TY - JOUR A1 - Sze, Daniel Y. A1 - Strobel, Norbert A1 - Fahrig, Rebecca A1 - Moore, Teri A1 - Busque, Stephan A1 - Frisoli, Joan K. T1 - Transjugular intrahepatic portosystemic shunt creation in a polycystic liver facilitated by hybrid cross-sectional/angiographic imaging JF - Journal of Vascular and Interventional Radiology (JVIR) N2 - Polycystic liver disease (PCLD) has long been considered to represent a contraindication to transjugular intrahepatic portosystemic shunt (TIPS) creation, primarily because of the risk of hemorrhage. Three-dimensional (3D) navigation within the enlarged and potentially disorienting parenchyma can now be performed during the procedure with the development of C-arm cone-beam computed tomography, which relies on the same equipment already used for angiography. Such a hybrid 3D reconstruction-enabled angiography system was used for safe image guidance of a TIPS procedure in a patient with PCLD. This technology has the potential to expedite any image-guided procedure that requires 3D navigation. Y1 - 2006 U6 - https://doi.org/10.1097/01.rvi.0000208984.17697.58 VL - 17 IS - 4 SP - 711 EP - 715 ER - TY - JOUR A1 - Strobel, Norbert A1 - Spors, Sascha A1 - Rabenstein, Rudolf T1 - Joint audio-video object localization and tracking JF - IEEE Signal Processing Magazine N2 - There has been a tremendous amount of research on object localization either involving microphone arrays or video cameras. Considerable less attention has been paid, however, to object localization and tracking based on joint audio-video processing thus far. This may be related to the lack of suitable algorithms for object localization simultaneously using multimicrophone outputs and color image sequences. In this article, we propose a solution to this problem. Before elaborating on joint audio-video processing, we review some previous work the areas of audio and video object localization. Then a recursive sensor fusion method based on decentralized Kalman filtering is introduced. Unfortunately, the decentralized Kalman filter cannot be directly used for joint audio-video object localization due to specific properties of the audio sensor. By properly adjusting the local audio position estimator, however, we manage to keep the overall architecture. We stress the general methodology. Y1 - 2001 U6 - https://doi.org/10.1109/79.911196 VL - 18 IS - 1 SP - 22 EP - 31 PB - IEEE ER - TY - JOUR A1 - Ramponi, Giovanni A1 - Strobel, Norbert A1 - Mitra, Sanjit K. A1 - Yu, Tian-Hu T1 - Nonlinear unsharp masking methods for image contrast enhancement JF - Journal of Electronic Imaging N2 - In the unsharp masking approach for image enhancement, a fraction of the highpass filtered version of the image is added to the original image to form the enhanced version. The method is simple, but it suffers from two serious drawbacks. First, it enhances the contrast in the darker areas perceptually much more strongly than that in the lighter areas. Second, it enhances the noise and/or digitization effects, particularly in the darker regions, resulting in visually less pleasing enhanced images. In general, noise can be suppressed with lowpass filters, which are associated with the blurring of the edges. On the other hand, contrast can be enhanced with highpass filters, which are associated with noise amplification. A reasonable solution, therefore, is to use suitable nonlinear filters which combine the features of both highpass and lowpass filters. This paper outlines several new methods of unsharp masking based on the use of such nonlinear filters. Computer simulations have verified the superior results obtained using these filters. In addition, a new measure of contrast enhancement is introduced which quantitatively supports the improvement obtained using the proposed methods. Y1 - 1996 U6 - https://doi.org/10.1117/12.242618 VL - 5 IS - 3 SP - 353 EP - 366 ER - TY - CHAP A1 - Bourier, F. A1 - Schneider, H.-J. A1 - Ganslmeier, F. A1 - Heißenhuber, F. A1 - Fischer, R. A1 - Brost, A. A1 - Koch, M. A1 - Strobel, Norbert A1 - Hornegger, J. A1 - Kurzidim, K. T1 - Unterstützung der transseptalen Punktion durch vorherige Überlagerung eines 3D-Volumens von linkem Atrium und Aorta T2 - 77. Jahrestagung Frühjahrestagung der Gesellschaft für Kardiologie Mannheim 27.04. - 30.04.2011 Y1 - 2011 ER - TY - CHAP A1 - Koch, M. A1 - Langenkamp, A. A1 - Kiraly, A. A1 - Brost, A. A1 - Strobel, Norbert A1 - Hornegger, J. T1 - Navigation System with Contact Force Assessment to Guide Pulmonary Vein Isolation Procedures T2 - 23rd Conference of the Society for Medical Innovation and Technology (SMIT) Tel Aviv 01/2011 Y1 - 2011 UR - https://www5.informatik.uni-erlangen.de/Forschung/Publikationen/2011/Koch11-NSW.pdf UR - https://cris.fau.de/publications/113140984/ ER - TY - CHAP A1 - Bourier, F. A1 - Brost, A. A1 - Kleinoeder, A. A1 - Schneider, H.-J. A1 - Heißenhuber, F. A1 - Ganslmeier, P. A1 - Raab, J. A1 - Koch, M. A1 - Hornegger, J. A1 - Strobel, Norbert A1 - Kurzidim, K. T1 - 3D-Visualisation of Cryo-Balloon Ablation Catheters to Evaluate Left Atrial Anatomy for PVI T2 - Venice Arrhythmias 01/2011 Y1 - 2011 UR - https://cris.fau.de/publications/121376684/ ER - TY - CHAP A1 - Bourier, F. A1 - Schneider, H.-J. A1 - Heißenhuber, F. A1 - Ganslmeier, P. A1 - Brost, A. A1 - Koch, M. A1 - Hornegger, J. A1 - Kleinoeder, A. A1 - Kiraly, A. A1 - Barbot, J. A1 - Strobel, Norbert A1 - Kurzidim, K. T1 - Augmented Fluoroscopy to Guide Transseptal Puncture T2 - Venice Arrhythmias 2011 01/2011 Y1 - 2011 ER - TY - CHAP A1 - Bourier, F. A1 - Schneider, H.-J. A1 - Heißenhuber, F. A1 - Ganslmeier, P. A1 - Brost, A. A1 - Koch, M. A1 - Hornegger, J. A1 - Kleinoeder, A. A1 - Kiraly, A. A1 - Barbot, J. A1 - Strobel, Norbert A1 - Kurzidim, K. T1 - Pulmonary Vein Isolation guided by fluoroscopybased 3D-Navigation on a biplane angiography system T2 - Venice Arrhythmias 2011 01/2011 Y1 - 2011 ER - TY - CHAP A1 - Brost, A. A1 - Wimmer, A. A1 - Liao, R. A1 - Hornegger, J. A1 - Strobel, Norbert T1 - Catheter Tracking: Filter-Based vs. Learning-Based T2 - M. Goesele, S. Roth, A. Kuijper, B. Schiele, K. Schindler (eds.) Pattern Recognintion, LNCS, vol. 6376 T2 - Part of the book series: Lecture Notes in Computer Science ((LNIP,volume 6376)) T3 - Lecture Notes in Computer Science - 6376 Y1 - 2010 SN - 978-3-642-15985-5 U6 - https://doi.org/https://doi.org/10.1007/978-3-642-15986-2_30 SP - 293 EP - 302 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Hoffmann, Matthias A1 - Müller, Simone A1 - Kurzidim, Klaus A1 - Strobel, Norbert A1 - Hornegger, Joachim T1 - Robust Identification of Contrasted Frames in Fluoroscopic Images T2 - Bildverarbeitung für die Medizin 2015 N2 - For automatic registration of 3-D models of the left atrium to fluoroscopic images, a reliable classification of images containing contrast agent is necessary. Inspired by previous approaches on contrast agent detection, we propose a learning-based framework which is able to classify contrasted frames more robustly than previous methods, Furthermore, we performed a quantitative evaluation on a clinical data set