Skin inhomogeneity as a source of error in remote PPG-imaging

Moço, Andreia; Stuijk, Sander; Haan, G Gerard de

doi:10.1364/boe.7.004718

Cited by 53 publications

(34 citation statements)

References 37 publications

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“…However, a non-contact camera-based system that operates from a distance records a significantly weaker blood volume waveform from any imaged skin region or internal tissue compared to a contact-based PulseOx. Therefore, prior [26][27][28][29] camera-only blood pulsation imaging system usually suffers from the challenge of significantly smaller signal-to-noise ratio. The small blood volume waveform, i.e., the signal of interest, rides on top of a much larger (approx.…”

mentioning

confidence: 99%

“…Moreover, the surface reflection can change drastically with even a slight movement of the skin, making the small blood perfusion-related signal recovery even more difficult in the presence of motion. As a result, recent attempts to obtain spatial maps of pulsatile blood perfusion using camera-only approaches have resulted in noisy and motion-corrupted perfusion estimates [26][27][28][29] with limited clinical value.…”

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confidence: 99%

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PulseCam: a camera-based, motion-robust and highly sensitive blood perfusion imaging modality

Kumar

Suliburk

Veeraraghavan

et al. 2020

Sci Rep

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Blood carries oxygen and nutrients to the trillions of cells in our body to sustain vital life processes. Lack of blood perfusion can cause irreversible cell damage. therefore, blood perfusion measurement has widespread clinical applications. in this paper, we develop pulsecam -a new camera-based, motionrobust, and highly sensitive blood perfusion imaging modality with 1 mm spatial resolution and 1 frame-per-second temporal resolution. Existing camera-only blood perfusion imaging modality suffers from two core challenges: (i) motion artifact, and (ii) small signal recovery in the presence of large surface reflection and measurement noise. PulseCam addresses these challenges by robustly combining the video recording from the camera with a pulse waveform measured using a conventional pulse oximeter to obtain reliable blood perfusion maps in the presence of motion artifacts and outliers in the video recordings. For video stabilization, we adopt a novel brightness-invariant optical flow algorithm that helps us reduce error in blood perfusion estimate below 10% in different motion scenarios compared to 20-30% error when using current approaches. PulseCam can detect subtle changes in blood perfusion below the skin with at least two times better sensitivity, three times better response time, and is significantly cheaper compared to infrared thermography. PulseCam can also detect venous or partial blood flow occlusion that is difficult to identify using existing modalities such as the perfusion index measured using a pulse oximeter. With the help of a pilot clinical study, we also demonstrate that pulsecam is robust and reliable in an operationally challenging surgery room setting. We anticipate that pulsecam will be used both at the bedside as well as a point-of-care blood perfusion imaging device to visualize and analyze blood perfusion in an easy-to-use and cost-effective manner. open Scientific RepoRtS | (2020) 10:4825 | https://doi.comparing pulsecam with an infrared thermal camera. To compare PulseCam and infrared thermography, we perform incremental vascular occlusion experiment on 9 participants (5 male and 4 female) of varying skin tones (Fitzpatrick Scale I to VI) and record their palm videos using both a color camera as well as Scientific RepoRtS | (2020) 10:4825 | https://doi.

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confidence: 99%

mentioning

confidence: 99%

PulseCam: a camera-based, motion-robust and highly sensitive blood perfusion imaging modality

Kumar

Suliburk

Veeraraghavan

et al. 2020

Sci Rep

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“…When lighting conditions are poor, a near-infrared camera system (Van Gastel, Stuijk & De Haan, 2015) could be used to overcome these conditions. Similarly, the presence of subjects of different skin phototypes and ages would affect SNR (De Haan & Jeanne, 2013; Moço, Stuijk & De Haan, 2016) due to the different extent of skin inhomogeneity and melanin concentrations. Finally, a bigger number of subjects would increase the inference validity.…”

Section: Discussionmentioning

confidence: 99%

Feasibility of assessing ultra-short-term pulse rate variability from video recordings

