Research in Reconstruction

Table of Content

Abstract
Contact Person and Group Coordination
Research Projects in Reconstruction
Related Publications
Working Group

Contact Person and Group Coordination


Tobias Lasser	Nassir Navab

Research Projects in Reconstruction

Estimation of Flow Parameters from X-ray Data

This project focuses on the quantification of blood flow based on 2D and 3D angiographic X-ray image data, which is of particular interest during minimally invasive interventional procedures such as recanalizations of stenotic vessels and embolizations of arteries that feed tumors or vascular malformations in the patient's brain, for example. Our projects cover the evaluation of model-based approaches involving CFD (computational fluid dynamics) simulations as well as methods that aim at estimating the optical flow in the images and deriving quantitative blood flow information from these results.

Learning and Understanding in 3D Point Clouds

Point offer are a unified representation for 3D data. Whether the sensor is a laser scanner, lidar or a depth camera, the acquired information can be stored in form an unstructured point cloud. This makes such representation ubiquitous. In this project, we aim to adapt state-of-the-art learning algorithms to efficiently handle point cloud data in order to find objects, detect structures, perform segmentation and 3d reconstruction.

patient-Specific Translational research on Atherosclerosis and Diagnosis (STAnD)

Multispectral Reconstruction

Multispectral imaging is an emerging modality for use in dermatological diagnosis which has the potential to offer quantitative measurements of the skin tissue, thus providing a more accurate diagnosis tool for a wide range of afflictions. Multispectral images are sequences of images taken at different wavelengths and due to their improved spectral discrimination, can offer insight into the distribution of collagen, melanin, and hemoglobin within skin lesions.
The main motivation of this project is to provide dermatologists with a multispectral imaging system that allows quantification of skin lesions as well as tracking of disease progression in an automated fashion. To this end, both multispectral images are being acquired provide quantitative metrics of the skin, as well the size and geometry of the lesions.

Stereo Time-of-Flight

This paper describes a novel method to acquire depth images based on combining a pair of ToF^? (Time of Flight) cameras. As opposed to approaches that register point clouds posterior to the image acquisition, we propose to combine the measurements of the two cameras at the acquisition level. To do so, we actively control the infrared lighting of the scene such that the two cameras emit and measure the reflected infrared light first one after the other, and then simultaneously. Assuming the scene is static during these three stages and gathering the obtained depth measurements in each state, we derive a set of constraints that allow us to optimize the two depth images. In terms of hardware requirements, the cameras need to have access to the control of the infrared lights and should work with the same infrared wavelength and with exactly the same modulation frequency. A quantitative evaluation of the performance of the proposed method for different objects and setups is provided based on a simulation of the ToF^? cameras. Results on real images are also provided. In both simulation and real images the stereo-ToF acquisition is able to produce more accurate depth measurements.

Scene Understanding From a Moving Camera

Modern vehicles are equipped with multiple cameras which are already used in various practical applications. Advanced driver assistance systems (ADAS) are of particular interest because of the safety and comfort features they offer to the driver. Camera based scene understanding is an important scientific problem that has to be addressed in order to provide the information needed for camera based driver assistance systems. While frontal cameras are widely used, there are applications where cameras observing lateral space can deliver better results. Fish eye cameras mounted in the side mirrors are particularly interesting, because they can observe a big area on the side of the vehicle and can be used for several applications for which the traditional front facing cameras are not suitable.

We present a general method for scene understanding using 3D reconstruction of the environment around the vehicle. It is based on pixel-wise image labeling using a conditional random field (CRF). Our method is able to create a simple 3D model of the scene and also to provide semantic labels of the different objects and areas in the image, like for example cars, sidewalks, and buildings.

We demonstrate how our method can be used for two applications that are of high importance for various driver assistance systems - car detection and free space estimation. We show that our system is able to perform in real time for speeds of up to 63 km/h.

Cardiac C-Arm CT

Tomographic reconstruction from rotational cone-beam X-ray data is only solved for static objects of interest (like the abdominal region). In cardiac imaging, a rotational angiography sequence takes about 4 to 6s and therefore spans several heart beats. Since such an acquisition scheme forces a trade-off between consistency of the scene and reasonable baselines between camera positions, standard reconstruction techniques fail at recovering the 3D+t scene. We propose a new reconstruction framework based on variational level sets including a new data term for symbolic reconstruction as well as a novel incorporation of motion into the level set formalism. The resulting simultaneous estimation of shape and motion proves feasible in first experiments.

Deformable Semantic SLAM

In the scope of this project we are interested in creating a dataset for deformable, semantic SLAM. The goal is to recognize, segment and reconstruct different object categories in real, indoor environments. The focus is live, dynamic objects, such as people and animals. Still, to this date, accurate segmentation in real-time of deformable surfaces is a challenging problem.

Advanced Robotics for Multi-Modal Interventional Imaging (RoBildOR)

This project aims at developing advanced methods for robotic image acquisitions, enabling more flexible, patient- and process-specific functional and anatomical imaging with the operating theater. Using robotic manipulations, co-registered and dynamic imaging can be provided to the surgeon, allowing for optimal implementation of preoperative planning. In particular, this projects is the first one developing concepts for intraoperative SPECT-CT, and introduces intraoperative robotic Ultrasound imaging based on CT trajectory planning, enabling registration with angiographic data. With distinguished partners from Bavarian industry, this project has a fundamental contribution in developing safe, reliable, flexible, and multi-modal imaging technologies for the operating room of the future.