consisting of 34 angiographies. Our learning-based approach reached a classification rate of 79.5%. The beginning of a contrast injection was detected correctly in 79.4%. Y1 - 2015 SN - 978-3-662-46223-2 SN - 978-3-662-46224-9 U6 - https://doi.org/10.1007/978-3-662-46224-9_6 PB - Springer Vieweg CY - Berlin, Heidelberg ER - TY - CHAP A1 - Hohl, C. A1 - Boese, Jan A1 - Strobel, Norbert A1 - Banckwitz, R. A1 - Lauritsch, G. A1 - Mühlenbruch, G. A1 - Günther, R. W. T1 - Angiographische CT: Messung der Patientendosis T2 - RöFo: Fortschritte auf dem Gebiet Röntgenstrahlen und bildgebenden Verfahren N2 - Ziele: Messung der Organ- und Effektivdosen bei Angiographischen CT-Untersuchungen (ACT) des Kopfs, des Herzens, der Leber sowie der Lendenwirbelsäule (LWS) mit einem anthropomorphen Phantom und Thermolumineszenz Dosimetern (TLD). Methode: ACT erlaubt die Schnittbildgebung von Weichteilstrukturen bei der Verwendung einer C-Bogen Durchleuchtungseinheit mit Flachbilddetektor. Um die sowohl die Organdosen als auch die effektiven Dosen bei ACT-Untersuchungen des Kopfs, des Herzens, der Leber und der LWS zu bestimmen, wurde ein männliches Alderson-Rando-Phantom mit jeweils 129 TLD an 43 Messstellen bestückt. Die Messungen wurden an zwei ACT-Systemen (AXIOM Artis, VB31C, Siemens, Forchheim) mit verschiedenen Detektorgrößen (20×20cm und 30×40cm) durchgeführt. Mit dem 20×20 Detektor wurden der Kopf (70kV, 126 frames, 0,36µGy/frame, 7,9ms/frame), die LWS (90kV, 275 frames, 0,36Gy/frame, 4,9ms/frame) und das Herz (70kV, 126 frames, 0,54µGy/frame, 10,9ms/frame) untersucht. Mit dem 30×40 Detektor wurden der Kopf (84kV, 496 frames, 1,2µGy/frame, 11,6ms/frame) die Leber (90kV, 397 frames, 0,36µGy/frame, 4,9ms/frame) und das Herz (70kV, 248 frames, 0,54µGy/frame, 4,9ms/frame) untersucht. Zusätzlich wurde mit dem 30×40 Detektor noch eine EKG-getriggerte Herz-Untersuchung durchgeführt (992 frames, Phasen-Zentrum 75%, Phasen-Länge 50%, 50% mAs-Modulation). Nach jeder Messung wurden die TLD gewechselt und ausgewertet. Gemäß den ICRP-Empfehlungen sind Organ- und Effektivdosen berechnet worden, die dann mit bekannten Dosiswerten vergleichbarer MSCT-Untersuchungen korreliert wurden. Ergebnis: Die Messungen der effektiven Dosis für den 20×20 Detektor ergaben Werte von 0,2mSv (Kopf), 2,76mSv (LWS) und 1,25mSv (Herz). Mit dem 30×40 Detektor ergaben sich Werte von 2,95mSv (Kopf), 6,71mSv (Leber) und 3,31mSv (Herz, 248 frames). Für die EKG-getriggerte Untersuchung des Herzens ergab sich eine effektive Dosis von 10,88 mSv bei 4 Umläufen (992 frames). Vergleichbare MSCT-Untersuchung belaufen sich auf 2,9mSv (Kopf), 4,8mSv (LWS), 4,3mSv (Leber) und 8,3mSv (Herz). Schlussfolgerung: Da ACT-Systeme mit einer Belichtungsautomatik ausgestattet sind, hängt die effektive Dosis stark vom Patientendurchmesser ab. Bei Messungen mit dem anthropomorphen Phantom konnte gezeigt werden, dass die effektiven Dosen von ACT-Untersuchungen sogar noch unterhalb von vergleichbaren MSCT-Untersuchungen liegen können. Allerdings muss dabei berücksichtigt werden, dass die Bildqualität und insbesondere der Weichteilkontrast nicht vergleichbar sind. Y1 - 2008 U6 - https://doi.org/10.1055/s-2008-1073628 VL - 180 IS - S 1 ER - TY - JOUR A1 - Bourier, Felix A1 - Fahrig, Rebecca A1 - Wang, Paul A1 - Santangeli, Pasquale A1 - Kurzidim, Klaus A1 - Strobel, Norbert A1 - Moore, Teri A1 - Hinkel, Cameron A1 - Al-Ahmad, Amin T1 - Accuracy assessment of catheter guidance technology in electrophysiology procedures: a comparison of a new 3D-based fluoroscopy navigation system to current electroanatomic mapping system JF - Journal of Cardiovascular Electrophysiology N2 - Background: With increasing complexity in electrophysiology (EP) procedures, the use of electroanatomic mapping systems (EAMS) as a supplement to fluoroscopy has become common practice. This is the first study that evaluates spatial and point localization accuracy for 2 current EAMS, CARTO3(®) (Biosense Webster, Diamond Bar, CA, USA) and EnSite Velocity(®) (St. Jude Medical Inc., St. Paul, MN, USA), and for a novel overlay guidance (OG) software (Siemens AG, Forchheim, Germany) in a phantom experiment. Methods and results: A C-arm CT scan was performed on an acrylic phantom containing holes and location markers. Spatial accuracy was assessed for each system using distance measurements involving known markers inside the phantom and properly placed catheters. Anatomical maps of the phantom were acquired by each EAMS, whereas the 3D-based OG software superimposed an overlay image of the phantom, segmented from the C-arm CT data set, onto biplane fluoroscopy. Registration processes and landmark measurements quantitatively assessed the spatial accuracy of each technology with respect to the ground truth phantom. Point localization performance was 0.49 ± 0.25 mm in OG, 0.46 ± 0.17 mm in CARTO3(®) and 0.79 ± 0.83 mm in EnSite(®) . The registration offset between virtual visualization and reality was 1.10 ± 0.52 mm in OG, 1.62 ± 0.77 mm in CARTO3(®) and 2.02 ± 1.21 mm in EnSite(®) . The offset to phantom C-arm CT landmark measurements was 0.30 ± 0.26 mm in OG, 0.24 ± 0.21 mm in CARTO3(®) and 1.32 ± 0.98 mm in EnSite(®) . Conclusions: Each of the evaluated EP guidance systems showed a high level of accuracy; the observed offsets between the virtual 3D visualization and the real phantom were below a clinically relevant threshold of 3 mm. Y1 - 2013 U6 - https://doi.org/10.1111/jce.12264 VL - 25 IS - 1 SP - 74 EP - 83 ER - TY - JOUR A1 - Meyer, Bernhard Christian A1 - Brost, Alexander A1 - Kraitchman, Dara L A1 - Gilson, Wesley D A1 - Strobel, Norbert A1 - Hornegger, Joachim A1 - Lewin, Jonathan S A1 - Wacker, Frank K T1 - Percutaneous punctures with MR imaging guidance: comparison between MR imaging-enhanced fluoroscopic guidance and real-time MR Imaging guidance JF - Radiology N2 - Purpose: To evaluate and compare the technical accuracy and feasibility of magnetic resonance (MR) imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance for percutaneous puncture procedures in phantoms and animals. Materials and methods: The experimental protocol was approved by the institutional animal care and use committee. Punctures were performed in phantoms, aiming for markers (20 each for MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance), and pigs, aiming for anatomic landmarks (10 for MR imaging-enhanced fluoroscopic guidance and five for MR imaging guidance). To guide the punctures, T1-weighted three-dimensional (3D) MR images of the phantom or pig were acquired. Additional axial and coronal T2-weighted images were used to visualize the anatomy in the animals. For MR imaging-enhanced fluoroscopic guidance, phantoms and pigs were transferred to the fluoroscopic system after initial MR imaging and C-arm computed tomography (CT) was performed. C-arm CT and MR imaging data sets were coregistered. Prototype navigation software was used to plan a puncture path with use of MR images and to superimpose it on fluoroscopic images. For real-time MR imaging, an interventional MR imaging prototype for interactive