Pulsation Interval Normalization for Sudden Condition Change Detection

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Solution Overview

Problem

Existing technologies fail to accurately detect changes in physical conditions using pulsation intervals, particularly in detecting sudden changes in physical conditions, such as sudden deteriorations, due to individual differences in heart rate variance and reliance on electrocardiogram measurements.

Innovation Solution

A physical condition detection device and method that constructs user-specific reference pulsation models, normalizes real-time pulsation interval features, and updates these models in real-time to accurately detect changes in physical conditions by using pulsation intervals from non-contact sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the median of the resting state heart rate is used as a reference value for correcting individual differences in pulsation interval, then the measurement load is kept low and data processing is simplified, but the accuracy of detecting sudden changes in physical condition deteriorates due to heart rate variance even in the same user

Engineering Contradiction:

Improvedata processing efficiencyVSAvoidaccuracy of detecting sudden changes in physical condition

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The system performs preliminary measurement of pulsation intervals during a resting state before actual detection begins. This preliminary data is used to construct user-specific reference models that account for individual heart rate characteristics and variance, enabling accurate baseline comparison for future sudden change detection without requiring continuous high-load monitoring

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The reference pulsation models are constructed dynamically based on each user's individual characteristics measured during resting state. The system adapts to each user's specific heart rate patterns and variance, creating personalized reference values rather than using fixed population-based medians. This dynamic adaptation maintains low measurement load while improving detection accuracy

Inventive Principle:

Principle #15Dynamics

2Measurement precision

If electrocardiogram information is used as input for detecting physical condition changes, then the accuracy of detection is improved, but the measurement load and data processing complexity increase significantly

Engineering Contradiction:

Improveaccuracy of physical condition detectionVSAvoidmeasurement and data processing complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The system extracts only the essential pulsation interval information from cardiac activity data, discarding the complex electrocardiogram waveform details. By focusing solely on the timing between heartbeats rather than the full ECG signal, the system achieves sufficient detection accuracy with significantly reduced data processing requirements and simpler device configuration

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of using complex electrocardiogram measurements, the system uses simplified pulsation interval data that copies only the essential temporal information needed for detection. This simplified representation maintains the ability to detect physical condition changes while eliminating the complexity of full ECG analysis

Inventive Principle:

Principle #26Copying

3Ease of operation

If a single median value of resting state heart rate is used as reference, then the system operation is simplified, but the ability to accurately grasp individual user's pulsation interval reference deteriorates

Engineering Contradiction:

Improvesystem operation simplicityVSAvoidaccuracy of individual user pulsation reference

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The system implements local quality by creating personalized reference models for each user based on their individual resting state measurements. Instead of applying a single global median value to all users, the system adapts the reference values to match each user's specific heart rate characteristics, ensuring accurate individualized detection while maintaining straightforward system operation

Inventive Principle:

Principle #3Local quality

Data Source

PatentUS20250366764A1Physical condition detection device, physical condition detection system, physical condition detection method, and storage medium storing physical condition detection program

Publication Date: 2025.12.04 MITSUBISHI ELECTRIC CORP

AI summary

A physical condition detection device determines a change in physical condition of a subject as an inspection target user, includes processing circuitry to construct a reference of a pulsation interval of each of users as a reference pulsation model in regard to each user, to select the reference pulsation model of the subject from the reference pulsation models and to generate a reference value indicating the pulsation interval of the subject from the selected reference pulsation model, to receive time-series pulsation information being information regarding the subject detected by a sensor, to extract a feature value of a real-time pulsation interval from the time-series pulsation information, and to correct the feature value by normalizing the feature value by using the reference value, thereby generating a real-time corrected feature value, and to determine a change in the physical condition of the subject based on the real-time corrected feature value.