Motion Detection Using Upper and Lower Body Sensor Fusion

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Solution Overview

Problem

Conventional motion detecting systems inaccurately detect standing up and sitting down motions due to similarities with other actions, such as picking up an object or looking, as they only consider upper body tilting.

Innovation Solution

A motion detecting system that utilizes both upper body and lower body sensor information to identify standing up and sitting down motions by extracting candidate sections from upper body sensor data and confirming cooperative movements with lower body sensor data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If motion detection is performed using only upper body tilting characteristics, then the detection method is simple, but the accuracy deteriorates due to false detection of similar motions

Engineering Contradiction:
Improvesimplicity of detection methodVSAvoidaccuracy of motion detection
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent divides the body into upper body and lower body segments, detecting motions separately in each segment and then integrating the results. The upper body sensor detects tilting characteristics while the lower body sensor detects leg movement characteristics, and the determination unit combines these segmented detections to identify standing-up and sitting-down motions accurately, resolving the contradiction between simple detection and accurate detection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent merges the detection results from upper body and lower body sensors by the determination unit. The upper body sensor information indicating tilting characteristics is combined with lower body sensor information indicating leg movement characteristics to make a comprehensive determination of standing-up and sitting-down motions, thereby improving accuracy while maintaining operational simplicity.

Inventive Principle:
Principle #5Merging (Combining)

2Device complexity

If only upper body sensor information is used for motion detection, then the device complexity is low, but the reliability deteriorates due to erroneous detection

Engineering Contradiction:
Improvecomplexity of sensor systemVSAvoidreliability of motion detection
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent segments the sensor system into upper body sensor and lower body sensor components, each detecting specific characteristics. The upper body sensor detects tilting while the lower body sensor detects leg movement, and the determination unit integrates these segmented detections to reliably identify standing-up and sitting-down motions, resolving the contradiction between device complexity and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The determination unit acts as an intermediary that processes and integrates information from both upper body and lower body sensors. It mediates between the simple sensor inputs and the reliable motion detection output, combining multiple sensor perspectives to eliminate erroneous detections while maintaining manageable system complexity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3586741B1Movement detection system, movement detection device, and movement detection method
Publication Date: 2023.04.12 FUJITSU LTD
  • EP3586741B1 patent drawingFigure 1
  • EP3586741B1 patent drawingFigure 2(A)~2(D)
  • EP3586741B1 patent drawingFigure 3

AI summary

Provided is a motion detecting system including: a section candidate extraction processing unit that extracts, as a candidate section, a section in which a standing-up motion or a sitting-down motion of a subject to be a target of motion detection is detected from first sensor information that indicates a motion of an upper body of the subject; and an identification unit that identifies, from second sensor information that indicates a motion of a lower body of the subject, a section in which the motion of the lower body cooperatively moved with the motion of the upper body is detected in the candidate section.