real-time section position navigation was used. Punctures were performed within the magnet bore. After completion, 3D MR imaging was performed to evaluate the accuracy of insertions. Puncture durations were compared by using the log-rank test. The Mann-Whitney U test was applied to compare the spatial errors. Results: In phantoms, the mean total error was 8.6 mm ± 2.8 with MR imaging-enhanced fluoroscopic guidance and 4.0 mm ± 1.2 with real-time MR imaging guidance (P < .001). The mean puncture time was 2 minutes 10 seconds ± 44 seconds with MR imaging-enhanced fluoroscopic guidance and 37 seconds ± 14 with real-time MR imaging guidance (P < .001). In the animal study, a tolerable distance (<1 cm) between target and needle tip was observed for both MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance. The mean total error was 7.7 mm ± 2.4 with MR imaging-enhanced fluoroscopic guidance and 7.9 mm ± 4.9 with real-time MR imaging guidance (P = .77). The mean puncture time was 5 minutes 43 seconds ± 2 minutes 7 seconds with MR imaging-enhanced fluoroscopic guidance and 5 minutes 14 seconds ± 2 minutes 25 seconds with real-time MR imaging guidance (P = .68). Conclusion: Both MR imaging-enhanced fluoroscopic guidance and real-time MR imaging guidance demonstrated reasonable and similar accuracy in guiding needle placement to selected targets in phantoms and animals. Y1 - 2013 U6 - https://doi.org/10.1148/radiol.12120117 VL - 266 IS - 3 SP - 912 EP - 919 ER - TY - JOUR A1 - Brost, Alexander A1 - Raab, Jens A1 - Kleinoeder, Andreas A1 - Kurzendorfer, Tanja A1 - Bourier, Felix A1 - Koch, Martin A1 - Hoffmann, Matthias A1 - Strobel, Norbert A1 - Kurzidim, Klaus A1 - Hornegger, Joachim T1 - Medizinische Bildverarbeitung für die minimal-invasive Behandlung von Vorhofflimmern JF - Deutsche Zeitschrift für klinische Forschung, Innovation und Praxis (DZKF) Y1 - 2013 UR - https://cris.fau.de/publications/113146704/ VL - 17 IS - 6 SP - 36 EP - 41 PB - Mediengruppe Oberfranken Fachverlage GmbH & Co. KG ER - TY - JOUR A1 - Bourier, Felix A1 - Vukajlovic, Dejan A1 - Brost, Alexander A1 - Hornegger, Joachim A1 - Strobel, Norbert A1 - Kurzidim, Klaus T1 - Pulmonary vein isolation supported by MRI-derived 3D-augmented biplane fluoroscopy: a feasibility study and a quantitative analysis of the accuracy of the technique JF - Journal of Cardiovascular Electrophysiology N2 - Background: Despite the advancement of technology in electroanatomic mapping systems (EAMS), fluoroscopy remains a necessary, basic imaging modality for electrophysiology procedures. We present a feasibility study of new software that enables 3D-augmented fluoroscopy in biplane catheterization laboratories for planning and guidance of pulmonary vein isolation (PVI). The computer-assisted overlay registration accuracy was assessed in a clinical setting using an automatic calculation of overlay projection geometry that was derived from hardware sensors in C-arms, detectors, and patient table. Methods: Consecutive patients (n = 89) underwent left atrium (LA) magnetic resonance imaging MRI scan prior to PVI. Ideal ablation lines encircling the ipsilateral pulmonary veins (PVs) at antral level were drawn onto the segmented LA surface. The 3D-model was superimposed onto biplane fluoroscopy and matched with angiographies of LA and PVs. Three-dimensional-overlay projection geometry was automatically calculated from C-arm, detectors, and table sensors. Accuracy of technique was assessed as alignment of MRI-derived 3D overlay and angiographic LA/PV anatomy. Integrity of registered overlay was quantified using landmark measurements. Results: Alignment offsets were 1.3 ± 1.5 mm in left PV, 1.2 ± 1.5 mm in right PV, and 1.1 ± 1.4 mm in LA roof region. Bravais-Pearson correlation of the landmark measurements was r = 0.978 (s < 0.01), mean offset between landmark distance measurements was 1.4 ± 0.78 mm. Average time needed for overlay registration was 9.5 ± 3.5 seconds. Conclusions: MRI-derived 3D-augmented fluoroscopy demonstrated a high level of accuracy when compared with LA/PV angiography. The new system could be especially useful to guide procedures not supported by EAMS, such as cryotechnique PVI. Y1 - 2012 U6 - https://doi.org/10.1111/jce.12009 VL - 24 IS - 2 SP - 113 EP - 120 ER - TY - JOUR A1 - Brost, Joachim A1 - Wimmer, Andreas A1 - Liao, Rui A1 - Bourier, Felix A1 - Koch, Martin A1 - Strobel, Norbert A1 - Kurzidim, Klaus A1 - Hornegger, Joachim T1 - Constrained registration for motion compensation in atrial fibrillation ablation procedures JF - IEEE Trans Med Imaging N2 - Fluoroscopic overlay images rendered from preoperative volumetric data can provide additional anatomical details to guide physicians during catheter ablation procedures for treatment of atrial fibrillation (AFib). As these overlay images are often compromised by cardiac and respiratory motion, motion compensation methods are needed to keep the overlay images in sync with the fluoroscopic images. So far, these approaches have either required simultaneous biplane imaging for 3-D motion compensation, or in case of monoplane X-ray imaging, provided only a limited 2-D functionality. To overcome the downsides of the previously suggested methods, we propose an approach that facilitates a full 3-D motion compensation even if only monoplane X-ray images are available. To this end, we use a training phase that employs a biplane sequence to establish a patient specific motion model. Afterwards, a constrained model-based 2-D/3-D registration method is used to track a circumferential mapping catheter. This device is commonly used for AFib catheter ablation procedures. Based on the experiments on real patient data, we found that our constrained monoplane 2-D/3-D registration outperformed the unconstrained counterpart and yielded an average 2-D tracking error of 0.6 mm and an average 3-D tracking error of 1.6 mm. The unconstrained 2-D/3-D registration technique yielded a similar 2-D performance, but the 3-D tracking error increased to 3.2 mm mostly due to wrongly estimated 3-D motion components in X-ray view direction. Compared to the conventional 2-D monoplane method, the proposed method provides a more seamless workflow by removing the need for catheter model re-initialization otherwise required when the C-arm view orientation changes. In addition, the proposed method can be straightforwardly combined with the previously introduced biplane motion compensation technique to obtain a good trade-off between accuracy and radiation dose reduction. Y1 - 2012 U6 - https://doi.org/10.1109/tmi.2011.2181184 VL - 31 IS - 4 SP - 870 EP - 881 ER - TY - JOUR A1 - Maier, Andreas A1 - Wigstrom, Lars A1 - Hofmann, Hannes G A1 - Hornegger, Joachim A1 - Zhu, Lei A1 - Strobel, Norbert A1 - Fahrig, Rebecca T1 - Three-dimensional anisotropic adaptive filtering of projection data for noise reduction in cone beam CT JF - Medical Physic N2 - Purpose: The combination of quickly rotating C-arm gantry with digital flat panel has enabled the acquisition of three-dimensional data (3D) in the interventional suite. However, image