Generation of Postured Voxel-based Human Models Used for Electromagnetic Applications.
Technische Universität, Darmstadt
[Ph.D. Thesis], (2012)
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|Item Type:||Ph.D. Thesis|
|Title:||Generation of Postured Voxel-based Human Models Used for Electromagnetic Applications|
The main contribution of this dissertation is the development of a poser program package, which can deform a voxel-based human body model named HUGO to allow the genera-tion of common postures that people often use in normal life. To illustrate the usefulness of this poser program, two electromagnetic applications are presented. As a low frequency application example in electrical engineering, the first one simulates and analyzes the step voltage due to a lightning strike in detail with the help of two postured human body models. The second one studies the influence of human’s posture on specific absorption rate (SAR) calculation as a high frequency electromagnetic application example. With the development of medical technique, computer graphics and computational elec-tromagnetics, high resolution and anatomically realistic whole-body voxel-based human models have been recently developed and widely used in computation of induced elec-tromagnetic fields and SAR in the human body. However, voxel models’ unchangeable posture strongly limits related researches when simulating a realistic scenario in which people have a lot of different postures. In this dissertation, a poser program package, which is an improved version of the well known free form deformation (FFD) technique in computer graphics, was developed to overcome this problem. The poser program can import and render the original voxel dataset, set rotation angles of different joints with a simplified human model, generate postured human models, and export the postured hu-man models as new voxel dataset files. With its help, the original voxel-based human model can be deformed smoothly, continuity of internal tissues and organs can be main-tained, and masses of different tissues and organs can be conserved at a reasonable level. In order to generate a postured human model with correctly anatomic structure, a segmen-tation approach was developed to separate arms away from the trunk. Deformation of the knee joint was dealt with separately to avoid unreasonable deformation of the femur and tibia, and to realize movement and rotation of the patella when the knee joint is bent. As a typical application of the postured human models, internal electromagnetic fields in the walking and standing human body shocked by the step voltage caused by broken power line or lightning strike were simulated. In order to get a much longer stable time step than the value specified by the Courant limit for stability, the reduced c technique was applied for the first time to these electro-quasistatic simulations, after a thorough study. At last, because human’s posture can significantly affect the way in which the hu-man body absorbs electromagnetic radiation, whole body averaged SAR and localized SAR distribution of a sitting human model were calculated and compared to that of the standing human model for various incidence angles of the electromagnetic wave and for different environmental conditions.
|Place of Publication:||Darmstadt|
|Classification DDC:||000 Allgemeines, Informatik, Informationswissenschaft > 004 Informatik
600 Technik, Medizin, angewandte Wissenschaften > 600 Technik
|Divisions:||Fachbereich Elektrotechnik und Informationstechnik
Fachbereich Elektrotechnik und Informationstechnik > Theorie Elektromagnetischer Felder
|Date Deposited:||25 Jan 2012 10:17|
|Last Modified:||07 Dec 2012 12:04|
|Referees:||Weiland, Prof. Dr.- Thomas and Munteanu, Prof. Dr.- Irina and Anderl, Prof. Dr.- Reiner|
|Refereed:||11 January 2012|