Reconstruction and Registration of Histology and Phase Contrast Images for Clinical Validation of Imaging Modalities

Before its introduction into the hospital, a new imaging modality has to be validated. In other words, appearing structures need to be correlated to the imaged tissues. Such a cross validation is only meaningful when performed against the gold standard which is histology. Currently, cross validation is performed by qualitative comparison of 3D datasets to 2D histology slices. Since the acquisition of a consistent 3D histology volume is a challenging task, its comparison to the corresponding dataset always remained qualitative.

The classic histology procedure can be divided in four steps: pre processing, cutting, post processing and imaging of the tissues. In the first step, the sample is chemically processed to preserve the tissues and is then embedded in a paraffin block. By using a microtome, it is cut in very thin slices, and put on a glass slide. During post processing the sample is stained to enhance the structures of interest. The imaging is performed with a camera mounted in a microscope, or with a dedicated scanner. Several difficulties inherent to this process can have a dramatic influence on the quality of the reconstructed histology volume. For instance, since the cutting process is done manually, problems like flipping, bending or ripping of the slides may happen. If the knife starts to wear off, some banding will appear over the slices. Moreover, a few slices could be missing. Finally since the staining color is time dependent, variation in the color of the slices can occur.

In this project, we propose to improve the histology procedure and to develop methods towards a consistent reconstruction of 3D histology volumes.

Developing Image Processing Techniques for Cryo Electron Tomography

Cryo-ET has recently emerged as a leading technique to investigate the three-dimensional(3D) structure of biological specimens at close-to-native state. It also bridges the gap between low-resolution imaging techniques (e.g. light microscopy) and high-resolution techniques (e.g. single particle electron microscopy). The technique consists of acquiring many two-dimensional (2D) projections of the structure under scrutiny at various tilt angles under cryogenic conditions. The 3D structure is recovered through a number of steps including projection alignment, reconstruction and de-nosing. The resolution of the reconstructed tomogram, however, is aaffected by the low signal to noise ratio (SNR) of the projection images (typically 0.1 to 0.01) and the limited angular coverage (typically 60 to 70 ) resulting in wedge-shaped missing information in Fourier space, the so-called missing wedge; making the reconstruction process very challenging and demanding.

SUPRA: Software Defined Ultrasound Processing for Real-Time Applications

SUPRA is an open-source pipeline for fully software defined ultrasound processing for real-time applications. Covering everything from beamforming to output of B-Mode images, SUPRA can help to improve the reproducibility of results and does allow for a full customization of the image acquisition workflow. Including all processing stages of a common ultrasound pipeline, it can be executed in 2D and 3D on consumer GPUs in real-time. Even on hardware as small as the CUDA enabled Jetson TX2, SUPRA allows for 2D imaging in real-time.

You can access the code on our github page: https://github.com/IFL-CAMP/supra
Additional information can be found in our work on SUPRA
Göbl, R. and Navab, N. and Hennersperger, C., SUPRA: Open Source Software Defined Ultrasound Processing for Real-Time Applications, eprint arXiv:1711.06127, Nov 2017, under review for IPCAI2018 The development of SUPRA was partly funded by the European Horizon 2020 Project EDEN2020.

Intra-operative Imaging and Navigation for Minimal Invasiveness in Head and Neck Cancer

Intra-operative Imaging and Navigation for Guidance in Neurosurgical Procedures

Deformable Guide Wire Tracking

These days, X-ray fluoroscopic imaging is the modality used most widely to guide physicians in angiographic interventions. Current guidance procedures are based on a roadmap, e.g. a digital subtracted angiography (DSA) acquired from a fixed viewpoint and the injection of contrast agent to visualize the current vessel anatomy. Such roadmaps cannot directly be blended with the fluoroscopic sequence due to misalignment caused by respiratory motion. A fundamental step toward a successful integration of any navigation application into clinical routine is the estimation and compensation of respiratory motion. We propose a novel method for deformable tracking of multiple ridge segments based on a MAP-MRF formulation and efficient discrete optimization. Ridges are modeled as B-Spline curves which allows us to apply smooth deformations based on a minimal number of parameters. Our tracking framework is well adapted to the noisy domain of fluoroscopic imaging and the handling of multiple segments.

Stereo Vision

This project focuses on the development of novel methods for efficient or accurate binocular stereo vision.

Assessment of Knee Cartilage

Degeneration of knee joint cartilage is an important and early indicator of osteoarthritis (OA) which is one of the major socio-economic burdens nowadays. Accurate quantification of the articular cartilage degeneration in an early stage using MR images is a promising approach in diagnosis and therapy for this disease. Particularly, volume and thickness measurement of cartilage tissue has been shown to deliver significant parameters in assessment of pathologies. Here, accurate computer-aided diagnosis tools could improve the clinical routine where image segmentation plays a crucial role. In order to overcome the time-consuming and tedious work of manual segmentation, one tries to automate the segmentation as much as possible. We focus on novel atlas-based segmentation methods for knee cartilage as well as improve today’s clinical routine of manual segmentation methods. In addition, we try to evaluate different methods for the assessment of parameters such as volume and thickness which could allow computer-aided diagnosis of knee cartilage pathologies in an early stage.

Endoscopic Video Processing

The diagnosis and surveillance of several gastrointestinal (GI) diseases such as colateral or oesaphageal cancer are performed under endoscopic guidance. However, currently there exists no computer aided navigation tool to support these procedures. The goal of this project is to provide an advanced visualisation and automatic recognition tool in order to support the navigation and targeting in GI endoscopic procedures. The aim of the project is twofold: reconstructing the organ surface from endoscopic videos using monoSLAM and automatically recognising the biopsy locations to support the navigation and targeting in endoscopy.

