Comparison and evaluation of the accuracy of accelerometers and gyroscopes for detecting gait PDF
Preview Comparison and evaluation of the accuracy of accelerometers and gyroscopes for detecting gait
M A S T E Comparison and evaluation of the accuracy of R accelerometers and gyroscopes for detecting gait events in a real life setting T H E S Wouter De Mol I S CAISR HalmstadUniversity,September7,2017 WouterDeMol:Comparisonandevaluationoftheaccuracyofaccelerome- tersandgyroscopesfordetectinggaiteventsinareallifesetting,©August 2017 ABSTRACT Gaitanalysisisthestudyofhumanlocomotion.Itisusedinavarietyof fieldssuchasthemedicalandsportssector.Thesedays,mostgaitanaly- sisisdoneingaitlaboratories.However,latelyonehasbeentryingtofind ways to complement these restricted, expensive environments by using inertial sensors such as gyroscopes and accelerometers. These sensors offer the possibility to collect more data and don’t limit the freedom of movementofthepeoplewhosegaitisbeinganalysed.Avarietyofalgo- rithmshavebeendevelopedtoextractgaiteventsfromthedatacollected bythesesensors.Thesealgorithmshavebeenvalidatedagainstsystems thatofferthegroundtruth,suchaspressuresensitiveinsoles,forceplates and visual motion capture systems. However, it remains unclear which typeofsensorismoresuitedfordetectinggaiteventsindifferentenviron- ments.Inthisthesisresearchisdonetoexaminehowbothtypeshandle different circumstances, positions and orientations. For the purpose of thisresearchdatawascollectedinanoutdoorsenvironment. iii Thisthesiswasmadepossiblethanksto: HalmstadUniversity&KULeuven Mysupervisors:SiddhartaKhandelwal&NicholasWickström Mypatientgirlfriend:Hanne Thefriendswhocametovisitme:Niels,Daphne&Tars MySwedishparkour-friend:Johannes Mysupportiveparents K1inKrüsbaret iv CONTENTS ListofFigures vi ListofTables x 1 introduction 1 2 state of the art 5 2.1 MEMScharacteristics 5 2.1.1 Temperaturesensitivity 6 2.1.2 Powerconsumption 8 2.2 Relatedwork 8 2.3 Sensorposition 9 2.4 Applicabilityforreal-timesituations 11 3 nature of angular velocity and linear acceler- ation gait signals 12 4 data collection 17 4.1 Calibration 17 4.2 Configuration 18 4.3 Collecteddata 18 4.4 Synchronizinginsoleswithshimmers 19 5 algorithms 23 5.1 AlgorithmsImplemented 24 5.1.1 Gyroscopealgorithm1:FRAC[14] 24 5.1.2 Gyroscopealgorithm2:CAT[38] 27 5.1.3 Gyroscopealgorithm3:JUNG[32] 29 5.1.4 Gyroscopealgorithm4:MAQ[35] 31 5.1.5 Gyroscopealgorithm5:GO[16] 31 5.1.6 Accelerometeralgorithm1:SK[28] 33 5.1.7 Accelerometeralgorithm2:TA[47] 34 5.1.8 Accelerometeralgorithm3:SELL[41] 34 5.1.9 Accelerometeralgorithm4:MAN[34] 35 6 results 37 6.1 Analysisoftheresultsgivenbythealgorithms 37 6.1.1 PWSresults 41 6.1.2 SWSresults 51 6.1.3 FWSresults 62 6.2 Discussionandcomparison(PWS&SWS&FWS) 72 6.2.1 Aretrospect 77 7 conclusion 78 7.1 Conclusion 78 7.2 Futureresearch 79 a appendix 80 a.1 Originalprotocoldatacollection 80 a.2 Statisticalanalysisdata 86 bibliography 101 v LIST OF FIGURES Figure1 Themainscheme 3 Figure2 Accelerationdataofeveryaxis 13 Figure3 Acceleration signals left shank during PWS in thefrequencydomain 13 Figure4 Angular velocity signal along the every axis of theshimmerplacedontheleftshankduringPWS 14 Figure5 Comparison of gyroscope data collected at the shankandthesacrum 14 Figure6 Gyroscopedatacollectedattherightwristdur- ingPWS 15 Figure7 Gyroscope data collected at the left ankle and shankduringPWS 15 Figure8 Closeupcomparisonofaccelerometerdatawith differentspeeds(Leftshank) 16 Figure9 Influenceoftheorientationonthegyroscopesig- nal 16 Figure10 Sum of the normal forces [N] detected by the insoles. 