Finžgar

Podržaj

2020

PeerJ

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Objectives: Remote photoplethysmography (rPPG) is a promising non-contact measurement technique for assessing numerous physiological parameters: pulse rate, pulse rate variability (PRV), respiratory rate, pulse wave velocity, blood saturation, blood pressure, etc. To justify its use in ultra-short-term (UST) PRV analysis, which is of great benefit for several healthcare applications, the agreement between rPPGand PPG-derived UST-PRV metrics was studied. Approach: Three time-domain metrics-standard deviation of normal-to-normal (NN) intervals (SDNN), root mean square of successive NN interval differences (RMSSD), and the percentage of adjacent NN intervals that differ from each other by more than 50 ms (pNN50)-were extracted from 56 video recordings in a publicly available data set. The selected metrics were calculated on the basis of three groups of 10 s recordings and their average, two groups of 30 s recordings and their average, and a group of 60 s recordings taken from the full-length recordings and then compared with metrics derived from the corresponding reference (PPG) pulse waveform signals by using correlation and effect size parameters, and Bland-Altman plots.Main results: The results show there is stronger agreement as the recording length increases for SDNN and RMSSD, yet there is no significant change for pNN50. The agreement parameters reach r = 0.841 (p < 0.001), r = 0.529 (p < 0.001), and r = 0.657 (p < 0.001), estimated median bias −1.52, −2.28 ms and −1.95% and a small effect size for SDNN, RMSSD, and pNN50 derived from the 60 s recordings, respectively. Significance: Remote photoplethysmography-derived UST-PRV metrics manage to capture UST-PRV metrics derived from reference (PPG) recordings well. This feature is highly desirable in numerous applications for the assessment of one's health and well-being. In future research, the validity of rPPG-derived UST-PRV metrics compared to the gold standard electrocardiography recordings is to be assessed.

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“…The application of external pressure on the examined skin tissue, for example, might cause such variations. Previous cbPPG works show that the compression of superficial tissue leads to a significant change in the morphology and amplitude of the received signal [12,15]. Moço et al [15] argued that in this case, the cbPPG signal mostly arises from a deeper plexus due to the occlusion of superficial vessels.…”

Section: Color Allmentioning

confidence: 97%

“…Consequently, (i) the application of two filters with the same polarization direction at the camera and light source (parallel setting) allows the analysis of the skin surface, and (ii) the perpendicular alignment (perpendicular setting) allows the analysis of skin tissue beneath the surface [9]. Previous works in cbPPG applied the perpendicular setting to suppress specular reflectance from the skin surface [10][11][12][13][14][15][16][17][18]. However, investigations that systematically assess the benefit of polarization filtration for cbPPG are rare.…”

Section: Introductionmentioning

confidence: 99%

The value of polarization in camera-based photoplethysmography

Trumpp

Bauer

Rasche

et al. 2017

Biomed. Opt. Express

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Camera-based photoplethysmography (cbPPG) is a novel measuring technique that permits the remote acquisition of cardiovascular signals using video cameras. Research still lacks in fundamental studies to reach a deeper technical and physiological understanding. This work analyzes the employment of polarization filtration to (i) assess the gain for the signal quality and (ii) draw conclusions about the cbPPG signal's origin. We evaluated various forehead regions of 18 recordings with different color and filter settings. Our results prove that for an optimal illumination, the perpendicular filter setting provides a significant benefit. The outcome supports the theory that signals arise from blood volume changes. For lateral illumination, ballistocardiographic effects dominate the signal as polarization's impact vanishes.

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Skin inhomogeneity as a source of error in remote PPG-imaging

Cited by 53 publications

References 37 publications

PulseCam: a camera-based, motion-robust and highly sensitive blood perfusion imaging modality

PulseCam: a camera-based, motion-robust and highly sensitive blood perfusion imaging modality

Feasibility of assessing ultra-short-term pulse rate variability from video recordings

The value of polarization in camera-based photoplethysmography

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