Blood Volume Pulse Measurements Research Articles

Remote estimation of pulse wave features related to arterial stiffness and blood pressure using a camera

Recent technological advances in the field of sensors, signal processing and image processing favor the development of new techniques for vital parameters monitoring such as imaging photoplethysmography (iPPG). iPPG is a simple and noninvasive measurement technique. It has been employed to remotely estimate heart and respiratory rates, oxygen saturation and blood pressure through the measurement of blood volume pulse using a camera. In the recent decades, researchers used the morphology of contact photoplethysmographic (cPPG) signal for the assessment of arterial stiffness, blood pressure, arteriosclerosis, cardiac output, and vascular aging. We propose to study, in this article, the similarities between iPPG and cPPG waveform features that are associated to cardiovascular diseases. A fast camera and contact probes were respectively employed to record iPPG and cPPG signals. Their waveform features such as time, areas, amplitude and second derivative features were then extracted and analyzed. Results show a high correlation between the two measurement techniques. This research opens several perspectives in the remote assessment of blood pressure and arterial stiffness, and therefore for non-contact diagnosis of several cardiovascular diseases.

Impact of makeup on remote-PPG monitoring

Camera-based remote photoplethysmography (remote-PPG) enables contactless measurement of blood volume pulse from the human skin. Skin visibility is essential to remote-PPG as the camera needs to capture the light reflected from the skin that penetrates deep into skin tissues and carries blood pulsation information. The use of facial makeup may jeopardize this measurement by reducing the amount of light penetrating into and reflecting from the skin. In this paper, we conduct an empirical study to thoroughly investigate the impact of makeup on remote-PPG monitoring, in both the visible (RGB) and invisible (Near Infrared, NIR) lighting conditions. The experiment shows that makeup has negative influence on remote-PPG, which reduces the relative PPG strength (AC/DC) at different wavelengths and changes the normalized PPG signature across multiple wavelengths. It makes (i) the pulse-rate extraction more difficult in both the RGB and NIR, although NIR is less affected than RGB, and (ii) the blood oxygen saturation extraction in NIR impossible. To the best of our knowledge, this is the first work that systematically investigate the impact of makeup on camera-based remote-PPG monitoring.

Non-contact Measurement of Blood Volume Pulse Using 3 signals from CCD Camera

Non-contact Measurement of Blood Volume Pulse Using 3 signals from CCD Camera

Psychophysiological audience responses to war journalism and peace journalism

This article presents and discusses the results of an experiment in which television viewers were exposed to either a war journalism (WJ) or a peace journalism (PJ) version of two news stories, on Australian government policies towards asylum seekers and US-sponsored ‘peace talks’ between Israel and the Palestinians, respectively. Before and after viewing, they completed a cognitive questionnaire and two tests designed to disclose changes in their emotional state. During the viewing, they also underwent measurement of blood volume pulse, from which their heart rate variability (HRV) was calculated. HRV measures effects on the autonomic nervous system caused by changes in breathing patterns as subjects respond to stimuli with empathic concern. Since these patterns are regulated by the vagal nerve, HRV readings can therefore be interpreted as an indicator of vagal tone, which Porges et al. propose as an ‘autonomic correlate of emotion’. In this study, vagal tone decreased from baseline through both WJ stories, but showed a slightly smaller decrease during the PJ asylum story and then a significant increase during the PJ Israel–Palestine story. These readings correlated with questionnaire results showing greater hope and empathy among PJ viewers and increased anger and distress among WJ viewers, of the Israel–Palestine story.