20 Figure11 Close-upofthesumoftheforcesdetectedbythe insoles 20 Figure12 Accelerationsignalshowsapeakatthemoment thepersonhitsthefloor 21 Figure13 Closeupofthedetectedeventsatthebeginning ofthetrial.Theangularvelocityisgivenindps. 22 Figure14 Closeupofthedetectedeventsattheendofthe trial.Theangularvelocityisgivenindps. 22 Figure15 Filtereddataversusoriginal 25 Figure16 Gaitcharacteristicpoints:Green:Midswing,Blue: IC,Red:FC,Yellow:TO.Theangularvelocityis givenindps. 28 Figure17 Indicationofthepeakangularaccelerationdur- ingPWSattheleftshank.Theangularvelocity isgivenindps. 30 Figure18 ResultsoftheoriginalimplementationofGouwanda’s algorithm.Theangularvelocityisgivenindps. 32 Figure19 Difference between TOs detected by both algo- rithmsduringPWS 37 Figure20 Difference between TOs detected by both algo- rithmsduringPWS.Theverticalaxisrepresents theamountofsamples. 37 Figure21 Closeupofthedetectedheelstrikesoftheright foot during PWS. The vertical axis represents theangularvelocityindps. 40 vi ListofFigures vii Figure22 Heelstrikes detected by algorithms and insoles duringPWS.Theverticalaxisrepresentsthean- gularvelocityindps. 40 Figure23 Average MAE- and MAEr-values of ICs during PWS.Theverticalaxisrepresentstheamountof samples. 43 Figure24 AverageF1-score,Precision&RecallofICsdur- ingPWS. 43 Figure25 Comparison of the events detected on the left andrightsideofthebody.Theverticalaxisrep- resentstheamountofsamples. 45 Figure26 Comparison of the events detected on the left andrightsideofthebody 46 Figure27 Comparisonoftheeventsdetectedbydatagath- eredattheankles,sacrumandshanks 46 Figure28 AverageMAE-andMAEr-valuesofTOsduring PWS.Theverticalaxisrepresentstheamountof samples. 47 Figure29 AverageF1-score,Precision,Recall-valuesofICs duringPWS. 47 Figure30 ComparisonoftheTOsdetectedontheleftand right side of the body. The vertical axis repre- sentstheamountofsamples. 49 Figure31 ComparisonoftheTOsdetectedontheleftand rightsideofthebody 49 Figure32 Comparison of the TOs detected by data gath- eredattheankles,sacrumandshanks 50 Figure33 SpreadoftheamountofTOsdetectedbytheal- gorithmssubtractedfromtheamountofTOsde- tectedbytheinsolesduringPWS 53 Figure34 SpreadoftheamountofTOsdetectedbytheal- gorithmssubtractedfromtheamountofTOsde- tectedbytheinsolesduringSWS 53 Figure35 AverageMAE&MAErbetweenICsdetectedby algorithmsandinsolesduringSWS.Thevertical axisrepresentstheamountofsamples. 54 Figure36 AverageF1-score,Precision&RecallofICsdur- ingSWS. 54 Figure37 Comparison of the events detected on the left andrightsideofthebody 55 Figure38 Comparison of the events detected on the left andrightsideofthebody.Theverticalaxisrep- resentstheamountofsamples. 55 Figure39 Comparisonoftheeventsdetectedbydatagath- eredattheankles,shanksandsacrum 57 viii ListofFigures Figure40 AverageMAE MAEroftheTOsdetectedbyal- gorithms and insoles during SWS. The vertical axisrepresentstheamountofsamples.Thezero- value should be interpreted as the worst value possible. 58 Figure41 AverageF1-score,Precision&RecallofTOsdur- ingSWS. 