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 - CHAP A1 - Grewe, Carl Martin A1 - Zachow, Stefan T1 - Fully Automated and Highly Accurate Dense Correspondence for Facial Surfaces T2 - Computer Vision – ECCV 2016 Workshops N2 - We present a novel framework for fully automated and highly accurate determination of facial landmarks and dense correspondence, e.g. a topologically identical mesh of arbitrary resolution, across the entire surface of 3D face models. For robustness and reliability of the proposed approach, we are combining 2D landmark detectors and 3D statistical shape priors with a variational matching method. Instead of matching faces in the spatial domain only, we employ image registration to align the 2D parametrization of the facial surface to a planar template we call the Unified Facial Parameter Domain (ufpd). This allows us to simultaneously match salient photometric and geometric facial features using robust image similarity measures while reasonably constraining geometric distortion in regions with less significant features. We demonstrate the accuracy of the dense correspondence established by our framework on the BU3DFE database with 2500 facial surfaces and show, that our framework outperforms current state-of-the-art methods with respect to the fully automated location of facial landmarks. Y1 - 2016 U6 - https://doi.org/10.1007/978-3-319-48881-3_38 VL - 9914 SP - 552 EP - 568 PB - Springer International Publishing ER - TY - CHAP A1 - Grewe, Carl Martin A1 - le Roux, Gabriel A1 - Pilz, Sven-Kristofer A1 - Zachow, Stefan T1 - Spotting the Details: The Various Facets of Facial Expressions T2 - IEEE International Conference on Automatic Face and Gesture Recognition Y1 - 2018 U6 - https://doi.org/10.1109/FG.2018.00049 SP - 286 EP - 293 ER - TY - JOUR A1 - Weiss, Selina A1 - Grewe, Carl Martin A1 - Olderbak, Sally A1 - Goecke, Benjamin A1 - Kaltwasser, Laura A1 - Hildebrandt, Andrea T1 - Symmetric or not? A holistic approach to the measurement of fluctuating asymmetry from facial photographs JF - Personality and Individual Differences Y1 - 2020 U6 - https://doi.org/https://doi.org/10.1016/j.paid.2020.110137 VL - 166 SP - 1 EP - 12 ER - TY - JOUR A1 - Weiss, Selina A1 - Grewe, Carl Martin A1 - Olderbak, Sally A1 - Goecke, Benjamin A1 - Kaltwasser, Laura A1 - Hildebrandt, Andrea T1 - Symmetric or not? A holistic approach to the measurement of fluctuating asymmetry from facial photographs JF - PsyArXiv Y1 - 2020 U6 - https://doi.org/10.31234/osf.io/s534t N1 - preprint of https://doi.org/10.1016/j.paid.2020.110137 ER - TY - GEN A1 - Grewe, Carl Martin A1 - Schreiber, Lisa ED - Doll, Nikola ED - Bredekamp, Horst ED - Schäffner, Wolfgang T1 - Digital Image Archive. The Archiving and Coding of Emotions T2 - +ultra. Knowledge & Gestaltung Y1 - 2017 SP - 281 EP - 286 PB - Seemann Henschel ER - TY - GEN A1 - Grewe, Carl Martin A1 - Zachow, Stefan ED - Doll, Nikola ED - Bredekamp, Horst ED - Schäffner, Wolfgang T1 - Face to Face-Interface T2 - +ultra. Knowledge & Gestaltung Y1 - 2017 SP - 320 EP - 321 PB - Seemann Henschel ER - TY - GEN A1 - Grewe, Carl Martin A1 - Le Roux, Gabriel A1 - Pilz, Sven-Kristofer A1 - Zachow, Stefan T1 - Spotting the Details: The Various Facets of Facial Expressions N2 - 3D Morphable Models (MM) are a popular tool for analysis and synthesis of facial expressions. They represent plausible variations in facial shape and appearance within a low-dimensional parameter space. Fitted to a face scan, the model's parameters compactly encode its expression patterns. This expression code can be used, for instance, as a feature in automatic facial expression recognition. For accurate classification, an MM that can adequately represent the various characteristic facets and variants of each expression is necessary. Currently available MMs are limited in the diversity of expression patterns. We present a novel high-quality Facial Expression Morphable Model built from a large-scale face database as a tool for expression analysis and synthesis. Establishment of accurate dense correspondence, up to finest skin features, enables a detailed statistical analysis of facial expressions. Various characteristic shape patterns are identified for each expression. The results of our analysis give rise to a new facial expression code. We demonstrate the advantages of such a code for the automatic recognition of expressions, and compare the accuracy of our classifier to state-of-the-art. T3 - ZIB-Report - 18-06 Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:0297-zib-67696 SN - 1438-0064 ER - TY - GEN A1 - Grewe, Carl Martin A1 - Lamecker, Hans A1 - Zachow, Stefan ED - Hermanussen, Michael T1 - Landmark-based Statistical Shape Analysis T2 - Auxology - Studying Human Growth and Development url Y1 - 2013 UR - http://www.schweizerbart.de/publications/detail/isbn/9783510652785 SP - 199 EP - 201 PB - Schweizerbart Verlag, Stuttgart ER - TY - GEN A1 - Grewe, Carl Martin A1 - Lamecker, Hans A1 - Zachow, Stefan T1 - Digital morphometry: The Potential of Statistical Shape Models T2 - Anthropologischer Anzeiger. Journal of Biological and Clinical Anthropology Y1 - 2011 SP - 506 EP - 506 ER - TY - THES A1 - Auch, Simón T1 - Realtime Action Unit detection Y1 - 2016 ER -