quality is still somewhat limited since the hardware has not been optimized for CT imaging. Adaptive anisotropic filtering has the ability to improve image quality by reducing the noise level and therewith the radiation dose without introducing noticeable blurring. By applying the filtering prior to 3D reconstruction, noise-induced streak artifacts are reduced as compared to processing in the image domain. Methods: 3D anisotropic adaptive filtering was used to process an ensemble of 2D x-ray views acquired along a circular trajectory around an object. After arranging the input data into a 3D space (2D projections + angle), the orientation of structures was estimated using a set of differently oriented filters. The resulting tensor representation of local orientation was utilized to control the anisotropic filtering. Low-pass filtering is applied only along structures to maintain high spatial frequency components perpendicular to these. The evaluation of the proposed algorithm includes numerical simulations, phantom experiments, and in-vivo data which were acquired using an AXIOM Artis dTA C-arm system (Siemens AG, Healthcare Sector, Forchheim, Germany). Spatial resolution and noise levels were compared with and without adaptive filtering. A human observer study was carried out to evaluate low-contrast detectability. Results: The adaptive anisotropic filtering algorithm was found to significantly improve low-contrast detectability by reducing the noise level by half (reduction of the standard deviation in certain areas from 74 to 30 HU). Virtually no degradation of high contrast spatial resolution was observed in the modulation transfer function (MTF) analysis. Although the algorithm is computationally intensive, hardware acceleration using Nvidia's CUDA Interface provided an 8.9-fold speed-up of the processing (from 1336 to 150 s). Conclusions: Adaptive anisotropic filtering has the potential to substantially improve image quality and/or reduce the radiation dose required for obtaining 3D image data using cone beam CT. Y1 - 2011 U6 - https://doi.org/10.1118/1.3633901 VL - 38 IS - 11 SP - 5896 EP - 5909 ER - TY - JOUR A1 - Yatziv, Liron A1 - Ibarz, Julian A1 - Strobel, Norbert A1 - Datta, Saurabh A1 - Sapiro, Guillermo T1 - Esophagus Silhouette Extraction and Reconstruction From Fluoroscopic Views for Cardiac Ablation Procedure Guidance JF - IEEE Transactions on Information Technology in Biomedicine N2 - Cardiac ablation involves the risk of serious complications when thermal injury to the esophagus occurs. This paper proposes to reduce the risk of such injuries by a proactive visualization technique, improving physician awareness of the esophagus location in the absence of or in addition to a reactive monitoring device such as a thermal probe. This is achieved by combining a graphical representation of the esophagus with live fluoroscopy. Toward this goal, we present an automated method to reconstruct and visualize a 3-D esophagus model from fluoroscopy image sequences acquired using different C-arm viewing directions. In order to visualize the esophagus under fluoroscopy, it is first biomarked by swallowing a contrast agent such as barium. Images obtained in this procedure are then used to automatically extract the 2-D esophagus silhouette and reconstruct a 3-D surface of the esophagus internal wall. Once the 3-D representation has been computed, it can be visualized using fluoroscopy overlay techniques. Compared to 3-D esophagus imaging using CT or C-arm CT, our proposed fluoroscopy method requires low radiation dose and enables a simpler workflow on geometry-calibrated standard C-arm systems. Y1 - 2011 U6 - https://doi.org/10.1109/TITB.2011.2162247 VL - 15 IS - 5 SP - 703 EP - 708 PB - IEEE ER - TY - CHAP A1 - Brost, Alexander A1 - Wu, Wen A1 - Koch, Martin A1 - Wimmer, Martin A1 - Chen, Terrence A1 - Liao, Rui A1 - Hornegger, Joachim A1 - Strobel, Norbert T1 - Combined Cardiac and Respiratory Motion Compensation for Atrial Fibrillation Ablation Procedures T2 - Medical Image Computing and Computer-Assisted Intervention N2 - Catheter ablation of atrial fibrillation has become an accepted treatment option if a patient no longer responds to or tolerates drug therapy. A main goal is the electrical isolation of the pulmonary veins attached to the left atrium. Catheter ablation may be performed under fluoroscopic image guidance. Due to the rather low soft-tissue contrast of X-ray imaging, the heart is not visible in these images. To overcome this problem, overlay images from pre-operative 3-D volumetric data can be used to add anatomical detail. Unfortunately, this overlay is compromised by respiratory and cardiac motion. In the past, two methods have been proposed to perform motion compensation. The first approach involves tracking of a circumferential mapping catheter placed at an ostium of a pulmonary vein. The second method relies on a motion estimate obtained by localizing an electrode of the coronary sinus (CS) catheter. We propose a new motion compensation scheme which combines these two methods. The effectiveness of the proposed method is verified using 19 real clinical data sets. The motion in the fluoroscopic images was estimated with an overall average error of 0.55 mm by tracking the circumferential mapping catheter. By applying an algorithm involving both the CS catheter and the circumferential mapping catheter, we were able to detect motion of the mapping catheter from one pulmonary vein to another with a false positive rate of 5.8 %. T3 - Lecture Notes in Computer Science - 6891 Y1 - 2011 SN - 978-3-642-23622-8 SN - 978-3-642-23623-5 U6 - https://doi.org/10.1007/978-3-642-23623-5_68 VL - 14 SP - 540 EP - 547 PB - Springer CY - Berlin, Heidelberg ER - TY - JOUR A1 - Brost, Alexander A1 - Liao, Rui A1 - Strobel, Norbert A1 - Hornegger, Joachim T1 - Respiratory motion compensation by model-based catheter tracking during EP procedures JF - Medical Image Analysis N2 - In many cases, radio-frequency catheter ablation of the pulmonary veins attached to the left atrium still involves fluoroscopic image guidance. Two-dimensional X-ray navigation may also take advantage of overlay images derived from static pre-operative 3D volumetric data to add anatomical details otherwise not visible under X-ray. Unfortunately, respiratory motion may impair the utility of static overlay images for catheter navigation. We developed a novel approach for image-based 3D motion estimation and compensation as a solution to this problem. It is based on 3D catheter tracking which, in turn, relies on 2D/3D registration. To this end, a bi-plane C-arm system is used to take X-ray images of a special circumferential mapping catheter from two directions. In the first step of the method, a 3D model of the device is reconstructed. Three-dimensional respiratory motion at the site of ablation is then estimated by tracking the reconstructed catheter model in 3D based on bi-plane fluoroscopy. Phantom data and clinical data were used to assess model-based catheter tracking. Our phantom experiments yielded an average 