TY - THES A1 - Lamecker, Hans T1 - Variational and statistical shape modeling for 3D geometry reconstruction N2 - The reconstruction of geometric shapes plays an important role in many biomedical applications. One example is the patient-specific, computer-aided planning of complex interventions, which requires the generation of explicitly represented geometric models of anatomical structures from medical image data. Only solutions that require minimal interaction by medical personnel are likely to enter clinical routine. Another example is the planning of surgical corrections of deformities where the target shape is unknown. Surgeons are often forced to resort to subjective criteria. These applications still pose highly challenging reconstruction problems, which are addressed in this thesis. The fundamental hypothesis, pursued in this thesis, is that the problems can be solved by incorporating a-priori knowledge about shape and other application-specific characteristics. Here, we focus mainly on the aspect of geometric shape analysis. The basic idea is to capture the most essential variations of a certain class of geometric objects via statistical shape models, which model typical features contained in a given population, and restrict the outcome of a reconstruction algorithm (more or less) to the space spanned by such models. A fundamental prerequisite for performing statistical shape analysis on a set of different objects is the identification of corresponding points on their associated surfaces. This problem is particularly difficult to solve if the shapes stem from different individuals. The reason lies in the basic difficulty of defining suitable measures of similarity. In this thesis, we divide the correspondence problem into feature and non-feature matching. The feature part depends on the application, while the non-feature part can be characterized by a purely geometric description. We propose two different approaches. The first approach has proved useful in many applications. Yet, it suffers from some practical limitations and does not yield a measure of similarity. Our second, variational, approach is designed to overcome these limitations. In it, we propose to minimize an invariant stretching measure, constrained by previously computed features. An important property, which sets our method apart from previous work, is that it does not require the computation of a global surface parameterization. KW - correspondence problem KW - surface matching KW - image segmentation KW - model-based shape reconstruction KW - 2d-3d shape reconstruction Y1 - 2008 UR - http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000005805 ER - TY - GEN A1 - Günther, Andreas A1 - Lamecker, Hans A1 - Weiser, Martin T1 - Direct LDDMM of Discrete Currents with Adaptive Finite Elements N2 - We consider Large Deformation Diffeomorphic Metric Mapping of general $m$-currents. After stating an optimization algorithm in the function space of admissable morph generating velocity fields, two innovative aspects in this framework are presented and numerically investigated: First, we spatially discretize the velocity field with conforming adaptive finite elements and discuss advantages of this new approach. Second, we directly compute the temporal evolution of discrete $m$-current attributes. T3 - ZIB-Report - 11-22 KW - Large Deformation KW - Diffeomorphic Registration KW - Matching KW - Currents KW - Adaptive Finite Elements Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-13090 ER - TY - GEN A1 - Zilske, Michael A1 - Lamecker, Hans A1 - Zachow, Stefan T1 - Adaptive Remeshing of Non-Manifold Surfaces N2 - We present a unified approach for consistent remeshing of arbitrary non-manifold triangle meshes with additional user-defined feature lines, which together form a feature skeleton. Our method is based on local operations only and produces meshes of high regularity and triangle quality while preserving the geometry as well as topology of the feature skeleton and the input mesh. T3 - ZIB-Report - 07-01 KW - remeshing KW - non-manifold KW - mesh quality optimization Y1 - 2007 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-9445 ER - TY - GEN A1 - Ehlke, Moritz A1 - Ramm, Heiko A1 - Lamecker, Hans A1 - Hege, Hans-Christian A1 - Zachow, Stefan T1 - Fast Generation of Virtual X-ray Images from Deformable Tetrahedral Meshes N2 - We propose a novel GPU-based approach to render virtual X-ray projections of deformable tetrahedral meshes. These meshes represent the shape and the internal density distribution of a particular anatomical structure and are derived from statistical shape and intensity models (SSIMs). We apply our method to improve the geometric reconstruction of 3D anatomy (e.g.