Cuffless Blood Pressure Measurement via Smartphone Camera and Strain Gauge
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Solution Overview
Problem
Current methods for blood pressure monitoring are invasive, require specialized training and equipment, or are not accessible for ubiquitous monitoring, leading to low detection and control rates of hypertension, especially in resource-limited settings.
Innovation Solution
A device and method utilizing a pressure-sensitive display screen integrated with a mobile device, which includes a strain gauge array and optical camera to measure blood pressure without a cuff, allowing for calibration-free and cuff-less blood pressure measurement using oscillometric principles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If catheterization is used to measure BP, then measurement precision is improved, but the method becomes invasive and complex
Solution Approach 1:
The patent replaces the mechanical strain gauge system with an optical measurement system using a camera to capture finger blood volume changes. This substitution eliminates the need for mechanical pressure sensors and cuff inflation/deflation mechanisms, achieving non-invasive BP measurement while maintaining measurement precision through optical detection of vascular pulsations.
Solution Approach 2:
The patent extracts the essential measurement function from the complex cuff-based oscillometric system. By using a simple camera to detect blood volume oscillations in the finger and processing these signals through algorithms, the invention isolates the core measurement capability without requiring the entire complex cuff apparatus, thereby reducing device complexity while preserving measurement accuracy.
2Measurement precision
If auscultation is used to measure BP, then measurement precision is improved, but specialized training and equipment are required
Solution Approach 1:
The patent implements self-service BP measurement by enabling users to perform measurements independently using their smartphones. The camera automatically captures blood volume oscillations, and built-in algorithms process the data to provide BP readings without requiring specialized training or equipment. Users simply need to place their finger on the camera, eliminating the need for medical professionals or specialized devices.
Solution Approach 2:
The patent creates a digital copy of the physical measurement process. Instead of using physical cuffs and stethoscopes, the system uses a camera to capture optical images of the finger, digitally processes these images to detect blood volume changes, and calculates BP values. This digital copying approach maintains measurement precision while dramatically improving ease of operation and accessibility.
3Extent of automation
If oscillometric cuffs are used, then automatic BP measurement is achieved, but ubiquitous monitoring capabilities are not provided
Solution Approach 1:
The patent achieves universality by integrating BP measurement capability into any smartphone with a camera and processing algorithm. This multi-functional approach allows the same device (smartphone) to perform various functions including communication, entertainment, and medical measurement. The system can be used by anyone with a smartphone, providing ubiquitous monitoring capabilities across diverse populations and settings without requiring specialized equipment.
Solution Approach 2:
The patent replaces the physical cuff-based oscillometric system with a digital optical copying system. The camera captures optical images of the finger, and algorithms process these digital copies to extract BP information. This digital approach eliminates the need for physical cuffs, making the measurement accessible anywhere a smartphone can be used, thereby achieving true ubiquitous monitoring capabilities.
4Ease of operation
If volume clamping with PPG sensor is used, then non-invasive automatic finger BP measurement is achieved, but the method is prohibitively expensive
Solution Approach 1:
The patent uses a disposable, low-cost smartphone camera instead of expensive, specialized PPG sensors. The camera, which is already present in most smartphones, serves as the detection device. This approach eliminates the need for costly specialized medical equipment while maintaining non-invasive automatic measurement capabilities. The system leverages existing inexpensive technology to achieve the same functional outcome.
Solution Approach 2:
The patent replaces expensive PPG sensors with a camera-based optical detection system. The camera captures images of the finger, and algorithms process these optical copies to detect blood volume oscillations. This copying approach uses readily available, low-cost camera technology instead of expensive specialized sensors, dramatically reducing device cost while maintaining ease of operation and measurement accuracy.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables easy, accurate, and on-the-go blood pressure monitoring, increasing accessibility and reducing the need for specialized equipment, thereby improving hypertension detection and management.
Implementation Method 1
a pressure sensor integrated with the display screen such that the display screen is a pressure-sensitive display screen
Implementation Method 2
measuring blood volume oscillations within at least one artery of the user's finger via a sensor of the mobile device
Data Source
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AI summary
Various systems, techniques, and embodiments are disclosed for implementing a blood- pressure measurement method that does not require specialized equipment (such as inflatable blood pressure cuffs). The measurement can be taken from arterial locations within a user's finger, via the standard equipment and features of many widely-available consumer mobile devices. Such devices can be programmed to accurately and easily guide a user to press her finger on the screen of a device at a precise location, so that an accurate measurement can be taken. For example, guidance visualizations on a screen (such as finger silhouettes and animations) can be employed on the same screen on which a user presses her finger. Pressure sensitivity and optical camera readings are then used to calculate blood pressure for the user.