Title page

Abstract

Contents

1. Introduction 12

1.1 Motivation 12

1.2 Background 14

1.3 Goals 15

1.4 Outline 16

2. Related works 17

2.1 Vision-based systems 17

2.1.1 Bare-Hand Human-Computer Interaction 18

2.1.2 Perceptual Surfaces : Towards a Human and Object Sensitive Interactive Display 18

2.1.3 Enhanced Desk and Enhanced Wall : Augmented Desk and Wall Interfaces with Real-time Tracking of User s Motion 19

2.2 Electric-field sensing systems 19

2.2.1 A Multi-touch three dimensional touch-sensitive tablet 21

2.2.2 Smart Skin : An Infrastructure for Freehand Manipulation on Interactive Surfaces 22

2.2.3 Electric Field Sensing for Graphical Interfaces 23

3. Analysis of the early version system 25

3.1 Overview 25

3.2 System architecture 25

3.2.1 The signal processing unit 26

3.2.2 The proximity sensing unit 29

3.2.3 The image processing unit 30

3.2.4 The 3D display unit 30

3.3 Experimental results 32

3.4 Discussion 37

4. The 3D Sensor Table 38

4.1 Overview 38

4.2 System architecture 40

4.2.1 The proximity sensing unit 40

4.2.2 The signal processing unit 51

4.2.2.1 Master processing unit 52

4.2.2.2 The RX processing unit 54

4.2.3 The 3D display unit 57

4.2.4 The image processing unit 58

4.3 Software algorithms 59

4.3.1 Proximity calibration 61

4.3.2 Location determination 66

4.3.3 Hand posture classification 78

4.4 Experimental results 85

4.4.1 Location determination 85

4.4.2 Hand posture classification 86

5. Conclusion and future works 87

5.1 Conclusion 87

5.2 Future works 89

국문요약 91

References 92

Acknowledgements 94

Table 1. The experimental results for proximity sensing 33

Table 2. The proximity values of RX circuit 34

Table 3. TX signal variations in TX channels 62

Table 4. The result of proximity calibration process 64

Table 5. The experimental result for investigating the changes of proximity value according to the height of hand at any crossing node 69

Table 6. The proximity value according to height of hand at arbitrary crossing nodes in fist-hand posture 74

Table 7. The proximity value according to height of hand at arbitrary crossing nodes In knife-shape hand posture 75

Table 8. The comparison of P10 s values according to hand shapes 83

Table 9. The difference value of the maximum proximity value and other proximity values in straight-hand posture and knife-hand posture according to the height of hand 84

Table 10. The experimental results for location determination 85

Table 11. The experimental results for hand-posture classification 86

Table 12. The performance of the 3D Sensor Table 88

Figure 1. Lumped circuit model of electric field sensing parameters(the image courtesy of Smith) 23

Figure 2. The early version system architecture of the 3D Sensor Table 25

Figure 3. The schematic diagram and real picture of the signal processing unit 28

Figure 4. The proximity sensing unit 29

Figure 5. The 3D display unit 31

Figure 6. The experimental results for proximity sensing in normal state 33

Figure 7. The schematic diagram of RX circuit 34

Figure 8. The system configuration of the 3D Sensor Table 39

Figure 9. The proximity sensing unit in the early version system 41

Figure 10. Electric field sensing technique for proximity measurement 43

Figure 11. The newly designed proximity sensing unit 46

Figure 12. The principle of proximity sensing 47

Figure 13. The overview of the signal processing unit 51

Figure 14. The master processing unit 52

Figure 15. The waveform generator, 33250A 53

Figure 16. The Rx processing unit 55

Figure 17. TX and RX signal 56

Figure 18. The 3D display unit 57

Figure 19. The process and output in the image processing unit 59

Figure 20. The analog switching with a capacitor 62

Figure 21. The distribution diagram of relative proximity data 65

Figure 22. The crossing nodes of the proximity sensing unit 66

Figure 23. The peak value finding method for the 2D position 67

Figure 24. The proximity value according to the height of hand 68

Figure 25. The diagram of proximity value distribution according to height of hand 71

Figure 26. The simple postures of hand 72

Figure 27. The proximity value according to hand-posture 73

Figure 28. The diagram of proximity distribution according to height of hand In fist-hand posture 76

Figure 29. The diagram of proximity distribution according to height of hand In knife-hand posture 77

Figure 30. The eleven crossing nodes used for hand-posture classification 79

Figure 31. The patterns for the fist-hand posture 80

Figure 32. The comparison of P₁and P10 between straight-hand posture and fist-hand posture 81

Figure 33. The comparison of maximum proximity values between straight-hand posture and knife-hand posture according to the height of hand 82