\ pelvic bone) from 2D X-ray images. For that purpose, shape and density of a tetrahedral mesh are varied and virtual X-ray projections are generated within an optimization process until the similarity between the computed virtual X-ray and the respective anatomy depicted in a given clinical X-ray is maximized. The OpenGL implementation presented in this work deforms and projects tetrahedral meshes of high resolution (200.000+ tetrahedra) at interactive rates. It generates virtual X-rays that accurately depict the density distribution of an anatomy of interest. Compared to existing methods that accumulate X-ray attenuation in deformable meshes, our novel approach significantly boosts the deformation/projection performance. The proposed projection algorithm scales better with respect to mesh resolution and complexity of the density distribution, and the combined deformation and projection on the GPU scales better with respect to the number of deformation parameters. The gain in performance allows for a larger number of cycles in the optimization process. Consequently, it reduces the risk of being stuck in a local optimum. We believe that our approach contributes in orthopedic surgery, where 3D anatomy information needs to be extracted from 2D X-rays to support surgeons in better planning joint replacements. T3 - ZIB-Report - 13-38 KW - digitally reconstructed radiographs KW - volume rendering KW - mesh deformation KW - statistical shape and intensity models KW - image registration KW - GPU acceleration Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-41896 SN - 1438-0064 ER - TY - CHAP A1 - Lamecker, Hans A1 - Lange, Thomas A1 - Seebaß, Martin T1 - Erzeugung statistischer 3D-Formmodelle zur Segmentierung medizinischer Bilddaten T2 - Proc. BVM 2003 Y1 - 2003 SP - 398 EP - 403 PB - Springer CY - Erlangen ER - TY - CHAP A1 - Lange, Thomas A1 - Lamecker, Hans A1 - Seebaß, Martin T1 - Ein Softwarepaket für die modellbasierte Segmentierung anatomischer Strukturen T2 - Proc. BVM 2003 Y1 - 2003 SP - 111 EP - 116 CY - Erlangen ER - TY - CHAP A1 - Lamecker, Hans A1 - Lange, Thomas A1 - Seebaß, Martin A1 - Eulenstein, Sebastian A1 - Westerhoff, Malte A1 - Hege, Hans-Christian T1 - Automatic Segmentation of the Liver for Preoperative Planning of Resections T2 - Proc. MMVR 2003 Y1 - 2003 SP - 171 EP - 173 PB - IOS press CY - Newport Beach, CA ER - TY - CHAP A1 - Lange, Thomas A1 - Lamecker, Hans A1 - Eulenstein, Sebastian T1 - Automatische Segmentierung von Lebergewebe für die präoperative Planung von Resektionen T2 - 1. Jahrestagung der Deutschen Gesellschaft für Computer- Roboterassistierte Chirugie CURAC Y1 - 2002 ER - TY - CHAP A1 - Seebaß, Martin A1 - Lamecker, Hans A1 - Gellermann, Johanna A1 - Wust, Peter T1 - The impact of segmentation accuracy on treatment planning for regional hyperthermia T2 - Proceedings of the 9th International Congress on Hyperthermic Oncology Y1 - 2004 ER - TY - CHAP A1 - Eulenstein, Sebastian A1 - Lange, Thomas A1 - Hünerbein, Michael A1 - Schlag, Peter A1 - Lamecker, Hans T1 - Ultrasound based navigation system incorporating preoperative planning for liver surgery T2 - Proceedings CARS Y1 - 2004 U6 - https://doi.org/10.1016/j.ics.2004.03.121 target VL - 1268 SP - 758 EP - 763 PB - Elsevier ER - TY - CHAP A1 - Lange, Thomas A1 - Tunn, Per-Ulf A1 - Lamecker, Hans A1 - Scheinemann, Peter A1 - Eulenstein, Sebastian A1 - Schlag, Peter-Michael ED - Tolxdorff, Thomas T1 - Computerunterstützte Prothesenkonstruktion mittels statistischem Formmodell bei Beckenresektion T2 - Proceedings BVM, Informatik aktuell Y1 - 2004 SP - 30 EP - 34 PB - Springer ER - TY - CHAP A1 - Lamecker, Hans A1 - Seebaß, Martin A1 - Hege, Hans-Christian A1 - Deuflhard, Peter ED - Fitzpatrick, J. ED - Sonka, Milan T1 - A 3D statistical shape model of the pelvic bone for segmentation T2 - Proceedings