Related Publications

2020
	M. Slavcheva, M. Baust, S. Ilic Variational Level Set Evolution for Non-rigid 3D Reconstruction from a Single Depth Camera IEEE Transactions on Pattern Analysis and Machine Intelligence (PAMI). The final publication is available at ieeexplore.ieee.org. (supplementary) (bib)
2019
	Y. Zhao, T. Birdal, H. Deng, F. Tombari 3D Point-Capsule Networks IEEE Computer Vision and Pattern Recognition (CVPR), Long Beach, United States, June 2019 (bib)
	T. Birdal, U. Simsekli Probabilistic Permutation Synchronization using the Riemannian Structure of the Birkhoff Polytope IEEE Computer Vision and Pattern Recognition (CVPR), Long Beach, United States, June 2019 [oral] (bib)
	H. Deng, T. Birdal, S. Ilic 3D Local Features for Direct Pairwise Registration IEEE Computer Vision and Pattern Recognition (CVPR), Long Beach, United States, June 2019 (bib)
	T. Lasser, M. Hornung, D. Frank elsa - an elegant framework for tomographic reconstruction International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Philadelphia, USA, June 2019 (bib)
	T. Cheslerean-Boghiu, F. Pfeiffer, T. Lasser Task-driven Acquisition in Anisotropic X-ray Dark-Field Tomography International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Philadelphia, USA, June 2019 (bib)
	A. Maier, C. Syben, T. Lasser, C. Riess A gentle introduction to deep learning in medical image processing Zeitschrift für medizinische Physik 29(2):86-101, 2019 (bib)
	W. Simson, R. Göbl, M. Paschali, M. Krönke, K. Scheidhauer, S. Weber, N. Navab End-to-End Learning-Based Ultrasound Reconstruction The first two authors contributed equally. The original manuscript is available currently online on arXiv. (bib)
	T. Birdal, B. Busam, N. Navab, S. Ilic, P. Sturm Generic Primitive Detection in Point Clouds Using Novel Minimal Quadric Fits IEEE Transactions on Pattern Analysis and Machine Intelligence (T-PAMI), 2019 (bib)
2018
	T. Birdal, U. Simsekli, M. O. Eken, S. Ilic Bayesian Pose Graph Optimization via Bingham Distributions and Tempered Geodesic MCMC Advances in Neural Information Processing Systems Conference (NIPS), Montréal, Quebec, Canada 2018 (poster) (supplementary) (bib)
	M. Wieczorek, F. Schaff, C. Jud, D. Pfeiffer, F. Pfeiffer, T. Lasser Brain Connectivity Exposed by Anisotropic X-ray Dark-field Tomography Sci. Rep. 8:14345, 2018 (bib)
	H. Deng, T. Birdal, S. Ilic PPF-FoldNet: Unsupervised Learning of Rotation Invariant 3D Local Descriptors European Conference On Computer Vision (ECCV), Munich, Germany, September 2018 (bib)
	A. Haarbach, T. Birdal, S. Ilic Survey of Higher Order Rigid Body Motion Interpolation Methods for Keyframe Animation and Continuous-Time Trajectory Estimation International Conference on 3D Vision (3DV), Verona, Italy, September 2018 [spotlight] (bib)
	T. Birdal, B. Busam, N. Navab, S. Ilic, P. Sturm A Minimalist Approach to Type-Agnostic Detection of Quadrics in Point Clouds IEEE Computer Vision and Pattern Recognition (CVPR), Salt Lake City, United States, June 2018 (bib)
	H. Deng, T. Birdal, S. Ilic PPFNet: Global Context Aware Local Features for Robust 3D Point Matching IEEE Computer Vision and Pattern Recognition (CVPR), Salt Lake City, United States, June 2018 [spotlight] (bib)
	T. Cheslerean-Boghiu, Y. Sharma, F. Pfeiffer, T. Lasser Detectability Indices in Anisotropic X-ray Dark-field Tomography International Conference on Image Formation in X-Ray Computed Tomography, Salt Lake City, USA, May 2018 (bib)
	S. Seyyedi, E. Liapi, T. Lasser, R. Ivkov, R. Hatwar, J. W. Stayman Low-Dose CT Perfusion of the Liver Using Reconstruction of Difference IEEE Transactions on Radiation and Plasma Medical Sciences 2(3):205-214, 2018 (bib)
	Y. Sharma, S. Bachche, M. Kageyama, , F. Pfeiffer, T. Lasser, A. Momose Trochoidal X-ray Vector Radiography: Directional dark-field without grating stepping Appl. Phys. Lett. 112, 111902 (2018); http://dx.doi.org/10.1063/1.5020361 (bib)
	S. Nitkunanantharajah, C. Hennersperger, X.L. Dean-Ben, D. Razansky, N. Navab Trackerless panoramic optoacoustic imaging: a first feasibility evaluation International Journal of Computer Assisted Radiology and Surgery / 9th International Conference on Information Processing in Computer-Assisted Interventions (IPCAI), Berlin, Germany, June 2018. The original publication is available online at springer.com (bib)
	Y. Sharma, S. Bachche, M. Kageyama, M. Kuribayashi, F. Pfeiffer, T. Lasser, A. Momose Trochoidal X-ray Vector Radiography (TXVR): Directional Dark-field Without Grating Stepping International Symposium on BioMedical Applications of X-Ray Phase Contrast Imaging (IMXP), Garmisch-Patenkirchen, Germany, January 2018 (bib)
