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Analysis of Body Movement and Its Effects on Cyberware 3D Whole ANALYSIS OF BODY MOVEMENT AND ITS EFFECTS ON CYBERWARE 3D WHOLE BODY SCANNER A Thesis Presented to The Faculty of the Fritz J. and Dolores H. Russ College of Engineering and Technology Ohio University In Partial Fulfillment of the Requirement for the Degree Master of Science By Anmin Hu August, 1999 OHIO UNIVERSITY LIBRARY ACKNOWLEDGEMENTS I, Anmin Hu, would like to take this opportunity to thank several people who make thesis become possible. First, I would like to express my deep appreciation and thanks to my advisor, Dr. Joseph H. Nurre, for his directions. He has been so kind and patient to help me when I had problems. "Thanks a lot! Dr. Nurre". I would like to thank my friend, Collier Jeff and Lewark Eric, who are the graduate students of Dr. Nurre. They always gave me hints and help when I had the troubles. This helps me a lot. I would like to thank Mr. Brian Comer, who is research scientist in US Army Natick RD&E Center, to provide the 3D scan data. Without his assistance, this thesis can not be formed. I also would like to thank Dr. Jeffrey Giesey, Dr. Mehmet Celenk to be the members of the thesis committee and Dr. Bhavin Mehta to be the college representative of the thesis committee. Thanks for your time to revise my thesis. Contents Chapter One Introduction 1 Chapter Two Literature Review 5 Chapter Three Body Sway Analysis in Cyberware WB4 Scanning 10 3.0 Introduction 10 3.1 Analysis Method 10 3.1.0 The Cyberware Whole Body Scanner 10 3.1.1 Scan the Subject with the Cylinder Attached 12 3.1.2 Post-Processing of 3D Cylinder Surface Data 14 3.2 Software Implementation 18 3.2.0 Data Sort by Z Cordinate 18 3.2.1 Implementing Furthest Point Analysis Algorithm 18 3.3 Verification of the Analysis Method and its Implementation 19 Chapter Four Simulation and Analysis of Body Sway Using Jack Package 27 4.0 Introduction 27 4.1 Develop the Human Body Model Using Jack 27 4.1.0 Peabody Object Representation 27 4.1.1 Develop a Model Based on Peabody Language 28 4.2 Software Simulation of Body Movement Using the Model 28 4.2.0 Introduction 28 4.2.1 Lisp Interface and JCL 28 4.2.2 C&C++ API 29 11 4.2.3 Network Jack 30 4.2.4 Software Simulation Methods 31 4.3 Software Implementation of 'jackmove' 33 4.3.0 Introduction 33 4.3.1 Establish RPC connection between Jack Program and 'jackmove' Program 33 4.3.2 Specify the Movement of the Center of Gravity 34 4.3.3 Adjust Joint 35 4.3.4 Initialize Node Position and Apparel Length 36 4.3.5 Analyze the Body Movement 38 4.3.6 Analyze the Apparel Measurement Error 39 4.3.7 User Interface 39 Chapter Five Results 43 Chapter Six Conclusion and Future Research 52 Bibliography 54 Appendix l.x C Programs for Chapter Three 56 Appendix 1.0 measure.h 56 Appendix 1.1 measure.c 57 Appendix 1.2 plyLoad.c 58 Appendix 1.3 dataSortByZ.c 61 Appendix 1.4 dataStatistic.c 63 Appendix 1.5 cutoff.c 65 Appendix 1.6 dataAnalysis.c 66 iii Appendix 1.7 calculate.c 67 Appendix 2.x C Programs for Chapter Four 70 Appendix 2.0 capi.h 70 Appendix 2.1 main.c 71 Appendix 2.2 move_center_gravity.c 72 Appendix 2.3 adjustJoint.c 73 Appendix 2.4 datalnit.c 78 Appendix 2.5 initial_Iength.c 79 Appendix 2.6 picknewpoint.c 80 Appendix 2.7 showmovement.c 81 Appendix 2.8 showlengtherror.c 82 Appendix 2.9 shownode.c 84 Appendix 2.10 mainmenu.c 85 Appendix 2.11 jointmenu.c 86 Appendix 2.12 nodemenu.c 87 iv Figures Figure 3.1 The Cyberware Whole Body Scanner 11 Figure 3.2 The Researcher uses Cyberware WB4 scanner to collect the Human body anthropometric data in a simple pose 12 Figure 3.3 Subject with Cylinder Attached to His Front Torso Showing Scanning Position 13 Figure 3.4 Cylinder extracted from whole body scan 13 Figure 3.5 An Actual Z-slice of the Cylinder in 2D 14 Figure 3.6 A Diagram to Show How to Implement 'Furthest Point Algorithm' 16 Figure 3.7 A Linked-list to Store the Furthest Point for all Z-slices 19 Figure 3.8 A Static Cylinder is Scanned 20 Figure 3.9 A Moving Cylinder is Scanned 20 Figure 3.10 The Graph for Static Cylinder Scan 22 Figure 3.11 The Graph for Moving Cylinder Scan 23 Figure 3.12 The Graph for Moving Cylinder Scan 24 Figure 3.13 The Graph Showing the Subject's Intentional Sway 25 Figure 3.14 The Graph Showing the Subject's Intentional Sway 26 Figure 4.1 Jack Model 29 Figure 4.2 Network Jack and its Implementation 31 Figure 4.3 User Interface I 40 Figure 4.4 User Interface II 41 Figure 4.5 User Interface III 42 Figure 5.1 First Scan of the Subject Fitted with Cylinder 44 v Figure 5.2 Second Scan of the Subject Fitted with Cylinder 45 Figure 5.3 Third Scan