Evaluation of gastric antral motility in four dimensions. - Helmar Bergmann; Greg Minear; Andrea Kugi; Georg Stacher (VBC, 1994)

Cocepts and Results in the Development of a Hybrid Tracking System for Computer Aided Surgery. - Wolfgang Birkfellner; Franz Watzinger; Felix Wanschitz; Georg Enislidis; Michael Truppe; Rolf Ewers; Helmar Bergmann (MICCAI, 1998)

Calibration of tracking systems in a surgical environment. - Wolfgang Birkfellner; Franz Watzinger; Felix Wanschitz; Rolf Ewers; Helmar Bergmann (IEEE Trans. Medical Imaging, 1998)

Computer-Aided Implant Dentistry - An Early Report. - Wolfgang Birkfellner; Peter Solar; André Gahleitner; Klaus Huber; Franz Kainberger; Joachim Kettenbach; Peter Homolka; Markus Diemling; Georg Watzek; Helmar Bergmann (MICCAI, 1999)

Development of the Varioscope AR. A see-through HMD for computer-aided surgery. - Wolfgang Birkfellner; Klaus Huber; Franz Watzinger; Franz Figl; Felix Wanschitz; Rudolf Hanel; Dietmar Rafolt; Rolf Ewers; Helmar Bergmann (ISAR, 2000)

The Varioscope AR - A Head-Monted Operating Microscope for Augmented Reality. - Wolfgang Birkfellner; Michael Figl; Klaus Huber; Franz Watzinger; Felix Wanschitz; Rudolf Hanel; Arne Wagner; Dietmar Rafolt; Rolf Ewers; Helmar Bergmann (MICCAI, 2000)

Accuracy of a Navigation System for Computer-Aided Oral Implantology. - Wolfgang Birkfellner; Felix Wanschitz; Franz Watzinger; Klaus Huber; Michael Figl; Christian Schopper; Rudolf Hanel; Franz Kainberger; Joachim Kettenbach; Sanda Patruta; Rolf Ewers; Helmar Bergmann (MICCAI, 2000)

A Modular Software System for Computer Aided Surgery and Its First Application in Oral Implantology. - Wolfgang Birkfellner; Klaus Huber; Alan Larson; Dennis P. Hanson; Markus Diemling; Peter Homolka; Helmar Bergmann (IEEE Trans. Medical Imaging, 2000)

Calibration of a head-mounted operating microscope for augmented reality visualization in CAS. - Wolfgang Birkfellner; Michael Figl; Klaus Huber; Franz Watzinger; Felix Wanschitz; Rudolf Hanel; Johann Hummel; Rolf Ewers; Helmar Bergmann (CARS, 2001)

Fusion of MR and CT scans of the pelvis in cases of malignant bone tumors. - Wolfgang Birkfellner; Eva Schwameis; Friedrich Vorbeck; Rudolf Hanel; Wolfgang Greimel; Johann Hummel; Michael Figl; Franz Kainberger; Herwig Imhof; Rainer Kotz; Helmar Bergmann (CARS, 2001)

Current Status of the Varioscope AR, a Head-Mounted Operating Microscope for Computer-Aided Surgery. - Michael Figl; Wolfgang Birkfellner; Johann Hummel; Rudolf Hanel; Peter Homolka; Franz Watzinger; Felix Wanschitz; Rolf Ewers; Helmar Bergmann (ISAR, 2001)

Calibration of projection parameters in the varioscope AR, a head-mounted display for augmented-reality visualization in image-guided therapy. - Wolfgang Birkfellner; Michael Figl; Klaus Huber; Johann Hummel; Rudolf A. Hanel; Peter Homolka; Franz Watzinger; Felix Wanschitz; Rolf Ewers; Helmar Bergmann (Image-Guided Procedures, 2001)

The Control Unit for a Head Mounted Operating Microscope Used for Augmented Reality Visualization in Computer Aided Sugery. - Michael Figl; Wolfgang Birkfellner; Christopher Ede; Johann Hummel; Rudolf Hanel; Franz Watzinger; Felix Wanschitz; Rolf Ewers; Helmar Bergmann (ISMAR, 2002)

Stereoscopic visualization in the varioscope AR: a see-through head-mounted display for surgical navigation. - Wolfgang Birkfellner; Michael Figl; Christian Matula; Johann Hummel; Rudolf A. Hanel; Herwig Imhof; Felix Wanschitz; Arne Wagner; Franz Watzinger; Helmar Bergmann (Image-Guided Procedures, 2002)

PC-based control unit for a head-mounted operating microscope for augmented-reality visualization in surgical navigation. - Michael Figl; Wolfgang Birkfellner; Franz Watzinger; Felix Wanschitz; Johann Hummel; Rudolf A. Hanel; Rolf Ewers; Helmar Bergmann (Image-Guided Procedures, 2002)

Laboratory assessment of a miniature electromagnetic tracker. - Johann Hummel; Wolfgang Birkfellner; Michael Figl; C. Haider; Rudolf Hanel; Helmar Bergmann (Image-Guided Procedures, 2002)

A Head-Mounted Operating Binocular for Augmented Reality Visualization in Medicine - Design and Initial Evaluation. - Wolfgang Birkfellner; Michael Figl; Klaus Huber; Franz Watzinger; Felix Wanschitz; Johann Hummel; Rudolf Hanel; Wolfgang Greimel; Peter Homolka; Rolf Ewers; Helmar Bergmann (IEEE Trans. Medical Imaging, 2002)

