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The OU-ISIR Gait database Comprising the Large Population Dataset and Performance Evaluation of Gait RecognitionIntroductionGait-based biometrics at a distance Application to wide-area surveillance

2FingerprintIrisDNAFaceDistance from a sensorNearFarPrecisionHighLow

Gait database is essential for the development of gait-based biometrics

Gait

2Related workExisting major gait database3CASIAYu et al. 2006USFSarkar et al. 2005OU-ISIR TreadmillMori et al. 2010Mannami et al. 2010Large populationOkumura et al. 2010Makihara et al. 2011SotonNixon et al. 2001Number and diversity of subjectsSmallLargeVariation in walking conditionsLargeSmall At most 185 subjects Genders and ages are biasedPerformance evaluation with statistical reliabilityEvaluation of the robustnessNumber and diversity of subjects Camera pose variations introduce bias into the evaluation results

3ObjectiveConstruction of the worlds largest gait databaseFocus on Number and diversity of subjects

Investigation of the upper limit of gait-recognition performance in statistically reliable way

Study on the difference of gait-recognition performance between genders and age groups44Proposed dataset The OU-ISIR Gait Database, Large Population Dataset (OU-LP)Major upgrade of previous works1,035 subjects in Okumura et al. 20101,728 subjects in Makihara et al. 2011

Extensions from the previous worksNumber of subjects : 4,0072,135 males and 1,872 females with age ranging 1 to 94 year old

All silhouette images are normalizedBiases of camera rotation are removed

Observation angles of subjects are specifically definedPrevious work merely defined as side view

5Statistically reliable evaluationMore equitable evaluationFair analysis in terms of the observation angles5Capturing system63 m (approx.)3 m (approx.)4 mCaptureintervalStartGreen panel Acceleration sectionDeceleration sectionCamera 2Camera 1EndWalking courseGreen carpet4 m (approx.)

Point Grey research Flea2

Image size VGA (640 by 480 pixel)

Frame-rate 30 fps

Camera 16Data collectionIn conjunction with demonstration in five exhibitions

Each subjectSigned release agreement for research-purpose useProvided gender and age information7ExhibitionTerm#Days#Visitors (approx.)Outreach activity in DIM (Dive Into the Movie) projectMarch 200931,6005th Regional Disaster and Crime Prevention ExpoJune 20102280Open campus at Osaka university 2010Aug 2010170Open campus at Osaka university 2011Aug 2011190Outreach activity in CREST projectAug 201152,0007Statistics of OU-LPNumber of subjects : 4,007 (2,135 males and 1,872 females)Distributions of subjects gender and age

Examples8

8Two primal subsets2 sequences/subject : OU-LP-A1 sequence/subject : OU-LP-B

Subsets of OU-LP9Evaluation of recognition performanceInvestigation of gender/age estimation9Two primal subsets2 sequences/subject : OU-LP-A1 sequence/subject : OU-LP-B

Further subsets based on observation angle

Subsets of OU-LP10XYCamera center: Subject

: Observation angleWalking directionSurface of wall (green panel): Line of sight

ZA section of 55 [deg]-centered gait period

A section of 65 [deg]-centered gait period

A section of 75 [deg]-centered gait period

A section of 85 [deg]-centered gait period

Evaluation of recognition performanceInvestigation of gender/age estimation10Two primal subsets2 sequences/subject : OU-LP-A1 sequence/subject : OU-LP-B

Further subsets based on observation angleNumber of subjects

Subsets of OU-LP11Primal subsetObservation angleTotal55 [deg]65 [deg]75 [deg]85 [deg]AllA3,7063,7703,7513,2493,1413,835B3,9984,0054,0023,9233,9044,007A/B-55A/B-65A/B-75A/B-85A/B-AllEvaluation of recognition performanceInvestigation of gender/age estimation11AdvantagesLarge population4,007 subjects in totalApprox. 20 times more than the existing public gait database

Whole generationAge range from 1 to 94 yrsEach 10-year intervals contains over 400 subjects (from 5 to 49 yrs)

Gender balanceMale : Female = 1.1 : 1

Silhouette qualityAll the silhouette images are visually checked at least twice and manually modified if necessary1212PreprocessingSilhouette extraction13

Original sequenceSilhouette sequenceManual denoising if necessary Background subtraction

Camera-pose variationDirect use introduces some biases in evaluation results13PreprocessingCorrection of camera rotation14XZYImage planeCamera coordinate systemzxySubjectXZYImage planeCamera coordinate systemzxySubject

Original captured imageDistortion corrected imageRotation corrected image[Tsuji et al. 1985]

Vertical center of image Rotation correction by using vanishing points14PreprocessingCreation of size-normalized silhouette15

Original sequenceSilhouette sequenceBackground subtraction

Rotation correction

Size-normalized silhouette sequence88 x 128 pixel

Registration and size-normalization15Gait recognition approach16Period detectiontP

Gait period detectionGait feature creation : appearance and period-based features

Gait Energy Image (GEI)Frequency Domain Feature (FDF)Gait Entropy Image (GEnI)Gait Flow Image (GFI)Chrono-Gait Image (CGI)Masked GEI (MGEI)Gait feature matching

Probe

GalleryDirect matchingDissimilarity is measured by L2 normHan and Bhanu 2006Makihara et al. 2006Lam et al. 2011Wang et al. 2010Bashir et al. 2009Bashir et al. 201016ExperimentsPerformance evaluation of gait recognition1. Effect of number of subjects2. Comparison of gait feature3. Effects of gender and age

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Performance evaluation of gait recognitionEffect of number of subjectsData set: OP-LP-A-65 (3,770 subjects)Reliability comparison: Whole set vs. Subset (100 subjects)Gait feature: GEI

18Estimated standard deviation

: observed FRR: #subjectsGray bar: observed deviation in 100 different subsetsROC curve

[Snedecor and Cochran 1967]Performance evaluation of gait recognitionGait feature comparisonData set: OP-LP-A-All (3,141 subjects)19

Performance older was almost independent of the observation angleGEI FDF > CGI GEnI > GFI > MGEIPerformance orderROC curveCMC curveBetter performanceBetter performance

GEIFDFCGIGFIGEnIMGEIPerformance evaluation of gait recognitionEffects of gender and ageData set: OP-LP-A-65 (3,770 subjects)Gait feature: GEIPerformance comparison between gender/age groupsNumber of subjects

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5-year interval10-year interval

Performance evaluation of gait recognitionEffects of genderEqual Error Rate (EER) among genders and age groups

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Better performancePerformanceFemale > Male

Dissimilarity distributionDissimilarity distributionIntra-subject variations: Female MaleInter-subject variations: Female > MaleIntraInterPerformance evaluation of gait recognitionEffects of ageEqual Error Rate (EER) among genders and age groups

Better performanceGradual improvement22

Dissimilarity distribution of the same subjectsMaleFemaleDissimilarityDissimilarityAgeAgeGait fluctuation is small Adults have fixed gait patternImmaturity of childrens walking causes large intra-subject gait fluctuationPerformance evaluation of gait recognitionEffects of ageEqual Error Rate (EER) among genders and age groups

Better performanceGradual improvement23

Dissimilarity distribution of the same subjectsMaleFemaleDissimilarityDissimilarityAgeAge

Conclusion and future workConclusionWe constructed the worlds largest gait database The number of subjects: 4,007Age range: 1 to 94 yrs Gait-recognition performance is evaluated with statistically reliabilityComparison of state-of-the-art gait representationStudy on the performance difference between genders and age groups

Future workData collection of very young child and elderly

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