	S. Seyyedi, M. Wieczorek, F. Pfeiffer, T. Lasser Incorporating a Noise Reduction Technique into X-ray Tensor Tomography IEEE Transactions on Computational Imaging 4(1):137-146, 2018 (bib)
2017
	M. Slavcheva, W. Kehl, N. Navab, S. Ilic SDF-2-SDF Registration for Real-time 3D Reconstruction from RGB-D Data International Journal of Computer Vision (IJCV), Springer Verlag. The final publication is available at www.springerlink.com. (bib)
	T. Birdal, S. Ilic CAD Priors for Accurate and Flexible Instance Reconstruction International Conference on Computer Vision (ICCV), Venice, Italy, October 2017 (bib)
	P. Symvoulidis, A. Lauri, A. Stefanoiu, M. Cappetta, S. Schneider, H. Jia, A. Stelzl, M. Koch, C. Cruz Perez, A. Myklatun, S. Renninger, A. Chmyrov, T. Lasser, W. Wurst, V. Ntziachristos, G. Westmeyer NeuBtracker - imaging neurobehavioral dynamics in freely behaving fish Nature Methods 14, 1079-1082, 2017 (bib)
	S. Seyyedi, E. Liapi, T. Lasser, R. Ivkov, R. Hatwar, J. W. Stayman Evaluation of Low-Dose CT Perfusion for the Liver using Reconstruction of Difference International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Xi'an Shaanxi, China, June 2017 (bib)
	M. Wieczorek, F. Pfeiffer, T. Lasser Micro-structure orientation extraction for Anisotropic X-Ray Dark-Field Tomography International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Xi'an Shaanxi, China, June 2017 (bib)
	Y. Sharma, F. Schaff, M. Wieczorek, F. Pfeiffer, T. Lasser Acquisition Schemes for Directional Dark-Field Tomographic Modalities International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Xi'an Shaanxi, China, June 2017 (bib)
	N. Schilling, M. Wieczorek, T. Lasser Statistical Models for Anisotropic X-Ray Dark-field Tomography International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Xi'an Shaanxi, China, June 2017 (bib)
	Y. Sharma, F. Schaff, M. Wieczorek, F. Pfeiffer, T. Lasser Design of Acquisition Schemes and Setup Geometry for Anisotropic X-ray Dark-Field Tomography (AXDT) Scientific Reports 7:3195, 2017. (bib)
	C. Ulas, PA. Gómez, JI. Sperl, C. Preibisch, MI. Menzel, A. Haase, B. Menze A Robust Reconstruction Method for Quantitative Perfusion MRI: Application to Brain Dynamic Susceptibility Contrast (DSC) Imaging Proceedings of the International Society of Magnetic Resonance in Medicine (ISMRM), Hawaii, USA, April 2017 (bib)
2016
	J. Gardiazabal, P. Matthies, J. Vogel, B. Frisch, N. Navab, S. I. Ziegler, T. Lasser Flexible Mini Gamma Camera Reconstructions of Extended Sources using Step and Shoot and List Mode Medical Physics 43(12):6418-6428, 2016. (bib)
	M. Wieczorek, F. Schaff, F. Pfeiffer, T. Lasser Anisotropic X-Ray Dark-Field Tomography: A Continuous Model and its Discretization Phys. Rev. Lett. 117, 158101, 2016 (bib)
	Y. Sharma, M. Wieczorek, F. Schaff, S. Seyyedi, F. Prade, F. Pfeiffer, T. Lasser Six dimensional X-ray Tensor Tomography with a compact laboratory setup Appl. Phys. Lett. 109, 134102 (2016); http://dx.doi.org/10.1063/1.4963649 (bib)
	S. Seyyedi, M. Wieczorek, C. Jud, F. Pfeiffer, T. Lasser A Regularized X-ray Tensor Tomography Reconstruction Technique International Conference on Image Formation in X-Ray Computed Tomography, Bamberg, Germany, July 2016 (bib)
	M. Wieczorek, C. Jud, F. Schaff, F. Pfeiffer, T. Lasser X-ray tensor tomography -- linear system approach to reconstruction International Conference on Image Formation in X-Ray Computed Tomography, Bamberg, Germany, July 2016 (bib)
	Y. Sharma, M. Wieczorek, C. Jud, F. Schaff, F. Pfeiffer, T. Lasser X-ray Tensor Tomography: How much to measure? International Conference on Image Formation in X-Ray Computed Tomography, Bamberg, Germany, July 2016 (bib)
	C. Ulas, PA. Gómez, JI. Sperl, C. Preibisch, B. Menze Spatio-temporal MRI Reconstruction by Enforcing Local and Global Regularity via Dynamic Total Variation and Nuclear Norm Minimization Proceedings of International Symposium on Biomedical Imaging (ISBI), April 2016 (bib)
	S. Seyyedi, M. Wieczorek, Y. Sharma, F. Schaff, C. Jud, F. Pfeiffer, T. Lasser Component-based TV Regularization for X-ray Tensor Tomography International Symposium on Biomedical Imaging (ISBI), Prague, Czech Republic, April 2016 (bib)
	A. Fischer, T. Lasser, M. Schrapp, J. Stephan, P. B. Noël Object Specific Trajectory Optimization for Industrial X-ray Computed Tomography Scientific Reports 6:19135, 2016 (bib)
