Respiration Rate Determination via Phase Removal from Triaxial Acceleration

Solution Overview

Problem

Existing respiration rate determining apparatuses using triaxial acceleration sensors face challenges in accurately measuring respiration rates due to variations in user posture, leading to false detection and instability in measurements.

Innovation Solution

A respiration rate determining apparatus that includes an obtaining unit for measuring accelerations in different directions, transform units for converting these accelerations into spectrum information in the frequency domain, phase removing units to extract amplitude spectra, a peak detector to identify the peak frequency, and a respiration rate calculator to calculate the respiration rate, which stabilizes the measurement by removing phase information and detecting respiratory components regardless of user posture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If triaxial acceleration sensor is used to measure respiration rate, then measurement coverage is improved, but measurement precision deteriorates due to phase differences caused by user posture

Engineering Contradiction:

Improvemeasurement coverageVSAvoidrespiration rate accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent extracts only the amplitude information from the spectrum information items by removing phase information. This is achieved through the phase removing unit which transforms spectrum information items into amplitude spectra, eliminating the harmful phase differences caused by user posture while preserving the useful amplitude data for respiration rate determination.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of trying to preserve phase information to maintain measurement accuracy, the patent inverts the approach by deliberately removing phase information. The phase removing unit eliminates phase data that causes measurement errors due to posture variations, while the amplitude spectra still contain sufficient information for accurate respiration rate determination.

Inventive Principle:

Principle #13The other way round (Inversion)

2Difficulty of detecting and measuring

If acceleration sensor is attached to chest to detect chest movement, then respiration detection capability is improved, but reliability deteriorates due to false detection from posture variations

Engineering Contradiction:

Improverespiration detection capabilityVSAvoidmeasurement stability

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent extracts only the amplitude information from the spectrum information items by removing phase information. This is achieved through the phase removing unit which transforms spectrum information items into amplitude spectra, eliminating the harmful phase differences caused by user posture while preserving the useful amplitude data for respiration rate determination.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary processing step between acceleration measurement and respiration rate calculation. The phase removing unit acts as an intermediary that filters out the harmful phase information while preserving the useful amplitude information, thereby mediating between the raw sensor data and the final respiration rate determination to improve reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of information

If phase information is retained in spectrum analysis, then information completeness is improved, but measurement accuracy deteriorates due to phase differences from posture changes

Engineering Contradiction:

Improveinformation completenessVSAvoidrespiration rate accuracy

Core Design Contradiction:

Loss of informationVSMeasurement precision

Solution Approach 1:

The patent extracts only the amplitude information from the spectrum information items by removing phase information. This is achieved through the phase removing unit which transforms spectrum information items into amplitude spectra, eliminating the harmful phase differences caused by user posture while preserving the useful amplitude data for respiration rate determination.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS10602961B2Respiration rate determining apparatus, respiration rate determining method, and program recording medium

Publication Date: 2020.03.31 PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD

AI summary

A respiration rate determining apparatus includes: an obtaining unit which obtains accelerations in directions that are mutually different, the accelerations being obtained by an acceleration sensor measuring a body movement by respiration of a user; a transform unit which transforms the accelerations in the directions obtained by the obtaining unit, into spectrum information items in a frequency domain; a phase removing unit which transforms the spectrum information items into amplitude spectra by removing phase information from the spectrum information items; a peak detector which adds up the amplitude spectra and detects a peak frequency based on an amplitude spectrum resulting from the adding up, the peak frequency indicating a respiratory component; and a respiration rate calculator which calculates a respiration rate using the peak frequency.