Su-ting, Chuang 2010/8/2

Outline Introduction Related Work System and Method Experiment Conclusion & Future Work 2

Outline Introduction Related Work System and Method Experiments Conclusion & Future Work 3

Introduction 4

Outline Introduction Related Work System and Method Experiments Conclusion & Future Work 5

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

Related Work DI (Diffused Illumination) J. Rekimoto and N. Matsushita, “Perceptual surfaces: Towards a human and object sensitive interactive display," Workshop on Perceptural User Interfaces (PUI'97),

Related Work TouchLib A multi-touch development kit Finger detection processing flow chart 8 Background Subtraction Simple Highpass ScaleThreshold

Outline Introduction Related Work System and Method Experiments Conclusion & Future Work 9

Hardware Configuration (2) IR Camera (3) IR Illuminator (1) Peripheral Projector 10

Hardware Configuration Order of diffuser layer and touch-glass layer 11 Diffuser layer IR illuminator IR camera spot IR illuminator IR camera Touch-glass layer IR camera spot IR camera

Hardware Configuration Problem: IR rays will be reflected by the touch-glass and resulting hot spot regions in camera views Solution: Use other cameras to recover the regions which are sheltered by IR spots 12

Software Architecture Detection system Image Stitching Finger Detection Finger Tracking Parameter determination 13 Image Stiching Image Stiching Finger Detection Finger Detection Finger Tracking Finger Tracking

Software Architecture DirectShow Filter-based framework GShow GPU-accelerated framework 14

Image Stitching 15 Image Blending IR Camera IR camera Undistortion HomoWarp

Image Stitching HomoWarp Goal Unify finger size among different position of table 16

Image Stitching HomoWarp Method Calculate homography in advance

Image Stitching HomoWarp Warp image from each camera to virtual space 18

Image Stitching Image Blending 19

Parameter Determination Requirements of ideal finger detection system Sensitive Noise-free Evaluation of parameters Data Collection Depict trace Measurement Minimize miss and false alarm 20 Miss False Alarm

Parameter Determination Ideal finger detection Only one fingertip landing on trace Continuity among frames 21

Parameter Determination 22

Parameter Determination 23 Parameters Determinator Parameter Combination Detection Result Applicable set of Parameters Test Set Touch Data Ground Truth (Trace) Detection System

Outline Introduction Related Work System and Method Experiments Conclusion & Future Work 24

Experiments Performance evaluation 25

Experiments Parameter determination Decide parameters in our system Adopt sampling-based parameter search technique 26 Normalization Difference of Gaussian Background Subtraction Binary Finger Analysis Subtract value Smooth kernel Smooth kernel Threshold Finger Size Finger Size

Experiments Parameter determination Exhaustive search Parameter combination 5 (step) *5 (step) *5 (step) *5 (step) = 625 Applicable parameter num 16/625 = 2.56% 27 Subtract value Smooth kernel ThresholdFinger size Low bound 0510 Step55510 High bound

Experiments Parameter determination Particle filtering 28 Sampling Measure

Experiments 29

Experiments 30

Outline Introduction Related Work System and Method Experiments Conclusion & Future Work 31

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