	M. Wieczorek, F. Schaff, C. Jud, F. Pfeiffer, T. Lasser An optimization oriented approach to X-ray tensor tomogprahy International Symposium on BioMedical Applications of X-Ray Phase Contrast Imaging (IMXP), Garmisch-Patenkirchen, Germany, January 2016 (bib)
	Y. Sharma, M. Wieczorek, F. Schaff, C. Jud, F. Pfeiffer, T. Lasser Acquisition Geometry for X-ray Tensor Tomography International Symposium on BioMedical Applications of X-Ray Phase Contrast Imaging (IMXP), Garmisch-Patenkirchen, Germany, January 2016 (bib)
	C. Bluemel, P. Matthies, K. Herrmann, S. P. Povoski 3D Scintigraphic Imaging and Navigation in Radioguided Surgery: Freehand SPECT Technology and its Clinical Applications Expert Review of Medical Devices, 2016 (bib)
2015
	P. Matthies, B. Frisch, J. Vogel, T. Lasser, M. Friebe, N. Navab Inside-Out Tracking for Flexible Hand-held Nuclear Tomographic Imaging IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego, USA, November 2015 (bib)
	J. Gardiazabal, B. Frisch, P. Matthies, J. Vogel, S. I. Ziegler, N. Navab, T. Lasser List-Mode Reconstruction for Continuous Freehand SPECT Acquisitions IEEE Nuclear Science Symposium and Medical Imaging Conference, San Diego, USA, November 2015 (bib)
	C. Hennersperger, M. Baust, D. Mateus, N. Navab Computational Sonography MICCAI 2015, the 18th International Conference on Medical Image Computing and Computer Assisted Intervention (bib)
	K. Sch{\"o}rner, A. Fischer, T. Lasser, M. Schrapp, J. Stephan, P. B. Noël CT Reconstruction with Object Specific Non-Standard Trajectories Intl. Symposium on Digital Industrial Radiology and Computed Tomography (DIR 2015), Ghent, Belgium, June 2015 (bib)
	J. Vogel, F. Schaff, A. Fehringer, C. Jud, M. Wieczorek, F. Pfeiffer, T. Lasser Constrained X-ray tensor tomography reconstruction Optics Express 23(12):15134-15151, 2015 (bib)
	M. Wieczorek, J. Vogel, A. Weinmann, C. Jud, F. Schaff, M. Storath, F. Pfeiffer, M. Baust, T. Lasser Total Variation Regularization for X-Ray Tensor Tomography Proceedings of Fully3D, Newport, USA, June 2015 (bib)
	J. Vogel, M. Wieczorek, C. Jud, F. Schaff, F. Pfeiffer, T. Lasser X-ray Tensor Tomography Reconstruction Proceedings of Fully3D, Newport, USA, June 2015 (bib)
	J. Gardiazabal, J. Vogel, P. Matthies, M. Wieczorek, B. Frisch, N. Navab, S. I. Ziegler, T. Lasser Fully 3D thyroid imaging with mini gamma cameras Proceedings of Fully3D, Newport, USA, June 2015 (bib)
	M. Wieczorek, J. Frikel, J. Vogel, E. Eggl, F. Kopp, P. B. Noël, F. Pfeiffer, L. Demaret, T. Lasser X-ray Computed Tomography using Curvelet Sparse Regularization Medical Physics 42(4):1555, 2015 (bib)
	T. Lasser, J. Gardiazabal, M. Wieczorek, P. Matthies, J. Vogel, B. Frisch, N. Navab Towards 3D thyroid imaging using robotic mini gamma cameras Bildverarbeitung für die Medizin, Lübeck, Germany, March 2015 (bib)
	A. Hartl, D. I. Shakir, T. Lasser, S. I. Ziegler, N. Navab Detection models for freehand SPECT reconstruction Physics in Medicine and Biology 60(3):1031-1046, 2015 (bib)
2014
	O. Zettinig, C. Hennersperger, C. Schulte-zu-Berge, M. Baust, N. Navab 3D Velocity Field and Flow Profile Reconstruction from Arbitrarily Sampled Doppler Ultrasound Data Proceedings of the 17th International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI), Boston, USA, September 2014. The original publication is available online at link.springer.com (bib)
	M. Müller, L.E.S. Helljesen, R. Prevost, I. Viola, K. Nylund, O.H. Gilja, N. Navab, W. Wein Deriving Anatomical Context from 4D Ultrasound Eurographics Workshop on Visual Computing for Biology and Medicine (VCBM), September 3-5 2014, Vienna, Austria (bib)
	A. Okur, R. Voigt, R. Stauder, N. Navab Investigation of performance log files of freehand SPECT acquisitions for usage characteristics and surgical phase determination The 7th Hamlyn Symposium on Medical Robotics, London, UK, July 2014 (bib)
	P. Matthies, J. Gardiazabal, A. Okur, T. Lasser, N. Navab Accuracy evaluation of interventional nuclear tomographic reconstruction using mini gamma cameras The 7th Hamlyn Symposium on Medical Robotics, London, UK, July 2014 (bib)
	P. Matthies, J. Gardiazabal, A. Okur, J. Vogel, T. Lasser, N. Navab Mini Gamma Cameras for Intra-operative Nuclear Tomographic Reconstruction Medical Image Analysis 18(8):1329-1336, 2014 (bib)
	A. Fehringer, T. Lasser, I. Zanette, P. B. Noël, F. Pfeiffer A versatile tomographic forward- and back-projection approach on multi-GPUs Proceedings of SPIE 9034, 90344F (2014) (bib)
	M. Wieczorek, J. Vogel, T. Lasser CampRecon - a software framework for linear inverse problems Technical report, Technische Universität München, 2014. Available via mediatum. (bib)