58 Figure42 ComparisonoftheTOsdetectedontheleftand rightsideofthebodyduringSWS 60 Figure43 Comparison of the MAE(r) of the TOs detected ontheleftandrightsideofthebodyduringSWS. Theverticalaxisrepresentstheamountofsam- ples. 60 Figure44 Comparison of the TOs detected by data gath- eredattheanklesandshankduringSWS 61 Figure45 Comparison of the MAE(r) of the TOs detected bydatagatheredattheanklesandshankduring SWS.Theverticalaxisrepresentstheamountof samples. 63 Figure46 AverageMAE&MAErbetweenICsdetectedby algorithmsandinsolesduringSWS.Thevertical axisrepresentstheamountofsamples. 64 Figure47 AverageF1-score,Precision&RecallofICsdur- ingFWS. 65 Figure48 Comparison of the events detected on the left andrightsideofthebody 65 Figure49 Comparison of the events detected on the left andrightsideofthebody.Theverticalaxisrep- resentstheamountofsamples. 67 Figure50 Comparisonoftheeventsdetectedbydatagath- eredattheankles,shanksandsacrum 68 Figure51 AverageMAE&MAErbetweenTOsdetectedby algorithmsandinsolesduringFWS.Thevertical axisrepresentstheamountofsamples. 68 Figure52 AverageF1-score,Precision&RecallofTOsdur- ingFWS. 69 Figure53 ComparisonoftheTOsdetectedontheleftand rightsideofthebodyduringFWS 69 Figure54 Comparison of the MAE(r) of the TOs detected ontheleftandrightsideofthebodyduringFWS. Theverticalaxisrepresentstheamountofsam- ples. 70 Figure55 Comparison of the TOs detected by data gath- eredattheanklesandshankduringFWS 71 Figure56 Comparison of the MAE(r) of the TOs detected bydatagatheredattheanklesandshankduring FWS.Theverticalaxisrepresentstheamountof samples. 71 Figure57 Placementofthesensors(front)(1) 85 ListofFigures ix Figure58 Placementofthesensors(side)(2) 85 Figure59 Placementofthesensors(back)(3) 86 LIST OF TABLES Table1 Total amount of steps collected for every per- sonduringPreferredWalkingSpeed(PWS),Fast Walking Speed (FWS) and Slow Walking Speed (SWS). Note that the overall trend seems to be thatwalkingslowerresultsinmore(andsmaller) steps for the same distance and walking faster resultsinlesssteps.OnlyP7seemstobreakthis trend. 17 Table2 Overviewofalgorithmsused 24 Table3 Amount of ICs detected by the algorithms sub- tracted from the amount of ICs detected by the insolesduringPWS 42 Table4 AmountofTOsdetectedbythealgorithmssub- tractedfromtheamountofTOsdetectedbythe insolesduringPWS 42 Table5 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheeventsdetectedatbothsidesofthe body 45 Table6 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheTOsdetectedonseparatesidesof thebody 48 Table7 AmountofICsdetectedduringSWS 52 Table8 AmountofTOsdetectedduringSWS 52 Table9 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheeventsdetectedatbothsidesofthe bodyduringSWS 57 Table10 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheTOsdetectedonseparatesidesof thebodyduringSWS 61 Table11 Amount of ICs detected by the algorithms sub- tracted from the amount of ICs detected by the insolesduringFWS 63 Table12 AmountofTOsdetectedbythealgorithmssub- tractedfromtheamountofTOsdetectedbythe insolesduringFWS 64 Table13 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheeventsdetectedatbothsidesofthe bodyduringSWS 67 Table14 ComparisonoftheaverageF1,PrecisionandRecall- valuesfortheTOsdetectedonseparatesidesof thebodyduringFWS 70 Table15 GlobalresultsforICs,rankedoninitialresult 73 x
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