vision-based finger detection and its applications
DESCRIPTION
Master Thesis Presentation by Chuang Yi-Fan, Image and Vision Lab, Graduate Institute of Networking and Multimedia, National Taiwan UniversityTRANSCRIPT
Vision-Based Finger Detectionand Its Applications
基於電腦視覺之手指偵測及其應用
Yi-Fan Chuang
Advisor: Prof. Yi-Ping Hung Prof. Ming-Sui Lee
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
2
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
3
Introduction
Interactive systemBare-handed operations are more intuitive to
manipulate digital objects directlyInteractions
• Users: hover/touch gestures• Objects: rotation, scaling, selection, special effects….
Use computer vision techniques• Fingertip detection• Fingertip tracking
4
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
5
Related Work
Enhance DeskFingertip finding
• Template matching
Palm finding• Morphological erosion
H. KOIKE and Y. KOBAYASHI, “Integrating paper and digital information on enhanceddesk: a method for realtime finger tracking on an augmented desk system,“ ACM Transation Computer-Human Interaction, vol. 8, no. 4, pp. 307-322, 2001.
Related Work
FTIR (Frustrated Total Internal Reflection)
J. Y. Han, “Low-cost multi-touch sensing through frustrated total internal reflection," in Proceedings of the 18th annual ACM symposium on User interface software and technology (UIST '05). New York, NY, USA: ACM Press, 2005, pp. 115-118.
Related Work
Visual TouchpadFingertip detection
• Curvature of contour• Finger Orientation
Touch detection• Two warp images
S. Malik and J. Laszlo, “Visual touchpad: a two-handed gestural input device," in Proceedings of the 6th international conference on Multimodal interfaces (ICMI '04). New York, NY, USA: ACM Press, 2004, pp. 289-296.
Related Work
PlayAnyWhereTouch and Hover
• Use appearance of shadows
A. D. Wilson, “Playanywhere: a compact interactive tabletop projection-vision system," in Proceedings of the 18th annual ACM symposium on User interface software and technology (UIST '05). New York, NY, USA: ACM Press, 2005, pp. 83-92.
Related Work
Comparison
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Enhance Desk
(CHI 01’)
FTIR
(UIST 05’)
Visual Touchpad (ICMI 04’)
PlayAnyWhere
(UIST 05’)
MethodTemplate matching
Connected component
analysis
Curvature of contour
Shadow
Detection Touch TouchTouch/Hover(2 cameras)
Touch/Hover(1 camera)
DisadvantageOne user
Only touchOnly touch One user
One finger for one palm
Our Work: Touch/Hover (1 camera) Multi-user with multi-finger
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
11
Overview
System setupAn IR camera with IR illuminators to observe
hands
J. Rekimoto and N. Matsushita, “Perceptual surfaces: Towards a human and object sensitive interactive display," Workshop on Perceptural User Interfaces (PUI'97), 1997.
Direct observation• Clear shapes
Indirect observation• Unclear shapes
System setupDirect observation
• Clear shapes
Indirect observation• Unclear shapes
OverviewClear shapes (MaC Ball)
GestureCaptured
image
System setupDirect observation
• Clear shapes
Indirect observation• Unclear shapes
Overview
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Unclear shapes (i-m-Top)
Gesture Captured image
Overview
Fingertip detection
Fingertip tracking
Detection results Kalman filtering
Backgroundsubtraction
Morphological opening
Difference of previous two
Principalcomponent
analysis
Fingertipdetection
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Fingertip Detection
Background subtraction
ObservationContact area leaves strong reflection
(Enhanced image)
Backgroundsubtraction
Morphological opening
Difference of previous two PCA
Fingertipdetection
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Fingertip Detection
Extract finger partUse a morphological opening operation
• The size of structuring element is larger than that of a normal finger and smaller than a palm.