	A. Malecki, G. Potdevin, T. Biernath, E. Eggl, K. Willer, T. Lasser, J. Maisenbacher, J. Gibmeier, A. Wanner, F. Pfeiffer X-Ray Tensor Tomography Europhysics Letters 105(3):38002, 2014. (bib)
2013
	P. Matthies, K. Sharma, A. Okur, J. Gardiazabal, J. Vogel, T. Lasser, N. Navab First use of mini gamma cameras for intra-operative robotic SPECT reconstruction Proceedings of the 16th International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI), Nagoya, Japan, September 2013 (bib)
	P. Matthies, A. Okur, T. Wendler, N. Navab, M. Friebe Combination of intra-operative freehand SPECT imaging with MR images for guidance and navigation IEEE Engineering in Medicine and Biology (EMBC), Osaka, Japan, July 2013. (bib)
	A. Malecki, G. Potdevin, T. Biernath, E. Eggl, T. Lasser, J. Maisenbacher, J. Gibmeier, A. Wanner, F. Pfeiffer Directional X-Ray Scattering Tomography Proceedings of Fully3D, Lake Tahoe, USA, June 2013 (bib)
	W. Wein, A. Ladikos Towards General Motion Recovery in Cone-Beam Computed Tomography 12th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine, June 16-21 2013, Lake Tahoe, CA USA (bib)
	M. Wieczorek, J. Frikel, J. Vogel, F. Pfeiffer, L. Demaret, T. Lasser Curvelet sparse regularization for differential phase-contrast X-ray imaging Proceedings of Fully3D, Lake Tahoe, USA, June 2013. (bib)
	J. Vogel, T. Lasser, J. Gardiazabal, N. Navab Trajectory optimization for intra-operative nuclear tomographic imaging Medical Image Analysis 17(7):723-731, 2013. (bib)
	A. Okur, D. I. Shakir, P. Matthies, A. Hartl, M. Essler, S. I. Ziegler, T. Lasser, N. Navab Freehand Tomographic Nuclear Imaging Using Tracked High-Energy Gamma Probes Bildverarbeitung für die Medizin 2013 (BVM), Heidelberg, Germany, March 2013. The original publication is available online at www.springerlink.com (bib)
2012
	X. Cheng, J. Liu, J. Vogel, Z. Liu, N. Navab, S. I. Ziegler, K. Shi Time-Activity Curve based Sinogram Decomposition for Streak Artifacts Reduction in Dynamic PET Reconstruction Proceedings of the IEEE 2012 Medical Imaging Conference, Anaheim, California, USA, October 2012 (bib)
	J. Vogel, T. Reichl, J. Gardiazabal, N. Navab, T. Lasser Optimization of Acquisition Geometry for Intra-operative Tomographic Imaging Proceedings of the 15th International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI), Nice, France, October 2012 (bib)
	D. I. Shakir, A. Okur, A. Hartl, P. Matthies, M. Essler, S. I. Ziegler, T. Lasser, N. Navab Towards Intra-operative PET for Head and Neck Cancer: Lymph Node Localization Using High-energy Probes Proceedings of the 15th International Conference on Medical Image Computing and Computer Assisted Interventions (MICCAI), Nice, France, October 2012 (bib)
	A. Karamalis, W. Wein, T. Klein, N. Navab Ultrasound Confidence Maps using Random Walks Medical Image Analysis, 16, 6, 1101 - 1112, 2012, DOI: http://dx.doi.org/10.1016/j.media.2012.07.005 (bib)
	S. Abdurahman, A. Jerebko, T. Mertelmeier, T. Lasser, N. Navab Out-of-plane artifact reduction in tomosynthesis based on regression modeling and outlier detection 11th Intl. Workshop on Breast Imaging (IWDM 2012), Philadelphia, USA, July 2012 (bib)
	A. Hartl, D. I. Shakir, R. Kojchev, N. Navab, S. I. Ziegler, T. Lasser Freehand SPECT reconstructions using look up tables SPIE Medical Imaging Conference, February 4 - February 9 2012, San Diego, USA (bib)
	D. I. Shakir, A. Hartl, F. R. Schneider, J. Pulko, S. I. Ziegler, N. Navab, T. Lasser Two new ad-hoc models of detection physics and their evaluation for navigated beta probe surface imaging Proceedings of SPIE Visualization, Image-Guided Procedures, and Modeling Conference, San Diego, CA, USA, February 2012 (bib)
2011
	J.-H. Choi, A. Maier, A. Keil, R. Fahrig Acquisition of 3D Knee Geometry under Weight-Bearing Conditions using a C-Arm CT Scanner RSNA, Chicago, IL, U.S.A., November 2011 (bib)
	A. Hartl, T. Lasser, N. Navab, S. I. Ziegler Impact of acquisition geometry and physical model on Freehand SPECT reconstructions IEEE Medical Imaging Conference, October 23 - October 29 2011, Valencia, Spain (bib)
	D. I. Shakir, T. Lasser, A. Drzezga, S. I. Ziegler, N. Navab Evaluation of Navigated Beta-Probe Surface Imaging on a Realistic 3D Phantom Proceedings of the IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS-MIC), Valencia, Spain, October 2011 (bib)
	W. Wein, A. Ladikos Detecting Patient Motion in Projection Space for Cone-beam Computed Tomography Medical Image Computing and Computer-Assisted Intervention (MICCAI 2011), Toronto, Canada, September 2011 (bib)
