Analysis of Gait Patterns by Using a Sound Sensor and Wireless Communication Miku Teruya Department...
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Transcript of Analysis of Gait Patterns by Using a Sound Sensor and Wireless Communication Miku Teruya Department...
Analysis of Gait Patterns by Using a Sound Sensor and Wireless Communication
Miku TeruyaDepartment of Information Communication, Okinawa National College of Technology,Okinawa, Japan
Content
Introduction Measurement Process of Gait Patterns Analysis of Sound and Vibration from
Footsteps Classification of Gait Pattern Wireless Measurements of Sounds Conclusion
Introduction
Gait pattern has so far been studied on strides and foot steps
Past analysis method
Aim of our research
Study on distinguishability of a person by classifying waveforms of sounds generated by foot steps
IssuesMotion Capture Foot Pressure
Expensive instruments High volume data processing Distinguishable for visible person only
Sounds Generated by Footsteps
Animals such as cats, dogs, and rabbits can distinguish its owner by hearing sounds generated by footsteps
We focused on analyzing waveforms of sounds generated by footsteps
We used ECM (Electret Condenser Microphone)as a sensor for measurements of sounds.
Configuration of Sound Sensor
Design of Transistor Amplifier
Design with variable gain for specific frequency by manually adjusting the circuit parameters during the measurements.
To ECM
R11
R13 R12R10
R2R8 To oscilloscope
Transistor Amplifier
Transistor Amplifier
Variable Resistors
Adjustment of Circuit Parameters for Optimization of Amplifier Gain
R11=1.5k[Ω]
6k[Ω]
R12=60[Ω]
0[Ω]
R13=0[Ω]
120[Ω]
R11=500~ 4.5k[Ω]
R13=0~120[Ω]
R12=0~120[Ω]
Adjustable R13 for over all gain
Frequency (Hz)
G
ain(
dB)
G
ain(
dB)
Frequency (Hz)
Frequency (Hz)
G
ain(
dB)
Adjustable R12 for gain at lower frequencyAdjustable R11 for SN optimization
500[Ω]120[Ω]
Measurements Process of Gait Patterns
Measurements Different Gait Patterns for
Stride: wide /small Scrape step, Toe landing, Heel landing
Measured for eleven different people
Sounds collector plate
Condensermicrophone
Transistoramplifier
Portable Oscilloscope
Computer
Measured data
Analyzed data
Analysis of Sounds and Vibration Analysis of measured waveforms; Classified with ①Wave Number, ②Wave Width,③Wave
Interval
①Wave number
②Wave width
③Wave interval
①Wave Number
②Wave Width[ms]
③Wave Interval[ms]
H 5 152.7 459.6J 3 338.5 360.4
Subject H Subject J
Comparison between two people of H and J
Time[ms]
Volta
ge[V
]
Volta
ge[V
]Time[ms]
②Wave width
①Wave number
③Wave interval
Analysis by Wave Number
Large Stride : Wave number is less than 4 Small Stride : Wave number is higher than 6※Red Circles shows each person
Stride: smallStride: LargeWave Number
Wave number : less than 4
Volta
ge[V
]
Volta
ge[V
]
Time[ms] Time[ms]
Wave number : higher than 6
Analysis by Wave Width and Interval
Heel landing : Wave width less than 230msToe landing : Wave width between 230 and 290ms Scrape steps : Wave width higher than 290ms & Wave interval less than 360ms
Wave Width Wave Interval
※Red circles show each person
Heel Landing Toe Landing Scrape Steps
Wave width:150~ 230msWave width: 230~290ms
Wave width: higher than 290ms
Wave Interval: less than 360ms
Step Speed
②Wave width ③Wave Interval
Wave width + Wave interval = One Step[s]
Numbers of steps per minute =60[s]/(Wave width + Wave interval)[s]
Low step speed : less than100[step/min.]High step speed : higher than 110[step/min.]
Step Speed
Time[ms]
Volta
ge[V
]
②Wave width +③Wave interval
※Red circles show each person
Verification of Repeatability
Subject B
Subject F
Wave forms were measured 4 times for two people of B and F
1st 2nd 3rd 4th
1st 2nd 3rd 4th
Comparison and Classification of Waveforms
Feature of waveforms measured for four people
Step speed [step/min]
Two Types of Sound Measurement Methods
Item Wired WirelessMeasurement Distance
Less than 3m Less than 1km
Sound Sensor Embedded in floor Attached to shoes
Equipment Simple configuration Complicated configuration
Floor Material Limited selection Easy to chooseType of Shoes Free selection Fixed Sound Mainly generated by
vibration of the floor
Mainly generated by mechanical shock of the shoes landing
Wireless Transmitter and Receiver
Receiver antenna
Shoes with ECM
Portable Oscilloscope
2.4GHzWireless receiver
2.4GHzWireless transmitter
Video capture
Amplifier circuit
Video Camera
Transmitter antenna
Computer for observation
Measurements of Waveforms with Wireless Communication
The sound signals were transmitted by 2.4GHz wireless transmitter
Sound voltage signals were generated at the ECM attached outside of the shoes
The signals were received by 2.4GHz wireless receiver
The sound data analysis were carried out by an Excel Macro Software
Waveforms from Right and Left Feet
Right foot
Left foot
Right footLeft foot
Ampl
itude
[V]
Transmitted by two channels of wireless frequencies
Comparison and Classification of Waveforms with Different Floor Materials
Right footLeft foot
Application of Gait Pattern Analysis
Investigation of Status of Human Body Detects the condition of health from the
state of the gait pattern. ⇒ Applicable to medical care and health.
Security System Applicable to security to admit
authorized personnel into protected house and building.
Sensor of Engine Sound Applicable to warning system for electric vehicles. Waveform generated by a vehicle
Conclusion We classified the waveforms with 4 factors of wave
width, wave interval, and step speed by analyzing the sound generated by foot steps.
We distinguished the gait patterns of eleven people by using the 4 factors.
We remotely measured sounds generated by a walking person in the distance by using 2.4GHz wireless communication. We classified the waveforms according to different floor materials.
Our analysis procedure would be useful for detecting the status of health and the security system.