If you’re seasoned in the medical field, you’ve probably heard of photoplethysmography (PPG), which uses medical devices for vital sign monitoring. But have you heard of remote photoplethysmography (rPPG)?
In this new era of AI, rPPG is making waves in the healthcare space. It allows providers to remotely monitor the health and wellness of their patients with a single smartphone video. This breakthrough is positioned to revolutionize early detection and preventative care, but how does it work? Let’s review the ins and outs of rPPG.
What is rPPG?
To understand rPPG, it’s important first to understand PPG itself. PPG is a tool that measures parameters like heart rate (HR), respiratory rate (RR), blood pressure (BP), and more. To do so, PPG uses a physical sensor that combines a light source and a photodetector. When this sensor touches the body, the photodetector detects changes to the illuminated tissue. In doing so, PPG technology can collect many different physiologic measurements.
PPG is useful in both clinical and non-clinical settings. Healthcare providers can use it to monitor vital signs, identify health issues early, and promote healthier lifestyles in their patients. However, recent breakthroughs in AI and tech have allowed us to further advance the capabilities of PPG, specifically with the development of rPPG.
rPPG works similarly to PPG but uses a camera to collect data instead of physical contact with a sensor. With a simple video of your face from your smartphone, rPPG can analyze subtle changes to the skin’s color to create a remote PPG signal. This process allows rPPG to calculate an accurate pulse rate signal. As a result, rPPG is a useful and non-invasive alternative to traditional PPG.
Shen.AI is one company that has developed an AI health monitoring rPPG technology able to measure vitals with just a 60-second facial scan on a smartphone.
Principles of rPPG
Remote Photoplethysmography (rPPG) is a fascinating non-invasive optical technique that measures changes in blood volume and blood flow in the skin. The science behind rPPG lies in its ability to analyze light absorption by blood volume. When light is emitted onto the skin, some of it is absorbed by the blood, while the rest is reflected back. The amount of reflected light changes according to the blood volume, which is influenced by capillary dilation and constriction. By meticulously analyzing these changes in reflected light, rPPG can estimate vital signs such as heart rate, respiratory rate, and blood pressure. This innovative approach allows for a comprehensive understanding of one’s health without the need for physical contact.
How does rPPG work to detect blood volume changes?
So, how exactly can you get something like a blood pressure measurement from a video of your face? Well, it starts with a face scan.
Your smartphone camera “sees” your face, capturing a video that remote PPG can then analyze. Using face-scanning technology and artificial intelligence, we can detect color fluctuations within the skin that correspond to blood volume changes in the vessels. This technology can measure pulse and breathing rate accurately. This process is similar to how pulse oximeters work, but instead of direct contact with the skin, rPPG can measure these changes remotely.
Optimal conditions for accurate rPPG measurements
To ensure that rPPG measurements are as accurate as possible, certain conditions need to be met. Here are some key factors to consider:
- High-resolution camera with good video quality: A high-quality camera is essential for capturing the subtle changes in skin color that rPPG relies on.
- Stable and consistent lighting environment: Consistent lighting helps to minimize errors caused by shadows or varying light intensities.
- Subject stillness: The subject should remain as still as possible to avoid motion artifacts that can distort the measurements.
- Clear view of the subject’s face: Ensure that the face is free from obstructions like hair or glasses that could interfere with the analysis.
- Sufficient data collection period: Collecting data over a reasonable period helps to ensure that the measurements are reliable and accurate.
By adhering to these conditions, you can significantly enhance the accuracy and reliability of rPPG measurements.
rPPG in measuring vital signs for cardiovascular health monitoring
Using data on the changes in intensity and rhythm of skin color and blood volume, an rPPG signal can accurately estimate key health metrics like:
- Heart rate. How often your skin changes color will correlate to your heartbeat.
- Blood pressure. rPPG measures changes to blood flow and volume to calculate blood pressure.
- Respiratory rate. Blood movement can predict respiratory rate.
- And more. rPPG can measure other things like heart rate variability, cardiac stress, cardiac workload, breathing rate, and body mass index (BMI). With Shen.AI, you can get over 25 health metrics with just a one-minute face scan on a smartphone, including vital signs and health risks.
And to top it all off, none of these metrics require additional user input! But with some additional information, users can get full health checks to assess their cardiovascular disease risk factors.
With advancements in AI with rPPG, technology has the potential to promote early detection and preventative health, moving us towards healthier lives. Additionally, rPPG technology can be integrated into feature driver monitoring cameras to enhance driver safety by monitoring drowsiness and stress levels.
Validation studies
Numerous validation studies have been conducted to evaluate the accuracy of rPPG measurements. These studies have compared rPPG measurements with traditional methods of measuring vital signs, such as electrocardiography (ECG) and pulse oximetry. The results have been promising, showing that rPPG can provide accurate measurements of heart rate, respiratory rate, and blood pressure. High correlation coefficients and low error rates in these studies underscore the reliability of rPPG technology, making it a viable alternative to traditional methods for measuring vital signs.
Limitations and challenges
While rPPG technology holds great promise, it is not without its limitations and challenges. Some of the key issues include:
- Motion artifacts: Movement of the subject can introduce errors in rPPG measurements, making it crucial for the subject to remain still.
- Lighting variations: Changes in lighting conditions can affect the accuracy of rPPG measurements, necessitating a stable lighting environment.
- Skin tone and type: rPPG may not work as effectively on subjects with darker skin tones or certain skin conditions, posing a challenge for universal applicability.
- Clinical settings: rPPG may not be suitable for all clinical settings, such as in neonatal intensive care units, where precise and immediate measurements are critical.
Addressing these limitations and challenges will be essential for the widespread adoption and success of rPPG technology.
The role of rPPG as a non invasive optical technique in healthcare
Shen.AI empowers individuals to have accessible information through their everyday technology. rPPG does just that by integrating AI and health monitoring, allowing providers to get real-time data to improve patient care.
The benefits of rPPG are widespread, including its:
- Non-invasiveness. Unlike traditional PPG medical devices, no physical contact is required. Thus, rPPG can do things like measure heart rate remotely.
- Real-time insights. Providers get immediate results without the need for an office visit. rPPG can provide real-time data on pulse and breathing rate, which is crucial for continuous patient monitoring.
- Accessibility. Patients can use rPPG with just a smartphone, as the camera is low-cost and easy to obtain, making healthcare more accessible for all.
- Simplicity. There is no need for additional devices or information, making rPPG suitable for long-term continuous monitoring.
- Scalability. rPPG technologies are equipped to handle a growing number of users or monitoring sessions without a drop in performance, accuracy, or functionality.
- User-friendliness. rPPG is easy for providers and patients alike to use.
Additionally, Shen.AI offers further advantages via its Mention Multi Tonal Sensing Technology. This AI technology was developed by Shen.AI to promote total inclusivity for everyone. With this technology, we can provide reliable results to people of every skin tone and in a wide range of lighting conditions.
Unlike other companies, Shen.AI also doesn’t share data to the cloud or server. It does all calculations on your device, providing quick results while protecting your privacy.
Wrap up of rPPG applications
In summary, rPPG is the next AI-fueled breakthrough in healthcare. With a simple smartphone video, healthcare providers can gain key insights into their patients’ health and wellness. Noninvasive, simplistic, and accessible, rPPG technologies like Shen.AI are revolutionizing the future of early detection and preventative care.
Discover how Shen.AI leverages rPPG to revolutionize non-invasive health monitoring. Get your 1-minute health check with our demo.