2D tracking error of 1.4 mm and an average 3D tracking error of 1.1 mm. Our evaluation of clinical data sets comprised 469 bi-plane fluoroscopy frames (938 monoplane fluoroscopy frames). We observed an average 2D tracking error of 1.0 ± 0.4 mm and an average 3D tracking error of 0.8 ± 0.5 mm. These results demonstrate that model-based motion-compensation based on 2D/3D registration is both feasible and accurate. Y1 - 2010 U6 - https://doi.org/10.1016/j.media.2010.05.006 VL - 14 IS - 5 SP - 695 EP - 706 ER - TY - CHAP A1 - Hohl, C. A1 - Boese, Jan A1 - Strobel, Norbert A1 - Banckwitz, R. A1 - Mühlenbruch, G. A1 - Günther, R. W. A1 - Honnef, D. T1 - Angiographische CT: Messung der Strahlenexposition bei Kindern T2 - RöFo: Fortschritte auf dem Gebiet Röntgenstrahlen und bildgebenden Verfahren N2 - Ziele: Messung der Organ- und Effektivdosen bei Angiographischen CT-Untersuchungen (ACT) des Kopfs und des Herzens mit einem pädiatrischen anthropomorphen Phantom und Thermolumineszenz Dosimetern (TLD). Methode: ACT erlaubt die Schnittbildgebung von Weichteilstrukturen bei der Verwendung einer C-Bogen Durchleuchtungseinheit mit Flachbilddetektor. Bei Kindern wird die ACT für interventionelle Eingriffe bei angeborenen Herzfehlern oder bei Behandlung cerebro-vaskulärer Malformationen genutzt. Um die sowohl die Organdosen als auch die effektiven Dosen bei ACT-gestützten Interventionen im Bereich des Kopfs und des Herzens zu bestimmen, wurde ein anthropomorphes Phantom eines 5-jährigen Jungen (Braden ATOM, CIRS, Norfolk, VA, USA) mit jeweils 132 TLD an 44 Messstellen bestückt. Die Messungen wurden an einem ACT-Systemen (AXIOM Artis dFC, VB31C, Siemens, Forchheim) mit einer Detektorgrößen von 20×20cm durchgeführt. Die Messungen wurden mit vom Hersteller empfohlenen Standard Hoch-Kontrast-Protokollen für cranielle (70kV, 0.36µGy/frame, 126 frames) und cardiale (70kV, 0.54µGy/frame Detektor-Eingangsdosis, 126 frames) Untersuchungen durchgeführt. Nach jeder Messung wurden die TLD entnommen und ausgewertet. Gemäß den ICRP-Empfehlungen sind Organ- und Effektivdosen berechnet worden, die dann mit bekannten Dosiswerten vergleichbarer MSCT-Untersuchungen korreliert wurden. Ergebnis: Die gemessenen effektive Dosiswerte betrugen 0,11 mSv für die cranielle und 0,46 mSv für die cardiale ACT-Untersuchung. Diese Werte waren deutlich niedriger als vergleichbare Literaturwerte für MSCT-Untersuchungen (1,8 mSv craniell und 9 mSv cardial). Schlussfolgerung: Abhängig von der klinischen Anwendung können ACT-Untersuchungen bei Kindern sogar mit einer geringeren Strahlenexposition verbunden sein als vergleichbare MSCT-Untersuchungen. Bei dem Vergleich von Dosiswerten von ACT und MSCT muss jedoch die unterschiedliche Bildqualität und insbesondere der geringere Weichteilkontrast berücksichtigt werden. Y1 - 2008 U6 - https://doi.org/10.1055/s-2008-1073550 VL - 180 IS - S 1 ER - TY - CHAP A1 - Strobel, Norbert A1 - Meissner, Oliver A1 - Boese, Jan A1 - Brunner, Thomas A1 - Heigl, Benno A1 - Hoheisel, Martin A1 - Lauritsch, Günter A1 - Nagel, Markus A1 - Pfister, Marcus A1 - Rührnschopf, Ernst-Peter A1 - Scholz, Bernhard A1 - Schreiber, Bernd A1 - Spahn, Martin A1 - Zellerhoff, Michael A1 - Klingenbeck-Regn, Klaus T1 - 3D Imaging with Flat-Detector C-Arm Systems T2 - Multislice CT - Medical Radiology N2 - Three-dimensional (3D) C-arm computed tomography is a new and innovative imaging technique. It uses two-dimensional (2D) X-ray projections acquired with a flat-panel detector C-arm angiography system to generate CT-like images. To this end, the C-arm system performs a sweep around the patient, acquiring up to several hundred 2D views. They serve as input for 3D cone-beam reconstruction. Resulting voxel data sets can be visualized either as cross-sectional images or as 3D data sets using different volume rendering techniques. Initially targeted at 3D high-contrast neurovascular applications, 3D C-arm imaging has been continuously improved over the years and is now capable of providing CT-like soft-tissue image quality. In combination with 2D fluoroscopic or radiographic imaging, information provided by 3D C-arm imaging can be valuable for therapy planning, guidance, and outcome assessment all in the interventional suite. Y1 - 2009 SN - 978-3-540-33125-4 SN - 978-3-540-33124-7 U6 - https://doi.org/10.1007/978-3-540-33125-4_3 SP - 33 EP - 51 PB - Springer CY - Berlin, Heidelberg ET - 3. ER - TY - CHAP A1 - Strobel, Norbert A1 - Spors, Sascha A1 - Rabenstein, Rudolf ED - Brandstein, Michael ED - Ward, Darren T1 - Joint Audio-Video Signal Processing for Object Localization and Tracking T2 - Microphone Arrays N2 - Applications such as videoconferencing, automatic scene analysis, or security surveillance involving acoustic sources can benefit from object localization within a complex scene. Many single-sensor techniques already exist for this purpose. They are, e.g., based on microphone arrays, video cameras, or range sensors. Since all of these sensors have their specific strengths and weaknesses, it is often advantageous to combine information from various sensor modalities to arrive at more robust position estimates. This chapter presents a joint audio-video signal processing methodology for object localizing and tracking. The approach is based on a decentralized Kalman filter structure modified such that different sensor measurement models can be incorporated. Such a situation is typical for combined audio-video sensing, since different coordinate systems are usually used for the camera system and the microphone array. At first, the decentralized estimation algorithm is presented. Then a speaker localization example is discussed. Finally, some estimation results are shown. T3 - Digital Signal Processing - 4 Y1 - 2001 SN - 978-3-662-04619-7 SN - 978-3-642-07547-6 U6 - https://doi.org/10.1007/978-3-662-04619-7_10 SP - 203 EP - 225 PB - Springer CY - Berlin, Heidelberg ER - TY - CHAP A1 - Strobel, Norbert ED - Girod, B. ED - Greiner, G. ED - Niemann, H. T1 - Fusion of Multisensor Data T2 - Principles of 3D Image Analysis and Synthesis Y1 - 2000 SP - 309 EP - 322 PB - Kluwer Academic Publishers CY - Boston, USA ER - TY - CHAP A1 - Strobel, Norbert A1 - Rabenstein, Rudolf ED - Girod, G. ED - Greiner, G. ED - Niemann, H. T1 - Object Localization using Audio and Video Signals T2 - Principles of 3D Image Analysis and Synthesis Y1 - 2000 SP - 322 EP - 334 PB - Kluwer Academic Publishers CY - Boston, USA ER - TY - THES A1 - Strobel, Norbert A1 - Mitra, Sanjit K. T1 - Multiresolution-based storage, browsing and retrieval for digital image libraries N2 - In this dissertation, the focus is on algorithms for progressive-resolution image transmission, storage and retrieval. The resulting methods are designed to support a fast system response, to provide an intuitive image representation, and to achieve lossless image compression at competitive bit rates. Average interpolation subdivision (AIS) is introduced. It offers a sound mathematical framework for the derivation of algorithms providing the functionality required. To proceed from AIS to image