Camera-Based SpO2 Monitoring Using Physiological Activity Images

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Solution Overview

Problem

Current contact-based SpO2 measurement devices are impractical for long-term monitoring due to discomfort and hygiene issues, and remote deep learning-based SpO2 measurement techniques are not yet at state-of-the-art for accurate and continuous health monitoring.

Innovation Solution

A system and method using a camera to capture color video frames, apply computer vision for face detection and landmark identification, generate a Physiological Activity Image (PAI) through image and signal processing, and utilize a deep learning model for SpO2 estimation, providing a contactless and accurate SpO2 measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If contact-based pulse oximeters are used for SpO2 measurement, then measurement accuracy is improved, but comfort and hygiene are worsened

Engineering Contradiction:
ImproveSpO2 measurement accuracyVSAvoidComfort and hygiene
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical contact-based pulse oximeter with a contactless camera system that uses image processing and deep learning to estimate SpO2. This substitution eliminates physical contact, thereby improving comfort and hygiene while maintaining measurement capability through computational analysis of facial images.

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

Solution Approach 2:

The patent introduces an intermediary processing pipeline between the camera and SpO2 estimation. This includes image processing modules that extract physiological signals from facial images, and deep learning models that translate these signals into SpO2 values. This intermediary system enables accurate measurement without direct contact.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of stationary object

If contact-based devices are used for long-term monitoring, then measurement continuity is improved, but comfort and usability are worsened

Engineering Contradiction:
ImproveMonitoring durationVSAvoidComfort and usability
Core Design Contradiction:
Duration of action of stationary objectVSEase of operation

Solution Approach 1:

By replacing the mechanical contact device with a contactless camera-based system, the patent enables long-term monitoring without the discomfort and hygiene issues that limit the duration of use of traditional pulse oximeters. The system can operate continuously as the camera simply captures images without physical contact.

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

3Reliability

If contact-based monitoring is used, then measurement reliability is improved, but spread of infectious diseases is facilitated

Engineering Contradiction:
ImproveMeasurement reliabilityVSAvoidSpread of infectious diseases
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent substitutes the contact-based measurement system with a contactless camera system that captures facial images and processes them to estimate SpO2. This eliminates the physical contact that could facilitate the spread of infectious diseases while maintaining measurement reliability through robust image processing and deep learning algorithms.

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

4Ease of operation

If remote deep learning-based SpO2 measurement is used, then comfort and hygiene are improved, but measurement accuracy is worsened

Engineering Contradiction:
ImproveComfort and hygieneVSAvoidSpO2 measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent introduces sophisticated intermediary processing steps between the camera and final SpO2 estimation. These include image processing modules that extract physiological signals from facial images, and deep learning models that accurately translate these signals into SpO2 values. This detailed intermediary processing ensures high accuracy despite the contactless approach.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent transforms the input data through multiple parameter changes and processing stages. Facial images are converted into physiological signals through image processing, and then these signals are transformed into SpO2 estimates through deep learning. This multi-stage parameter transformation enables accurate measurement while maintaining comfort and hygiene.

Inventive Principle:
Principle #35Parameter changes

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 a comfortable and hygienic method for continuous SpO2 monitoring, leveraging deep learning for enhanced accuracy and integration into telehealth, wellness programs, and clinical applications.

Implementation Method 1

executing light intensity analysis for the color image frames of the subject

Methodology Applied
Scientific EffectLight intensity analysis: Absorption (EM radiation)

Data Source

PatentUS20250268493A1System and method for camera-based remote blood oxygen saturation monitoring
Publication Date: 2025.08.28 THE HONG KONG UNIV OF SCI & TECH
  • US20250268493A1 patent drawing
  • US20250268493A1 patent drawing
  • US20250268493A1 patent drawing

AI summary

A system includes a camera, a color image and signal processing system, a physiological activity image processing system, a blood oxygen saturation estimator, and a report output module. The camera captures color image frames of a subject. The color image and signal processing system extracts physiological signals by analyzing light intensity, detecting and resizing facial images, interpolating facial landmarks, creating facial patches, selecting patches based on landmarks, and extracting signals from different color channels. The physiological activity image processing system generates a PAI embedding the subject's physiological information by forming 1D signals, concatenating filtered 1D signals into 2D images for each color channel, and combining the 2D images along a color channel dimension. The blood oxygen saturation estimator, using a deep learning model, receives the PAI to estimate the subject's blood oxygen saturation level. The report output module provides a readable report of the estimation.