top of page
Screenshot 2020-04-27 14.09.36.png
Screenshot 2020-04-27 14.11.50.png
Screenshot 2020-04-27 14.14.31.png

Frontiers in Psychology Q1: Transdermal Optical Imaging Reveal Basal Stress via Heart Rate Variability Analysis (Click here to see the full Pubmed paper).

Wei, Jing & Luo, Hong & Wu, Si Jia & Zheng, Paul & Fu, Genyue & Lee, Kang. (2018). Transdermal Optical Imaging Reveal Basal Stress via Heart Rate Variability Analysis: A Novel Methodology Comparable to Electrocardiography. Frontiers in Psychology. 9. 10.3389/fpsyg.2018.00098. The present study examined the validity of a novel physiological measurement technology called transdermal optical imaging (TOI) technology at assessing basal stress. This technology conveniently, contactlessly, and remotely measures facial blood flow changes using a conventional digital video camera. We compared data from TOI against the pulse data collected from the FDA approved BIOPAC system. One hundred thirty-six healthy adults participated in the study. We found that TOI measurements of heart rate and heart rate variability (HRV), which reflects basal stress, corresponded strongly to those obtained from BIOPAC. These findings indicate that TOI technology is a viable method to monitor heart rate and HRV not only accurately but also conveniently, contactlessly, and remotely. Further, measures of HRV obtained via TOI serves as a valid index of basal stress. Potential applications of this technology in psychological research and other fields are discussed.

Country Switzerland -
SIR Ranking of Switzerland 81 H Index
Subject Area and Category Psychology
Publisher Frontiers Media S.A.
Publication type Journals




Cardiology and Cardiovascular Medicine Q1: Smartphone-Based Blood Pressure Measurement Using Transdermal Optical Imaging Technology (Click here to see the research abstract)

Luo, Hong & Yang, Deye & Barszczyk, Andrew & Vempala, Naresh & Wei, Jing & Wu, Si Jia & Zheng, Paul & Fu, Genyue & Lee, Kang & Feng, Zhong-Ping. (2019). Smartphone-Based Blood Pressure Measurement Using Transdermal Optical Imaging Technology. Circulation: Cardiovascular Imaging. 12. 10.1161/CIRCIMAGING.119.008857. Background: 
Cuff-based blood pressure measurement lacks comfort and convenience. Here, we examined whether blood pressure can be determined in a contactless manner using a novel smartphone-based technology called transdermal optical imaging. This technology processes imperceptible facial blood flow changes from videos captured with a smartphone camera and uses advanced machine learning to determine blood pressure from the captured signal.

Country United States -
SIR Ranking of United States 83H Index
Subject Area and Category 
Cardiology and Cardiovascular Medicine
Medicine (miscellaneous)
Radiology, Nuclear Medicine and Imaging
Publisher Lippincott Williams & Wilkins Ltd.
Publication type Journals
ISSN19420080, 19419651

Nature - Scientific Reports Q1: Transdermal optical imaging revealed different spatiotemporal patterns of facial cardiovascular activities (Click here to download the paper).

Liu, Jiangang & Luo, Hong & Zheng, Paul & Wu, Si Jia & Lee, Kang. (2018). Transdermal optical imaging revealed different spatiotemporal patterns of facial cardiovascular activities. Scientific Reports. 8. 10.1038/s41598-018-28804-0. Human cardiovascular activities are important indicators of a variety of physiological and psychological activities in human neuroscience research. The present proof-of-concept study aimed to reveal the spatiotemporal patterns of cardiovascular activities from the dynamic changes in hemoglobin concentrations in the face. We first recorded the dynamics of facial transdermal blood flow using a digital video camera and the Electrocardiography (ECG) signals using an ECG system simultaneously. Then we decomposed the video imaging data extracted from different sub-regions of a face into independent components using group independent component analysis (group ICA). Finally, the ICA components that included cardiovascular activities were identified by correlating their magnitude spectrum to those obtained from the ECG. We found that cardiovascular activities were associated with five independent components reflecting different spatiotemporal dynamics of facial blood flow changes. The strongest strengths of these ICA components were observed in the bilateral forehead, the left chin, and the left cheek, respectively. Our findings suggest that the cardiovascular activities presented different dynamic properties within different facial sub-regions, respectively. More broadly, the present findings point to the potential of the transdermal optical imaging technology as a new neuroscience methodology to study human physiology and psychology, non invasively and remotely in a contactless manner.

Country United Kingdom - SIR Ranking of United Kingdom 149H Index
Subject Area and Category Multidisciplinary
PublisherNature Publishing Group
Publication type Journals


Deception detection system and method

Date: 2019-08-27 | Patent No.: US10390747B2

System and Method for Contactless Blood Pressure Determination
Date: 2019-08-13 | Patent No.: US 10,376,192 B2

System and Method for Camera-Based Heartrate Tracking
Date: 2018-11-06 | Patent No.: US 10,117,588 B2

System and Method for Detecting Subliminal Facial Responses in Response to Subliminal Stimuli
Date: 2019-07-23 | Patent No.: US 10,360,443 B2


bottom of page