Transdermal optical imaging revealed different spatiotemporal patterns of facial cardiovascular activities

Remote pulse rate measurement from facial video has gained particular attention over the last few years. Research exhibits significant advancements and demonstrates that common video cameras correspond to reliable devices that can be employed to measure a large set of biomedical parameters without any contact with the subject. A new framework for measuring and mapping pulse rate from video is presented in this pilot study. The method, which relies on convolutional 3D networks, is fully automatic and does not require any special image preprocessing. In addition, the network ensures concurrent mapping by producing a prediction for each local group of pixels. A particular training procedure that employs only synthetic data is proposed. Preliminary results demonstrate that this convolutional 3D network can effectively extract pulse rate from video without the need for any processing of frames. The trained model was compared with other state-of-the-art methods on public data. Results exhibit significant agreement between estimated and ground-truth measurements: the root mean square error computed from pulse rate values assessed with the convolutional 3D network is equal to 8.64 bpm, which is superior to 10 bpm for the other state-of-the-art methods. The robustness of the method to natural motion and increases in performance correspond to the two main avenues that will be considered in future works.

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“…These areas contain significant PPG signal-to-noise ratios. The maps are somewhat similar to those presented in [82].…”

Section: Image Sequencesupporting

confidence: 81%

3D Convolutional Neural Networks for Remote Pulse Rate Measurement and Mapping from Facial Video

2019

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“…al. 27 , in which unique facial spatiotemporal patterns were observed, occasionally asymmetric, related to cardiovascular activity, and assumed to be related to the ANS activity, hence the relation to the emotional state.…”

Section: Discussionmentioning

confidence: 99%

Classification of emotional states via transdermal cardiovascular spatiotemporal facial patterns using multispectral face videos

Shvimmer

Simhon

Michael

et al. 2022

Sci Rep

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We describe a new method for remote emotional state assessment using multispectral face videos, and present our findings: unique transdermal, cardiovascular and spatiotemporal facial patterns associated with different emotional states. The method does not rely on stereotypical facial expressions but utilizes different wavelength sensitivities (visible spectrum, near-infrared, and long-wave infrared) to gauge correlates of autonomic nervous system activity spatially and temporally distributed across the human face (e.g., blood flow, hemoglobin concentration, and temperature). We conducted an experiment where 110 participants viewed 150 short emotion-eliciting videos and reported their emotional experience, while three cameras recorded facial videos with multiple wavelengths. Spatiotemporal multispectral features from the multispectral videos were used as inputs to a machine learning model that was able to classify participants’ emotional state (i.e., amusement, disgust, fear, sexual arousal, or no emotion) with satisfactory results (average ROC AUC score of 0.75), while providing feature importance analysis that allows the examination of facial occurrences per emotional state. We discuss findings concerning the different spatiotemporal patterns associated with different emotional states as well as the different advantages of the current method over existing approaches to emotion detection.

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“…Liu et al suggested that cardiovascular activities presented different dynamic properties within different facial sub-regions; moreover, blood vessels in the nasal region pass through a small space between the nasal bone and the skin. Furthermore, the nasal region has a higher concentration of blood vessels than other parts of the face [ 25 ].…”

Section: Discussionmentioning

confidence: 99%

The Use of Thermography as an Auxiliary Method for Monitoring Convalescence after Facelift Surgery: A Case Study

Chudecka

Dmytrzak²,

Leźnicka

et al. 2022

IJERPH

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Although IR thermography is widely used in medical diagnostics, there are no reports that describe the use of IR thermography in the evaluation of post-plastic-surgery regeneration processes. The aim of the study was to evaluate the potential of thermography as a method which, among others, allows us to determine the location and extent of the inflammatory process, supporting the clinical evaluation of the patient’s convalescence after a facelift surgery using the SMAS technique. During the study and in order to monitor the convalescence process, the patient had a series of face thermograms performed before surgery and up to the 6th week after it. The healing process after surgery was multidirectional for the contralateral areas of the face, leading to thermal asymmetry lasting up to the 3rd week of convalescence. The lowest Tmean values for ROIs were recorded in week 3 of the study and then they gradually increased, in week 6 after surgery, to the following values: chin = 33.1 ± 0.72 °C; cheek left = 33.0 ± 0.26 °C; cheek right = 33.2 ± 0.51 °C; ZFL = 33.8 ± 0.45 °C; ZFR = 33.6 ± 0.74 °C; ZLL = 32.6 ±0.55 °C; ZLR = 32.3 ± 0.32 °C. The temperatures of these areas were still lower than the baseline values obtained before surgery by 0.5–1.4 °C. The usefulness of thermography in the evaluation of post-operative convalescence in facial plastic surgery procedures shows potential in the context of diagnostic assessment of the dynamics of changes in the healing process.

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Transdermal optical imaging revealed different spatiotemporal patterns of facial cardiovascular activities

Cited by 26 publications

References 42 publications

3D Convolutional Neural Networks for Remote Pulse Rate Measurement and Mapping from Facial Video

3D Convolutional Neural Networks for Remote Pulse Rate Measurement and Mapping from Facial Video

Classification of emotional states via transdermal cardiovascular spatiotemporal facial patterns using multispectral face videos

The Use of Thermography as an Auxiliary Method for Monitoring Convalescence after Facelift Surgery: A Case Study

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