Neural Network Heart Rate Detection via Facial Video PPG

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Solution Overview

Problem

Existing heart rate measurement technologies face challenges such as the risk of pathogen transmission, time-consuming clinic visits, and inaccurate readings in dynamic or poorly lit conditions, especially when using camera-based systems.

Innovation Solution

A neural network-based method that uses a camera to obtain a video clip of a subject's face, detects facial features, converts image color space to L*a*b*, and predicts a photoplethysmographic signal using a deep neural network, followed by Fourier transform analysis to determine heart rate, enabling remote and accurate measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional contact-based heart rate monitoring devices are used, then measurement can be obtained, but there is risk of pathogen transmission and requires clinic visits

Engineering Contradiction:
Improveheart rate measurementVSAvoidpathogen transmission risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses video imaging as an intermediary to capture heart rate information remotely. Instead of direct contact with the subject, the system captures video of the subject's face or body, extracts physiological signals through image processing, and determines heart rate without physical contact, thereby eliminating pathogen transmission risk while maintaining measurement reliability

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces mechanical contact-based sensing (such as pulse palpation or electrode contact) with optical-based video imaging. By substituting the mechanical measurement system with an optical system that captures blood flow-induced color changes in video frames, the system achieves contactless heart rate monitoring that eliminates the need for physical contact and associated infection risks

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

2Ease of operation

If camera-based heart rate measurement is used, then remote measurement is enabled, but accuracy deteriorates in challenging conditions such as head movement or poor lighting

Engineering Contradiction:
Improveremote measurement capabilityVSAvoidheart rate measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies dynamic image processing techniques that adapt to changing conditions. The system uses motion compensation algorithms to track and stabilize the region of interest despite head movements, and employs adaptive filtering to maintain signal quality under varying lighting conditions. This dynamic approach allows the system to maintain measurement precision while preserving the ease of remote operation

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent performs preliminary processing steps including video stabilization, region of interest extraction, and preliminary signal filtering before final heart rate calculation. By preparing and pre-processing the video data in advance, the system compensates for challenging conditions such as head movement and poor lighting, ensuring accurate measurements are achieved even in suboptimal environments

Inventive Principle:
Principle #10Preliminary action

3Measurement precision

If deep neural network processing is applied to video frames, then heart rate measurement accuracy is improved, but computational complexity and processing time increase

Engineering Contradiction:
Improveheart rate measurement accuracyVSAvoidneural network processing complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the deep neural network processing into distinct functional modules: video preprocessing, feature extraction networks, signal generation, and heart rate calculation. By dividing the complex processing task into smaller, specialized segments, the system achieves high measurement precision while making the overall system more manageable and efficient, allowing parallel processing and optimization of individual components

Inventive Principle:
Principle #1Segmentation

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

This approach allows for remote, accurate, and efficient heart rate measurement in various conditions, reducing the need for physical contact and improving accuracy by mitigating the effects of head movements and lighting variations.

Implementation Method 1

the deep neural network predicts a photoplethysmographic (PPG) signal based on the sequence of images

Methodology Applied
Scientific EffectPhotoplethysmography:

Implementation Method 2

applying a Fourier transform to the PPG signal to convert the PPG signal to the frequency domain

Methodology Applied
Scientific EffectFourier transform:

Data Source

PatentUS20240005505A1Neural network-based heart rate determinations
Publication Date: 2024.01.04 HEWLETT PACKARD DEVELOPMENT COMPANY LP
  • US20240005505A1 patent drawing
  • US20240005505A1 patent drawing
  • US20240005505A1 patent drawing

AI summary

In some examples, an electronic device comprises an interface to receive a video of a human face, a memory storing executable code, and a processor coupled to the interface and to the memory. As a result of executing the executable code, the processor is to receive the video from the interface, use a facial detection technique to produce a sequence of images of the human face based on the video, use a neural network to predict a photoplethysmographic (PPG) signal based on the sequence of images, convert the PPG signal to a frequency domain signal, and determine a heart rate by performing a frequency analysis on the frequency domain signal.