compression, a multiresolution analysis is added. It allows the construction of wavelet transforms and leads to AIS filter banks. For lossless image compression, reversible wavelet transforms (RWTs) are constructed. To that end, an interband prediction structure for AIS filter banks is first derived. Afterwards rounding operations are introduced, and RWTs are assembled. Reversible AIS filter banks deliver acceptable bit rates when applied to the lossless compression of monochrome images. A time-domain filter analysis confirms that AIS filters are nearly optimal given their structural constraints. Better results are still obtainable. They, however, require an enhanced interband prediction framework. If images of arbitrary size are to be ingested into a database, an efficient method is needed to process signal boundaries. It is demonstrated that interband-prediction offers an elegant and practical solution for this task. The reversible AIS filter banks are finally applied to the lossless compression of color images. Color images offer an excellent opportunity for the design of algorithms which are applicable to a much wider range of multispectral imagery. A new lossless compression method is proposed. It executes a reversible wavelet transform first and then applies adaptive spectral transforms to associated color subbands. Very good results have been obtained. Yet, little computational complexity has been added. Simulation results are included. They verify the rationale of this approach. Y1 - 1998 UR - https://api.semanticscholar.org/CorpusID:60343753 PB - Department of Electrical and Computer Engineering, Signal and Image Processing Laboratory CY - Santa Barbara, USA ER - TY - JOUR A1 - Koch, Martin A1 - Hoffmann, Matthias A1 - Pfister, Marcus A1 - Hornegger, Joachim A1 - Strobel, Norbert T1 - Optimized viewing angles for cardiac electrophysiology ablation procedures JF - International Journal of Computer Assisted Radiology and Surgery N2 - Purpose: Catheter ablation is a common treatment option for atrial fibrillation (AF). Interventional C-arm X-ray systems are used for guiding AF procedures, employing standard view positions. Since the projection angles are not adapted to the individual patient anatomy, standard projections do not necessarily offer the best views of important anatomical structures. Using a pre-procedural 3D data set acquired with MRI or CT, suitable ablation sites (lines) can be identified in advance so an ablation plan can be superimposed on fluoroscopic images to guide the procedure. Methods: A method was developed to estimate optimized projection views for biplane X-ray C-arm systems based on planning data for AF ablation procedures. The estimated viewing angles were compared to standard angulations using an objective quality metric, the length of the planned ablation line as seen under X-ray. This method was tested using 35 clinical datasets annotated with planned ablation lines for ipsilateral pulmonary vein isolation. Results: The optimized views computed using the new method yielded 28 % less foreshortening of pre-planned ablation lines on average. In one case, anatomy-based view calculation lead to a 69 % reduction in foreshortening. Conclusion: The commonly used standard views provide reasonable a priori choices, and some improvement is possible by switching among common angulations depending on the treatment region. Further gains are possible by using anatomy-optimized biplane C-arm angulations. Y1 - 2014 U6 - https://doi.org/10.1007/s11548-014-1103-z VL - 10 SP - 651 EP - 664 PB - Springer ER - TY - JOUR A1 - Kurzendorfer, Tanja A1 - Girard, Erin A1 - Gralewski, Kevin A1 - Kleinoeder, Andreas A1 - Kiraly, Atilla P A1 - Strobel, Norbert A1 - Dori, Yoav T1 - New biplane x-ray magnetic resonance image fusion prototype for 3D enhanced cardiac catheterization in congenital heart diseases JF - Journal of Cardiovascular Magnetic Resonance N2 - Background X-ray magnetic resonance fusion (XMRF) is used to enhance fluoroscopically guided catheterization procedures. We present a new method for biplane XMRF involving an augmented fluoroscopy prototype (Siemens, Forchheim, Germany). With this software it is possible to register 3D MRI data to biplane X-ray projections based on internal markers, without the need for a C-arm CT to perform 3D/3D registration. The software supports overlaying volume rendered data as well as multiple surface models. Visualization techniques, such as contour or solid rendering and surface carving are supported to allow for clear presentation of complex 3D structures. Methods We reviewed data obtained with different visualization methods on 20 patients that underwent clinical XMRF procedures. Surface models were generated by threshold based segmentation from high resolution MRA (syngo Twist or Navigator gated 3D flash IR sequence) of structures of interest using Mimics (Leuven, Belgium). Initial registration was achieved through planar alignment of the volume in anterior-posterior (AP) and lateral projections matching anatomical landmarks, such as the heart and vessel borders. In addition, the registration accuracy of the prototype was assessed using a phantom by measuring the maximum distance between a single point and the 3D model boundaries in comparison to the boundaries seen on fluoroscopy. Results The maximum segmentation time was 10 min and the initial registration required less than 30 sec. Registration was performed without the need for contrast injection or additional radiation exposure. The registration error based on phantom measurements was 2.2 ± 1.1 mm in the AP projection and 1.36 ± 0.7 mm in the lateral projection. For surface rendered data, solid rendering with carving provided the optimal display of complex 3D data. In contrast to volume rendering, solid surface rendering provides delineation of the 3D relation between objects and clear visualization of internal structures such as ostia of the vessels and muscle bundles using the carving feature, see Figure 1. Contour rendering offered reasonable visualization for smooth, uncomplicated structures like the atria, but it was not ideal for complex overlapping structures due to missing 3D depth information. When multiple surfaces are loaded, contour rendering was, however, found to be useful in combination with solid rendered structures to provide a see-through 3D relation between multiple structures Conclusions The prototype demonstrated a high level of accuracy for fluoroscopic overlays. Biplane internal marker based registration can be performed quickly, without the need for additional radiation or contrast. We found solid rendering of surface models in combination with carving techniques to be most useful for visualization. This new biplane XMRF technique has the potential to provide enhanced guidance under fluoroscopy by integrating 3D information and to reduce radiation during complicated catheterization procedures. Funding This project is funded by a research grant from Siemens, AG, Healthcare, Forchheim, Germany. The concepts and information presented in this paper are based