided in Table 4, while the measurements are described below. An overview of the camera setup is given in [39]. Due to the setup, the cameras have a different FOV and parallax is present between the cameras.…”

Section: Video Sequencesmentioning

confidence: 99%

Spatio-temporal and -spectral feature maps in photoplethysmography imaging and infrared thermography

et al. 2021

Self Cite

View full text Add to dashboard Cite

Background Only a small fraction of the information available is generally used in the majority of camera-based sensing approaches for vital sign monitoring. Dedicated skin pixels, for example, fall into this category while other regions are often disregarded early in the processing chain. Methods We look at a simple processing chain for imaging where a video stream is converted to several other streams to investigate whether other image regions should also be considered. These streams are generated by mapping spatio-temporal and -spectral features of video segments and, thus, compressing the information contained in several seconds of video and encoding these in a new image. Two typical scenarios are provided as examples to study the applicability of these maps: face videos in a laboratory setting and measurements of a baby in the neonatal intensive care unit. Each measurement consists of the synchronous recording of photoplethysmography imaging (PPGI) and infrared thermography (IRT). We report the results of a visual inspection of those maps, evaluate the root mean square (RMS) contrast of foreground and background regions, and use histogram intersections as a tool for similarity measurements. Results The maps allow us to distinguish visually between pulsatile foreground objects and an image background, which is found to be a noisy pattern. Distortions in the maps could be localized and the origin could be discovered. The IRT highlights subject contours for the heart frequency band, while silhouettes show strong signals in PPGI. Reflections and shadows were found to be sources of signals and distortions. We can testify advantages for the use of near-infrared light for PPGI. Furthermore, a difference in RMS contrast for pulsatile and non-pulsatile regions could be demonstrated. Histogram intersections allowed us to differentiate between the background and foreground. Conclusions We introduced new maps for the two sensing modalities and presented an overview for three different wavelength ranges. The maps can be used as a tool for visualizing aspects of the dynamic information hidden in video streams without automation. We propose focusing on an indirect method to detect pulsatile regions by using the noisy background pattern characteristic, for example, based on the histogram approach introduced.

show abstract

“…Clinical studies involving several infants and assessing PR based on PPGI can be found in Vagedes et al (2004), Scalise et al (2012), Aarts et al (2013), Klaessens et al (2014), Mestha et al (2014), Villarroel et al (2014), Fernando et al (2015, Blanik et al (2016), Paul et al (2017), Antognoli et al (2018), Cobos-Torres et al (2018).…”

Section: Subjectsmentioning

confidence: 99%

“…Image resolutions were typically 640 × 480 px and below, while high-definition (HD) resolutions have been rare (e.g. Villarroel et al (2014), or Paul et al (2017) and Antognoli et al (2018)). In the past, charge-coupled device sensors were used, but nowadays, complementary metal-oxide-semiconductor (CMOS) sensors are prevalent.…”

Section: Camerasmentioning

confidence: 99%

See 1 more Smart Citation

Non-contact sensing of neonatal pulse rate using camera-based imaging: a clinical feasibility study

et al. 2020

View full text Add to dashboard Cite

Objective: Neonates and infants are patients who would benefit from less invasive vital sign sensing, especially from fewer cables and the avoidance of adhesive electrodes. Photoplethysmography imaging (PPGI) has been studied for medical applications in recent years: it is possible to assess various vital signs remotely, non-invasively, and without contact by using video cameras and light. However, studies on infants and especially on neonates in clinical settings are still rare. Hence, we conducted a single-center study to assess heart activity by estimating the pulse rate (PR) of 19 neonates. Approach: Time series were generated from tracked regions of interest (ROIs) and PR was estimated via a joint time-frequency analysis using a short-time Fourier transform. Artifacts, for example, induced by movement, were detected and flagged by applying a signal quality index in the frequency domain. Main results: The feasibility of PR estimation was demonstrated using visible light and near-infrared light at 850 nm and 940 nm, respectively: the estimated PR was as close as 3 heartbeats per minute in artifact-free time segments. Furthermore, an improvement could be shown when selecting the best performing ROI compared to the ROI containing the whole body. The main challenges are artifacts from motion, light sources, medical devices, and the detection and tracking of suitable regions for signal retrieval. Nonetheless, the PR extracted was found to be comparable to the contact-based photoplethysmography reference and is, therefore, a viable replacement if robust signal retrieval is ensured. Significance: Neonates are seldom measured by PPGI and studies reporting measurements on darker skin tones are rare. In this work, not only a single camera was used, but a synchronized camera setup using multiple wavelengths. Various ROIs were used for signal extraction to examine the capabilities of PPGI. In addition, qualitative observations regarding camera parameters and noise sources were reported and discussed.

show abstract

A camera-based multispectral setup for remote vital signs assessment

Cited by 3 publications

References 10 publications

Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond

Review of Biomedical Applications of Contactless Imaging of Neonates Using Infrared Thermography and Beyond

Spatio-temporal and -spectral feature maps in photoplethysmography imaging and infrared thermography

Non-contact sensing of neonatal pulse rate using camera-based imaging: a clinical feasibility study

Contact Info

Product

Resources

About