	W. Wein, A. Ladikos, A. Baumgartner Self-calibration of geometric and radiometric parameters for cone-beam computed tomography 11th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine, July 11-15 2011, Potsdam, Germany. (bib)
	A. Malecki, T. Biernath, M. Bech, T. Lasser, G. Potdevin, F. Pfeiffer Towards the Reconstruction of 3D Orientation Information from Direction-Sensitive X-Ray Projections Proceedings of Fully3D, Potsdam, Germany, June 2011 (bib)
	B. Diotte, C. Cagniart, S. Ilic Markerless Motion Capture in the Operating Room. Technical Report, Technische Universität München, München, Germany, Mai 2011 (bib)
	D. I. Shakir, A. Hartl, N. Navab, S. I. Ziegler Evaluation of an ad hoc model of detection physics for navigated beta-probe surface imaging Proceedings of SPIE Visualization, Image-Guided Procedures, and Modeling Conference, Lake Buena Vista (Orlando Area), FL, USA, February 2011 (bib)
	T. Lasser, S. I. Ziegler, N. Navab Freehand SPECT in low uptake situations Proceedings of SPIE 7961, 79611Z, 2011 (bib)
	A. Maier, J.-H. Choi, A. Keil, C. Niebler, M. Sarmiento, A. Fieselmann, G. Gold, S. Delp, R. Fahrig Analysis of Vertical and Horizontal Circular C-Arm Trajectories SPIE Medical Imaging, San Diego, CA, U.S.A., Feburary 2011 (bib)
2010
	D. I. Shakir, N. Navab, S. I. Ziegler Acquisition Model for Iterative Reconstruction of Navigated Beta-Probe Surface Images Proceedings of the IEEE Nuclear Science Symposium and Medical Imaging Conference (NSS-MIC), Knoxville, TN, USA, November 2010 (bib)
	D. I. Shakir, J. Bieniarz, S. Pirsig, T. Wendler, N. Navab, S. I. Ziegler A first study on biological feasibility of intraoperative control of tumor resection borders with navigated beta-probe surface imaging Proceedings of the Annual Meeting of the Society of Nuclear Medicine (SNM), Salt Lake City, UT, USA, June 2010 (bib)
	A. Plate, A. Ahmadi, T. Klein, N. Navab, J. Weiße, J. Mehrkens, K. Bötzel Towards a More Objective Visualization of the Midbrain and its Surroundings Using 3D Transcranial Ultrasound 54. Jahrestagung der Deutschen Gesellschaft für Klinische Neurophysiologie und Funktionelle Bildgebung (DGKN), Halle, GER, March 2010 (bib)
	C. Rohkohl, G. Lauritsch, A. Keil, J. Hornegger CAVAREV--an open platform for evaluating 3D and 4D cardiac vasculature reconstruction Physics in Medicine and Biology, vol. 55, no. 10, pp. 2905-2915, 2010 (bib)
	M. Blume, A. Martinez-Möller, A. Keil, N. Navab, M. Rafecas Joint Reconstruction of Image and Motion in Gated Positron Emission Tomography IEEE Trans. Med. Imag., vol. 29, no. 11, pp. 1892-1906, November 2010 (bib)
	M. Blume, A. Keil, N. Navab, M. Rafecas Joint Reconstruction of Image and Motion for PET: Displacement Fields Versus a B-Spline Motion Model Proc. IEEE Nuclear Science Symposium and Medical Imaging Conference, Knoxville, TN, U.S.A., October 2010 (bib)
	M. Blume, M. Rafecas Joint Reconstruction of Image and Motion for PET Using Linear Diffusion Regularization Congreso Anual de la Sociedad Espa\~nola de Ingenier\'ia Biom\'edica, Madrid, Spain, November 2010 (bib)
2009
	T. Wendler, K. Herrmann, A. Schnelzer, T. Lasser, J. Traub, O. Kutter, T. Schuster, M. Kiechle, M. Schwaiger, N. Navab, S. I. Ziegler, A. K. Buck Clinical introduction of freehand SPECT for image-guided sentinel lymph node biopsy Proceedings of Annual Congress of the European Association of of Nuclear Medicine (EANM 2009), Barcelona, Spain, October 2009 (bib)
	T. Wendler, X. Feng, K. Herrmann, T. Lasser, J. Traub, S. I. Ziegler, N. Navab, A. K. Buck 2D/3D registration of freehand SPECT and planar scintigraphy for clinical evaluation of 3D thyroid scintigraphy Proceedings of Annual Congress of the European Association of of Nuclear Medicine (EANM 2009), Barcelona, Spain, October 2009 (bib)
	T. Wendler, K. Herrmann, T. Lasser, J. Traub, M. Schwaiger, N. Navab, S. I. Ziegler, A. K. Buck First experience with freehand SPECT for lymphatic mapping in melanoma in upper body Proceedings of Annual Congress of the European Association of of Nuclear Medicine (EANM 2009), Barcelona, Spain, October 2009 (bib)
	T. Wendler, T. Lasser, J. Traub, S. I. Ziegler, N. Navab Freehand SPECT / ultrasound fusion for hybrid image-guided resection Proceedings of Annual Congress of the European Association of of Nuclear Medicine (EANM 2009), Barcelona, Spain, October 2009 (bib)
	T. Lasser, A. Duliu, T. Wendler, S. I. Ziegler, N. Navab Interactive Reconstruction for Freehand SPECT: An Approach to Acquisition Guidance? Proceedings of Annual Congress of the European Association of of Nuclear Medicine (EANM 2009), Barcelona, Spain, October 2009 (bib)