of the Subject Fitted with Cylinder 46 Figure 5.4 Fourth Scan of the Subject Fitted with Cylinder 47 Figure 5.5 Fifth Scan of the Subject Fitted with Cylinder 48 vi Tables Table 1. Body Sway From the Five Scans 50 Table 2. Anthropometric Measurement Errors From the Five Scans 50 CHAPTER ONE INTRODUCTION Variations in human body size are tremendous. Both military and civilian industry frequently use anthropometric data to access the range of body size within their target populations. These comparative measurements guide the design and sizing of uniforms and other apparel. Engineers also use these data to optimize the layout of vehicles and workstations with respect to key parameters, such as reach, clearance, egress, and ingress. So, where does the anthropometric data come from? Traditional methods are based on measurements, such as segment lengths, breadths, and circumferences. These measurements were obtained with standard tools including anthropometers, calipers, and tape measures. However, within the past ten years, the state-of-the-art in anthropometric data collection has moved away from these tools toward non-contact 3D scanning. This trend began with scanning systems in the mid-1980s for the head, face, and other body segments and has recently evolved into whole-body scanning. Two primary technologies of the whole-body scanning system have emerged in the United States as valuable candidates for surface digitizing and measurement of the human body. Both are optically based and non-contact. The laser-based scanning system was developed and marketed by Cyberware Inc. in Monterey, California. A moire-based light-projection system was developed for commercialization by Textile and Clothing Technology Corporation in Cary, North Carolina. 2 The whole body scanning system, built by Cyberware, employs a laser-scanning triangulation method to acquire 3D images. In this design, a stripe of light is emitted from four laser diodes onto the scanning surface, then viewed simultaneously from two locations using an arrangement of mirrors. Viewed from an angle, the laser stripe appears deformed by the object's shape. These deformations are recorded by a CCD sensor and digitized. The cameras positioned with each of four scanning heads record this surface information as the scan heads traverse the length of the scanning volume from top to bottom. The separate data files from each scanning head are then combined in software to yield a complete integrated image of the scanned object. The Cyberware whole-body scanning system can image a person's surface and provide data for further post-processing. The scanned volume is approximately equal to a 2-meter high by 1.2-meter diameter cylinder. These dimensions accommodate the vast majority of human subjects. The spatial resolution of image ranges 5 millimeters in the x­ axis, 2 millimeters in the y-axis, and 2 millimeters along the z-axis. Scanning speed for the maximum scanned volume is around 17 seconds, which yields about 400,000 3D coordinates on the surface of an adult human body. The first two commercial whole-body scanning systems built by Cyberware have been delivered to both the U.S. Army Natick RD&E Center and the U.S. Air Force's Computerized Anthropometric Research and Design Laboratory. Researchers in the Computerized Anthropometric Research and Design Laboratory used the Cyberware scanner principally for aircrew-helmet and oxygen mask design, as well as for medical applications for bum victims and amputees. The Human Engineering Division of Armstrong Laboratory at Wright-Patterson introduced the Cyberware whole-body scanner 3 to improve the fit of commercial and military clothing, while bettering the design of aircraft cockpits and crew stations. Of course, civilian applications for the Cyberware whole body scanner could be as valuable as those for military applications. For example, the apparel industry is intensely interested in scanning people for potentially more affordable, custom-tailored clothes. Although the laser-based 3D whole body scanning system has been put into commercial applications, some hurdles still confront the mainstream use of this promising technology. Some problems are fundamental - data accuracy and reliability, for example - and will affect all potential applications. This thesis will focus on the basic research conducted on 3D data digitizing accuracy and reliability. The Cyberware whole body scanner images the human body for about 17 seconds as the cameras travel from head to toe. This process yields thousands of digitized profiles from each of the scanning heads.
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