Handheld PPG Monitoring via Video Window Segmentation

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Solution Overview

Problem

Conventional methods for monitoring physiological parameters using photoplethysmography (PPG) are inaccurate due to external interference, require subjects to remain motionless, and involve bulky, non-portable equipment, leading to erroneous measurements and high costs.

Innovation Solution

A handheld device implements a method to capture and process video frames to determine consistent PPG waveforms, extracts relevant features, and uses a mathematical model based on ground truth values to accurately monitor physiological parameters like heart rate and blood oxygen levels in real-time, reducing computational resources and equipment size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional PPG techniques are used with video recording devices, then physiological parameters can be monitored, but measurement accuracy deteriorates due to external interference and subject movement

Engineering Contradiction:
Improvephysiological parameter measurement accuracyVSAvoidexternal interference and subject movement
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the video feed into multiple overlapping windows, each processed independently to extract PPG features. This segmentation allows the system to identify and discard windows affected by movement or interference, while combining results from clean windows to maintain measurement accuracy.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system implements feedback by analyzing the quality of each video window and providing feedback on whether the captured physiological data is reliable. The consistency analysis across multiple windows provides feedback to determine if measurements should be accepted or rejected, improving overall measurement accuracy.

Inventive Principle:
Principle #23Feedback

2Ease of operation

If conventional PPG equipment is used, then physiological monitoring is possible, but device portability deteriorates due to bulky equipment

Engineering Contradiction:
Improvedevice portabilityVSAvoidequipment size
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent makes conventional multi-functional video recording devices (smartphones, tablets, cameras) perform the additional function of physiological parameter monitoring through software processing. This eliminates the need for specialized bulky PPG equipment while maintaining monitoring capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces complex mechanical PPG sensing systems with optical video capture and computational image processing. By using standard camera hardware and software-based PPG extraction, the system achieves portability without sacrificing core functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If conventional PPG processing is used, then physiological parameters can be extracted, but computational resources and time increase

Engineering Contradiction:
Improveprocessing efficiencyVSAvoidcomputational time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent processes only a selected subset of video windows that meet quality criteria, rather than analyzing every frame or window. This partial processing approach reduces computational time while still capturing sufficient data for accurate physiological parameter extraction.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The system performs preliminary quality assessment of video windows before full PPG analysis. By pre-screening windows for motion artifacts and signal quality, the system avoids wasting computational resources on poor-quality data, thereby improving overall processing efficiency.

Inventive Principle:
Principle #10Preliminary action

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

The solution provides accurate and portable monitoring of physiological parameters, reduces errors due to subject movement, and minimizes computational and temporal resources, enabling convenient and scalable monitoring on handheld devices.

Implementation Method 1

a video frames of a body part of a subject is captured using a camera

Methodology Applied
Scientific EffectLight reflection: Reflection

Implementation Method 2

PPG involves an optical methodology, which can be unobtrusive in certain cases, working on the basis of dynamics of blood volume changes in the vasculature under the skin

Methodology Applied
Scientific EffectPhotoplethysmography: Absorption (EM radiation)

Data Source

PatentEP2829223B1Monitoring physiological parameters
Publication Date: 2019.06.12 TATA CONSULTANCY SERVICES LTD
  • EP2829223B1 patent drawingFigure 1
  • EP2829223B1 patent drawingFigure 2
  • EP2829223B1 patent drawingFigure 3

AI summary

A method for monitoring physiological parameters associated with a subject using a hand held device (134) is described herein. In an implementation, the method includes obtaining a plurality of sample photoplethysmographic (PPG) features associated with a sample subject, from a video of a body part (136) of the sample subject. From among the plurality of sample PPG features, at least one relevant sample PPG feature associated with the physiological parameter, is selected based on a ground truth value of the physiological parameter for the subject. Further, based on the at least one relevant sample PPG feature and the ground truth value of the physiological parameter, a mathematical model indicative of a correlation between the relevant sample PPG feature and the physiological parameter, is determined. The mathematical model can be deployed for monitoring the physiological parameter in real time.