Bed Load Sensor Waveform Normalization for Heart Rate Accuracy

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Solution Overview

Problem

Existing biological information monitoring systems face challenges in accurately calculating biological information due to various error factors introduced by load detectors.

Innovation Solution

A biological information monitoring system that includes load detectors, a waveform calculation unit, and a biological information calculation unit. The system calculates waveforms based on detected load values and uses these waveforms to accurately determine respiration rates and heart rates, employing multiple calculation methods, including peak detection and normalization, to mitigate errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If load detectors are used to detect biological information, then the monitoring capability is provided, but measurement precision deteriorates due to error factors

Engineering Contradiction:
Improvemonitoring capabilityVSAvoidbiological information accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by transforming the raw load signal into a normalized waveform that removes amplitude variations. This normalization process changes the parameter representation from absolute load values to relative waveform patterns, thereby eliminating error factors related to loading conditions and improving measurement precision while maintaining monitoring capability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces an intermediary processing step between load detection and biological information calculation. The waveform calculation unit acts as an intermediary that processes the raw load signal through normalization and waveform transformation, separating the useful respiratory/heartbeat information from error factors before final calculation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If multiple calculation methods are employed, then measurement precision improves, but device complexity increases

Engineering Contradiction:
Improvebiological information accuracyVSAvoidcalculation system structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements dynamics by providing multiple calculation methods that can adaptively handle different waveform conditions. The system dynamically selects appropriate calculation approaches based on the characteristics of the normalized waveform, allowing high measurement precision across varying conditions while managing complexity through conditional logic rather than permanently complex architecture

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3957963B1Biological information monitoring system, bed system, and biological information monitoring method
Publication Date: 2025.06.04 MINEBEAMITSUMI INC
  • EP3957963B1 patent drawingFigure 1
  • EP3957963B1 patent drawingFigure 2~3
  • EP3957963B1 patent drawingFigure 4(a)~4(c)

AI summary

A biological information monitoring system (100) for monitoring the biological information of a subject (S) on a bed (BD), which comprises: one or more load detectors (11, 12, 13, 14) for detecting the load from the subject on the bed, said load detectors being provided below the bed or the bed legs; a waveform calculation unit (31) for calculating a waveform which shows temporal variation in the values detected by the load detectors depending on the subject's respirations or heartbeats; and a biological information calculation unit (32) for calculating the respiration rate or heart rate of the subject using the waveform. The biological information calculation unit comprises: a first calculation unit (321) for calculating the respiration rate or heart rate of the subject by a first means based on the waveform; a second calculation unit (322) for calculating the respiration rate or heart rate of the subject by a second means, said second means being different from the first means and comprising normalizing the waveform; and a calculation control unit (320) for, when the amplitude of the waveform is equal to or less than a threshold, then instructing the second calculation unit to execute the calculation of the respiration rate or heart rate.