of SPIE - Volume 5370 Medical Imaging 2004 Y1 - 2004 U6 - https://doi.org/10.1117/12.534145 SP - 1341 EP - 1351 ER - TY - CHAP A1 - Seebaß, Martin A1 - Lamecker, Hans A1 - Lange, Thomas A1 - Gellermann, Johanna A1 - Wust, Peter T1 - A Statistical Shape Model of the Pelvic Bone for Segmentation T2 - European Society for Hyperthermic Oncology Annual Meeting Proceedings Y1 - 2003 SP - 91 EP - 92 ER - TY - CHAP A1 - Hege, Hans-Christian A1 - Schirmacher, Hartmut A1 - Westerhoff, Malte A1 - Lamecker, Hans A1 - Prohaska, Steffen A1 - Zachow, Stefan T1 - From Image Data to Three-Dimensional Models - Case Studies on the Impact of 3D Patient Models T2 - Proceedings of the Japan Korea Computer Graphics Conference 2002 Y1 - 2002 PB - Kanazawa University CY - Kanazawa City, Ishikawa, Japan ER - TY - CHAP A1 - Lamecker, Hans A1 - Lange, Thomas A1 - Seebaß, Martin T1 - A Statistical Shape Model for the Liver T2 - MICCAI 2002 Y1 - 2002 U6 - https://doi.org/10.1007/3-540-45787-9_53 SP - 422 EP - 427 PB - Springer ER - TY - JOUR A1 - Lamecker, Hans A1 - Zachow, Stefan A1 - Wittmers, Antonia A1 - Weber, Britta A1 - Hege, Hans-Christian A1 - Elsholtz, Barbara A1 - Stiller, Michael T1 - Automatic segmentation of mandibles in low-dose CT-data JF - Int. J. Computer Assisted Radiology and Surgery Y1 - 2006 VL - 1(1) SP - 393 EP - 395 ER - TY - JOUR A1 - Lamecker, Hans A1 - Zachow, Stefan A1 - Hege, Hans-Christian A1 - Zöckler, Maja T1 - Surgical treatment of craniosynostosis based on a statistical 3D-shape model JF - Int. J. Computer Assisted Radiology and Surgery Y1 - 2006 U6 - https://doi.org/10.1007/s11548-006-0024-x VL - 1(1) SP - 253 EP - 254 ER - TY - JOUR A1 - Zachow, Stefan A1 - Lamecker, Hans A1 - Elsholtz, Barbara A1 - Stiller, Michael T1 - Is the course of the mandibular nerve deducible from the shape of the mandible? JF - Int. J. of Computer Assisted Radiology and Surgery Y1 - 2006 SP - 415 EP - 417 PB - Springer ER - TY - GEN A1 - Ehlke, Moritz A1 - Ramm, Heiko A1 - Lamecker, Hans A1 - Zachow, Stefan T1 - Efficient projection and deformation of volumetric intensity models for accurate simulation of X-ray images N2 - We present an efficient GPU-based method to generate virtual X-ray images from tetrahedral meshes which are associated with attenuation values. In addition, a novel approach is proposed that performs the model deformation on the GPU. The tetrahedral grids are derived from volumetric statistical shape and intensity models (SSIMs) and describe anatomical structures. Our research targets at reconstructing 3D anatomical shapes by comparing virtual X-ray images generated using our novel approach with clinical data while varying the shape and density of the SSIM in an optimization process. We assume that a deformed SSIM adequately represents an anatomy of interest when the similarity between the virtual and the clinical X-ray image is maximized. The OpenGL implementation presented here generates accurate (virtual) X-ray images at interactive rates, thus qualifying it for its use in the reconstruction process. T3 - ZIB-Report - 12-40 KW - Digitally Reconstructed Radiograph (DRR), Anatomy Reconstruction, Statistical Shape and Intensity Model (SSIM), GPU acceleration Y1 - 2012 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-16580 SN - 1438-0064 ER - TY - GEN A1 - Ramm, Heiko A1 - Morillo Victoria, Oscar Salvador A1 - Todt, Ingo A1 - Schirmacher, Hartmut A1 - Ernst, Arneborg A1 - Zachow, Stefan A1 - Lamecker, Hans T1 - Visual Support for Positioning Hearing Implants N2 - We present a software planning tool that provides intuitive visual feedback for finding suitable positions of hearing implants in the human temporal bone. After an automatic reconstruction of the temporal bone anatomy the tool pre-positions the implant and allows the user to adjust its position interactively with simple 2D dragging and rotation operations on the bone's surface. During this procedure, visual elements like warning labels on the implant or color encoded bone density information on the bone geometry provide guidance for the determination of a suitable fit. T3 - ZIB-Report - 13-53 KW - bone anchored hearing implant KW - surgery planning KW - segmentation KW - visualization Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-42495 SN - 1438-0064 ER -