	A. Keil, J. Vogel, G. Lauritsch, N. Navab Dynamic Cone Beam Reconstruction Using a New Level Set Formulation Medical Image Computing and Computer Assisted Intervention (MICCAI), London, UK, September 20-24, 2009. (bib)
	C. Özgür, J. Bieniarz, T. Lasser, S. I. Ziegler, N. Navab, T. Wendler Phenomenological Models for intraoperative Positron Emission Surface Imaging using Handheld Probes Proceedings of World Congress in Medical Physics and Biomedical Engineering (WC 2009), Munich, Germany, September 2009 (bib)
	A. Keil, J. Vogel, G. Lauritsch, N. Navab Dynamic Cone-Beam Reconstruction Using a Variational Level Set Formulation Proc. Int'l Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine (Fully3D), Beijing, P.R. China, September 5-10, 2009. (bib)
	V. Castaneda, S. Atasoy, D. Mateus, N. Navab, A. Meining Reconstructing the Esophagus Surface from Endoscopic Image Sequences 5th Russian-Bavarian Conference on Bio-Medical Engineering, Munich, Germany, July 1-4 2009. (bib)
	A. Ahmadi, T. Klein, N. Navab Advanced Planning and Ultrasound Guidance for Keyhole Neurosurgery in ROBOCAST Russian Bavarian Conference (RBC), Munich, GER, July 2009 (bib)
	A. Ahmadi, T. Klein, N. Navab, R. Roth, R.R. Shamir, L. Joskowicz, E. DeMomi ^?, G. Ferrigno, L. Antiga, R.I. Foroni Advanced Planning and Intra-operative Validation for Robot-Assisted Keyhole Neurosurgery In ROBOCAST International Conference on Advanced Robotics (ICAR), Munich, GER, June 2009 (bib)
	T. Wendler, K. Herrmann, T. Lasser, J. Traub, M. Schwaiger, S. I. Ziegler, N. Navab, A. K. Buck Freehand SPECT: first in-vivo evaluation and comparison to conventional lymphatic mapping Proceedings of Annual Meeting of Society of Nuclear Medicine (SNM 2009), Toronto, Canada, June 2009 (bib)
	A. Karamalis, W. Wein, O. Kutter, N. Navab Fast Hybrid Freehand Ultrasound Volume Reconstruction In Proc. SPIE Medical Imaging, Orlando, Florida, USA, February 2009 (bib)
	M. Blume, A. Keil, N. Navab, M. Rafecas Blind Motion Compensation for Positron-Emission-Tomography SPIE Medical Imaging, Orlando, FL, U.S.A., Feburary 2009 (bib)
	M. Blume, A. Martinez-Möller, A. Keil, N. Navab, M. Rafecas Simultaneous Reconstruction of Image and Motion in Gated Positron-Emission-Tomography Proc. IEEE Nuclear Science Symposium and Medical Imaging Conference, Orlando, FL, U.S.A., October 2009 (bib)
	M. Blume, A. Martinez-Möller, A. Keil, N. Navab, M. Rafecas Joint Reconstruction of Image and Motion in Gated Positron-Emission-Tomography 10th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine, Beijing, China, September 2009 (bib)
	T. Felder, M. Blume, J. Oliver, M. Rafecas ML-EM Implementation on a GPU: Avoiding Simultaneous Read-Modify-Write Processes 10th International Meeting on Fully Three-Dimensional Image Reconstruction in Radiology and Nuclear Medicine, Beijing, China, September 2009 (bib)
2008
	T. Lasser, T. Wendler, J. Traub, S. I. Ziegler, N. Navab Definition of optimal collimator geometries for 3D tomographic thyroid scintigraphy using navigated gamma probes Proceedings of Annual Congress of the European Association of Nuclear Medicine (EANM 2008), Munich, Germany, October 2008 (bib)
	T. Wendler, T. Lasser, A. K. Buck, J. Traub, M. Schwaiger, S. I. Ziegler, N. Navab First case report of 3D tomographic thyroid scintigraphy with tracked gamma probes Proceedings of Annual Congress of the European Association of Nuclear Medicine (EANM 2008), Munich, Germany, October 2008, Eur J Nuc Med Mol Imaging, vol. 35 (Suppl. 2), S129 (bib)
	A. Bigdelou, A. Ladikos, N. Navab Shape from Silhouette in Dynamic Scenes Technical Report at Technical University of Munich (TUM), Munich (DE), August 15, 2008 (bib)
	T. Wendler, A. Hartl, T. Lasser, J. Traub, S. I. Ziegler, N. Navab 3D Intra-operative nuclear imaging for SLNB in neck Proceedings of Annual Meeting of Society of Nuclear Medicine (SNM 2008), New Orleans, USA, June 2008 (bib)
	M. Blume, M. Rafecas, S. I. Ziegler, N. Navab Combined Motion Compensation and Reconstruction for PET Proc. IEEE Nuclear Science Symposium and Medical Imaging Conference, Dresden, Germany, October 2008 (bib)

Working Group

Ahmad Ahmadi

Radin Adi Aizudin Bin Radin Nasirudin

Huseyin Coskun

Danilo Djordjevic

Alexandru O. Duliu

Ralf Gutjahr

Vladimir Haltakov

Peter B Noel

Evin Pınar Ornek^?

Kuangyu Shi

Mira Slavcheva

Christian Unger

Thomas Wendler

		Chair for Computer Aided Medical Procedures & Augmented Reality Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality
THIS WEBPAGE IS DEPRECATED - please visit our new website

THIS WEBPAGE IS DEPRECATED - please visit our new website