Calibration of an optical see-through head-mounted display with variable zoom and focus for applications in computer-assisted interventions. - Michael Figl; Wolfgang Birkfellner; Johann Hummel; Christopher Ede; Rudolf Hanel; Helmar Bergmann (Image-Guided Procedures, 2003)

Navigation system for flexible endoscopes. - Johann Hummel; Michael Figl; Wolfgang Birkfellner; Michael Häfner; Christian Kollmann; Helmar Bergmann (Image-Guided Procedures, 2003)

Automatic calibration of an optical see-through head-mounted display for augmented reality applications in computer-assisted interventions. - Michael Figl; Christopher Ede; Wolfgang Birkfellner; Johann Hummel; Rudolf Seemann; Helmar Bergmann (Image-Guided Procedures, 2004)

Hybrid tracking system for flexible endoscopes. - Johann Hummel; Michael Figl; Wolfgang Birkfellner; Christopher Ede; Rudolf Seemann; Helmar Bergmann (Image-Guided Procedures, 2004)

Fast DRR Generation for 2D/3D Registration. - Wolfgang Birkfellner; Rudolf Seemann; Michael Figl; Johann Hummel; Christopher Ede; Peter Homolka; Xinhui Yang; Peter Niederer; Helmar Bergmann (MICCAI (2), 2005)

Design and automatic calibration of a head mounted operating binocular for augmented reality applications in computer-aided surgery. - Michael Figl; Christopher Ede; Wolfgang Birkfellner; Johann Hummel; Rudolf Hanel; Helmar Bergmann (Image-Guided Procedures, 2005)

Standardized evaluation method for electromagnetic tracking systems. - Johann Hummel; Calvin R. Maurer Jr.; Michael Figl; Michael R. Bax; Helmar Bergmann; Wolfgang Birkfellner; Ramin Shahidi (Image-Guided Procedures, 2005)

A fully automated calibration method for an optical see-through head-mounted operating microscope with variable zoom and focus. - Michael Figl; Christopher Ede; Johann Hummel; Felix Wanschitz; Rolf Ewers; Helmar Bergmann; Wolfgang Birkfellner (IEEE Trans. Medical Imaging, 2005)

Endoscopic navigation system using 2D/3D registration. - Johann Hummel; Michael Figl; Helmar Bergmann; Wolfgang Birkfellner (Image-Guided Procedures, 2006)

Stochastic rank correlation for slice-to-volume registration of fluoroCT/CT imaging. - Wolfgang Birkfellner; Michael Figl; Helmar Bergmann (Image-Guided Procedures, 2007)

Motion correction for radiation therapy of prostate using B-mode ultrasound. - Johann Hummel; Michael Figl; Jörg Schmidbauer; Martina Tinzl; Helmar Bergmann; Wolfgang Birkfellner (Image-Guided Procedures, 2007)

The Zernike Expansion - An Example of a Merit Function for 2D/3D Registration Based on Orthogonal Functions. - Shuo Dong; Joachim Kettenbach; Isabella Hinterleitner; Helmar Bergmann; Wolfgang Birkfellner (MICCAI (2), 2008)

Evaluation of dynamic electromagnetic tracking deviation. - Johann Hummel; Michael Figl; Michael R. Bax; Ramin Shahidi; Helmar Bergmann; Wolfgang Birkfellner (Image-Guided Procedures, 2009)

Towards real-time 2D/3D registration for organ motion monitoring in image-guided radiation therapy. - Christelle Gendrin; Jakob Spoerk; Christoph Bloch; Supriyanto A. Pawiro; Christoph Weber; Michael Figl; Primoz Markelj; Franjo Pernus; Dietmar Georg; Helmar Bergmann; Wolfgang Birkfellner (Image-Guided Procedures, 2010)

A new gold-standard dataset for 2D/3D image registration evaluation. - Supriyanto A. Pawiro; Primoz Markelj; Christelle Gendrin; Michael Figl; Markus Stock; Christoph Bloch; Christoph Weber; Ewald Unger; Iris Nöbauer; Franz Kainberger; Helga Bergmeister; Dietmar Georg; et al. (Image-Guided Procedures, 2010)

Comparison of two navigation system designs for flexible endoscopes using abdominal 3D ultrasound. - Marcus Kaar; Rainer Hoffmann 001; Helmar Bergmann; Michael Figl; Christoph Bloch; Alfred Kratochwil; Wolfgang Birkfellner; Johann Hummel (Image-Guided Procedures, 2011)

Real-Time Intensity Based 2D/3D Registration for Tumor Motion Tracking During Radiotherapy. - Hugo Furtado; Christelle Gendrin; Christoph Bloch; Jakob Spoerk; Suprianto A. Pawiro; Christoph Weber; Michael Figl; Helmar Bergmann; Markus Stock; Dietmar Georg; Wolfgang Birkfellner (Bildverarbeitung für die Medizin, 2012)

Real-time 2D/3D registration for tumor motion tracking during radiotherapy. - Hugo Furtado; Christelle Gendrin; Christoph Bloch; Jakob Spoerk; Supriyanto A. Pawiro; Christoph Weber; Michael Figl; Markus Stock; Dietmar Georg; Helmar Bergmann; Wolfgang Birkfellner (Image Processing, 2012)