Original
Morphological opening
Finger
(Enhanced image)
Backgroundsubtraction
Morphological opening
Difference of previous two PCA
Fingertipdetection
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Fingertip Detection
Difference and binarization
Principal component analysisFinger direction
Possible fingertips’ positions
(Enhanced image)Backgroundsubtraction
Morphological opening
Difference of previous two PCA
Fingertipdetection
Backgroundsubtraction
Morphological opening
Difference of previous two PCA
Fingertipdetection
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Fingertip Detection
Template matching (pattern matching)TemplateRemove false matchings
• Distance check• Diagonal check
Backgroundsubtraction
Morphological opening
Difference of previous two PCA
Fingertipdetection
Finger patch
Detection Results on i-m-TopFingertipdetection
Difference of previous two
& PCA
Morphologicalopening
Background subtraction
(Enhanced image) Separate finger touching and palm hovering
Detection Results on MaC Ball
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Fingertip Tracking
Kalman filterSmooth the path
• Predict the new state and its uncertainty• Correct the tracker with its new measurement• Assume white noise and uniform velocity
Original
After Kalman filter
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Performance Evaluation
Real-time system is possible
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Outline
IntroductionRelated WorkFingertips Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
24
Hardware Configuration
i-m-TopInteractive Multi-resolution Tabletop
Cooperate with Yi-Wei Chia25
Hardware Configuration
i-m-TopInteractive Multi-resolution Tabletop
Cooperate with Yi-Wei Chia26
Software Implementation
Fingertip detection and trackingPalm detection and trackingAssociation between fingertips and palmsPen detectionPriority of pens and palmsEvents definitions
27
Palm Detection and Tracking
Palm detectionThe average
position is picked as palm position
Palm trackingKalman filtering
Palmdetection
Morphological opening
(Palm part)
Background subtraction
(Enhanced Image)
Association between Fingertips and Palms
Allocate fingertips to palmsUse the angle and the distance between
fingers and palms
,*
,),(cos1,minarg
m
diri
dirposi
pos
j
pp
pfAnglepfm
(Enhanced Image)29
Pen Detection and Priority
Pen DetectionUse a higher threshold
Priority of pens and palmsHigher priority for the pen tip
• If there is a palm around the pen tip, this palm and the fingertips associated to the palm will be ignored.
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Events Definitions
HoverPalm position
TouchPalm positionFinger position and its correspondent palmPen position
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Application I: Browsing and Editing
OperationsDrag photo/documentZoom in and zoom outStrokeMove the foveal area
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Application II:Video Retrieval System
OperationsQueryBrowseFeedback
33Video
Top button
Video plane Video wall
Scroll bar
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
34
Magic Crystal Ball (MaC Ball)
An interactive 3D displaySlide fingers (like a wizard) on the ball surface
to control the content
35
Hardware Configuration
IR Camera IR Illuminator
Pressure Sensors
User
Transparent Glass Ball
Reflection Mirror
Fresnel Lens
LCD
Display Module Detection Module
Software Implementation
Fingertip detection and trackingDetect fingertips’ positionsPointing gesture
Motion detectionOptical flow algorithmWaving gesture
Contact DetectionPressure Sensor (Flexi Force)
• Detect whether users touch MaC Ball
Software Implementation
Contact detection – Pressure SensorsObservation
p1 p2p3p1 p2 p1 p2
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Events Definitions
Gesture switch
Pointing Gesture
FingertipsDetection
MotionDetection
MotionDetection
FingertipsDetection
Waving Gesture
Pressuresensors
Touch / Hover 39
Application:Virtual Exhibition
OperationsRotateSelectMagnifierChange relics
40Video
Outline
IntroductionRelated WorkFingertip Detection and TrackingApplications
i-m-Top Magic Crystal Ball (MaC Ball)
Conclusion & Future Work
41
Conclusion & Future Work
Multi-finger detection techniquesSimple and real-timeCost-effective and flexible
Applications i-m-Top: interactive interfaceMaC Ball: interactive 3D display
Future workUse FTIR to enhance the accuracy of fingertip
detection More gestures for interactive systems
42