on research and are not commercially available. Y1 - 2014 U6 - https://doi.org/10.1186/1532-429X-16-S1-O103 VL - 16 IS - Supplement 1 ER - TY - JOUR A1 - Koch, Martin W. A1 - Brost, Alexander A1 - Bourier, Felix A1 - Hornegger, Joachim A1 - Strobel, Norbert T1 - Automatic planning of atrial fibrillation ablation lines using landmark-constrained nonrigid registration JF - Journal of Medical Imaging N2 - Catheter ablation is a common treatment option for drug-refractory atrial fibrillation. In many cases, pulmonary vein isolation is the treatment of choice. With current fluoro overlay methods or electroanatomic mapping systems, it is possible to visualize three-dimensional (3-D) anatomy as well as target ablation lines to provide additional context information. Today, however, these lines need to be set manually before the procedure by the physician, which may interrupt the clinical workflow. As a solution, we present an automatic approach for the planning of ablation target lines. Our method works on surface models extracted from 3-D images. To propose suitable ablation lines, a reference model annotated with reference ablation lines is nonrigidly registered to the model segmented from a new patient’s 3-D data. After registration, the reference plan is transferred from the reference anatomy to the individual patient anatomy. Due to the high anatomical variations observed in clinical practice, additional landmark constraints are employed in the registration process to increase the robustness of our approach. We evaluated our method on 43 clinical datasets by benchmarking it against professionally planned ablation lines and achieved an average error over all datasets of 2.7±2.0  mm . A qualitative evaluation of the ablation planning lines matched clinical expectations. Y1 - 2014 U6 - https://doi.org/10.1117/1.JMI.1.1.015002 VL - 1 IS - 1 ER - TY - GEN A1 - Wu, W. A1 - Chen, T. A1 - Strobel, Norbert A1 - Comaniciu, D. T1 - Method and system for ablation catheter and circumferential mapping catheter tracking in fluoroscopic images (Patent, US 9,002,436) Y1 - 2015 ER - TY - GEN A1 - Barbot, Julien Christian A1 - Kiraly, Atilla Peter A1 - Strobel, Norbert T1 - Localization and tracking of cryo-balloon during interventional fluoroscopy imaging (Patent, US 8989463B2) N2 - A method for the detection of a balloon catheter within a fluoroscopic image, including: removing noise from a fluoroscopic image; detecting edges of a balloon catheter in the fluoroscopic image, wherein the detected edges include subsets of connected edges; extracting an edge subset from the subsets of connected edges; fitting a model to the extracted edge subset; removing outliers of the extracted edge subset based on the fitting of the model; adding the extracted edge subset without the outlier to a data set; repeating the extracting, fitting, removing and adding steps for the remainder of the subsets of connected edges; and fitting the model to the data set, wherein the data set is indicative of the balloon catheter. Y1 - 2015 UR - https://patents.google.com/patent/US8989463B2/en ER - TY - GEN A1 - Schön, N. A1 - Blohm, L. A1 - Dannenmann, T. A1 - Dennerlein, F. A1 - Hoheisel, M. A1 - Strobel, Norbert T1 - Verfahren zur Registrierung eines ersten Koordinatensystems einer ersten medizinischen Bildgebungseinrichtung mit einem zweiten Koordinatensystemeiner zweitenmedizinischen Bildgebungseinrichtung und/oder einem dritten Koordinatensystem eines medizinischen Instruments, welches durchMarker einer medizinischen Navigationseinrichtung definiert ist, und medizinisches Untersuchungs- und/oder Behandlungssystem (Patent, DE 102011006537) Y1 - 2014 ER - TY - GEN A1 - Dennerlein, F. A1 - Blohm, L. A1 - Vogt, M. A1 - Hoheisel, M. A1 - Schön, N. A1 - Strobel, Norbert A1 - Dannenmann, T. T1 - Verfahren und System zur Unterstützung des Arbeitsablaufs in einer Operationsumgebung (Patent, DE102011006574) Y1 - 2014 ER - TY - CHAP A1 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Albarqouni, Shadi A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Learning-based X-ray image denoising utilizing model-based image simulations T2 - International Conference on Medical Image Computing and Computer-Assisted Intervention - MICCAI 2019, 22nd International Conference Shenzhen, China, October 13-17, 2019 Proceedings, Part VI Y1 - 2019 U6 - https://doi.org/10.1007/978-3-030-32226-7_61 SP - 549 EP - 557 PB - Springer International Publishing CY - Cham ER - TY - CHAP A1 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - DiNitto, Julie A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Model-based motion artifact correction in digital subtraction angiography using optical-flow T2 - Bildverarbeitung für die Medizin 2019: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 17. bis 19. März 2019 in Lübeck Y1 - 2019 U6 - https://doi.org/10.1007/978-3-658-25326-4_31 SP - 146 EP - 151 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Spieß, Florian A1 - Friesslich, Jonas A1 - Bluemm, Daniel A1 - Mast, Fabio A1 - Vinokour, Dmitrij A1 - Kounev, Samuel A1 - Kaupp, Tobias A1 - Strobel, Norbert T1 - Towards a Mobile Robot Localization Benchmark with Challenging Sensordata in an Industrial Environment T2 - 2021 20th International Conference on Advanced Robotics (ICAR) N2 - To arrive at a realistic assessment of localization methods in terms of their performance in an industrial environment under various challenging conditions, we provide a benchmark to evaluate algorithms both for individual components as well as multi-sensor systems. For several sensor types, including wheel odometry, RGB cameras, RGB-D cameras, and LIDAR, potential issues were identified. The accuracy of wheel odometry, for example, when there are bumps on the track. For each sensor type, we explicitly chose a track for the benchmark dataset containing situations where the sensor fails to provide adequate measurements. Based on the acquired sensor data, localization can be achieved either using a single sensor information or sensor fusion. To help evaluate the output of associated localization algorithms, we provide a software to evaluate a set of metrics as part of the paper. An example application of the benchmark with state-of-the-art algorithms for each sensor is also provided. Y1 - 2021 U6 - https://doi.org/10.1109/ICAR53236.2021.9659355 SP - 857 EP - 864 ER - TY - JOUR A1 - Spiess, Florian A1 - Reinhart, Lukas A1 - Strobel, Norbert A1 - Kaupp, Tobias A1 - Kaiser, Dennis A1 - Kounev, Samuel T1 - People detection with depth silhouettes and convolutional neural networks on a mobile robot JF - Journal of Image and Graphics N2 - This paper presents a novel people detection approach for mobile robot applications based on a combination of classical computer vision techniques and a state-of-the-art neural network. Our approach involves an RGB-D camera as an environmental sensor. The depth data is used to extract silhouettes around people. The RGB images are subsequently augmented with this border information before passing it to the neural network. Under challenging lighting conditions, our system was able to outperform the neural network trained on regular RGB data alone by a factor of two. Y1 - 2021 UR - http://www.joig.net/index.php?m=content&c=index&a=show&catid=72&id=277 VL - 9 IS - 4 SP - 135 EP - 139 ER - TY - CHAP A1 - Spiess, Florian A1 - Strobel, Norbert A1 - Kaupp, Tobias A1 - Kounev, Samuel T1 - A data-driven Sensor Model for LIDAR Range Measurements used for Mobile Robot Navigation T2 - 2022 Sixth IEEE International Conference on Robotic Computing (IRC) N2 - In this paper, an analysis of the precision of LIDAR range measurements is presented. LIDAR data from two different sensors (HLS-LFCD-LDS and SICK TIM561) were analyzed regarding the influence of range, incident angle to the surface, and material. Based on the results, a data-driven model for LIDAR precision behavior was developed, and a comparison with standard deviation models based on the vendor-provided specifications was presented. Our model can be used to create realistic sensor simulations and to develop robot navigation algorithms weighing sensor range readings based on the precision. Y1 - 2022 U6 - https://doi.org/10.1109/IRC55401.2022.00020 SP - 76 EP - 80 ER - TY - JOUR A1 - Spiess, Florian A1 - Friesslich, Jonas A1 - Kaupp, Tobias A1 - Kounev, Samuel A1 - Strobel, Norbert T1 - Survey and Experimental Comparison of RGB-D Indoor Robot Navigation Methods Supported by ROS and Their Expansion via Fusion with Wheel Odometry and IMU Data JF - International Journal of Mechanical Engineering and Robotics Research Y1 - 2020 U6 - https://doi.org/10.18178/ijmerr.9.12.1532-1540 VL - 9 IS - 12 SP - 1532 EP - 1540 ER - TY - JOUR A1 - Spiess, Florian A1 - Strobel, Norbert A1 - Kaupp, Tobias A1 - Kounev, Samuel T1 - A data-driven Model for Range Sensors JF - Encyclopedia with Semantic Computing and Robotic Intelligence Y1 - 2023 UR - https://www.worldscientific.com/doi/abs/10.1142/S2529737623500065?journalCode=escri ER - TY - CHAP A1 - Roser, Philipp A1 - Zhong, Xia A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Simultaneous estimation of X-ray back-scatter and forward-scatter using multi-task learning T2 - Medical Image Computing and Computer Assisted Intervention–MICCAI 2020: 23rd International Conference, Lima, Peru, October 4–8, 2020, Proceedings, Part II 23 Y1 - 2020 UR - https://link.springer.com/chapter/10.1007/978-3-030-59713-9_20 U6 - https://doi.org/10.1007/978-3-030-59713-9_20 SP - 199 EP - 208 PB - Springer International Publishing ER - TY - CHAP A1 - Zhong, Xia A1 - Roser, Philipp A1 - Bayer, Siming A1 - Ravikumar, Nishant A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Horz, Tim A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Pediatric Patient Surface Model Atlas Generation and X-Ray Skin Dose Estimation T2 - Bildverarbeitung für die Medizin 2019: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 17. bis 19. März 2019 in Lübeck Y1 - 2019 U6 - https://doi.org/10.1007/978-3-658-25326-4_27 SP - 122 EP - 127 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Deep scatter splines: Learning-based medical X-ray scatter estimation using B-splines T2 - The 6th International Conference on Image Formation in X-Ray Computed Tompgraphy Y1 - 2020 UR - https://arxiv.org/pdf/2005.03470.pdf ER - TY - CHAP A1 - Shetty, Karthik A1 - Birkhold, Annette A1 - Strobel, Norbert A1 - Egger, Bernhard A1 - Jaganathan, Srikrishna A1 - Kowarschik, Markus A1 - Maier, Andreas T1 - Deep Learning Compatible Differentiable X-ray Projections for Inverse Rendering T2 - Bildverarbeitung für die Medizin 2021: Proceedings, German Workshop on Medical Image Computing, Regensburg, March 7-9 Y1 - 2021 UR - https://arxiv.org/pdf/2102.02912.pdf SP - 290 EP - 295 PB - Springer Fachmedien CY - Wiesbaden ER - TY - CHAP A1 - Shetty, Karthik A1 - Birkhold, Annette A1 - Jaganathan, Srikrishna A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Maier, Andreas A1 - Egger, Bernhard T1 - PLIKS - A Pseudo-Linear Inverse Kinematic Solver for3D Human Body Estimation T2 - Proceedings of the IEEE/CVF Conference on Computer Vision and Pattern Recognition Y1 - 2023 UR - https://arxiv.org/pdf/2211.11734.pdf SP - 574 EP - 584 ER - TY - JOUR A1 - Hariharan, Sai Gokul A1 - Kaethner, Christian A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Robust learning-based x-ray image denoising—potential pitfalls, their analysis and solutions JF - Biomedical Physics & Engineering Express Y1 - 2022 U6 - https://doi.org/10.1088/2057-1976/ac3489 VL - 8 IS - 3 ER - TY - JOUR A1 - Maul, Noah A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Zhong, Xia A1 - Strobel, Norbert A1 - Maier, Andreas T1 - Learning-based occupational x-ray scatter estimation JF - Physics in Medicine and Biology Y1 - 2022 U6 - https://doi.org/10.1088/1361-6560/ac58dc VL - 67 IS - 7 ER - TY - JOUR A1 - Zhong, Xia A1 - Amrehn, Mario A1 - Ravikumar, Nishant A1 - Chen, Shuqing A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Deep action learning enables robust 3D segmentation of body organs in various CT and MRI images JF - Scientific Reports Y1 - 2021 U6 - https://doi.org/10.1038/s41598-021-82370-6 VL - 11 IS - 1 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Stimpel, Bernhard A1 - Syben, Christopher A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - Fully-automatic CT data preparation for interventional X-ray skin dose simulation JF - Bildverarbeitung für die Medizin 2020: Algorithmen - Systeme - Anwendungen. Proceedings des Workshops vom 15. bis 17. März 2020 in Berlin Y1 - 2020 U6 - https://doi.org/10.1007/978-3-658-29267-6_26 SP - 125 EP - 130 PB - Springer Fachmedien CY - Wiesbaden ER - TY - JOUR A1 - Busch, Erik A1 - Strobel, Norbert A1 - Nobach, Kai A1 - Bulitta, Clemens A1 - Hirshfeld, John W. A1 - Lin, Wu A1 - de Abreu, Marcel Gama T1 - Optimizing the innovation and development process of medical devices - a study based on angiographic equipment JF - Health and Technology Y1 - 2021 UR - https://link.springer.com/article/10.1007/s12553-021-00537-7 U6 - https://doi.org/doi.org/10.1007/s12553-021-00537-7 VL - 11 IS - 3 SP - 563 EP - 574 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Ochs, Philipp A1 - Stepina, Elizaveta A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - XDose: toward online cross-validation of experimental and computational X-ray dose estimation JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2020 U6 - https://doi.org/10.1007/s11548-020-02298-6 VL - 16 IS - 2 ER - TY - JOUR A1 - Roser, Philipp A1 - Birkhold, Annette A1 - Preuhs, Alexander A1 - Syben, Christopher A1 - Felsner, Lina A1 - Hoppe, Elisabeth A1 - Strobel, Norbert A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - X-ray Scatter Estimation Using Deep Splines JF - IEEE Transactions on Medical Imaging Y1 - 2021 UR - https://arxiv.org/pdf/2101.09177.pdf VL - 40 IS - 9 SP - 2272 EP - 2283 ER - TY - JOUR A1 - Hariharan, Sai Gokul A1 - Strobel, Norbert A1 - Kaethner, Christian A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Navab, Nassir T1 - Data-driven estimation of noise variance stabilization parameters for low-dose x-ray images JF - Physics in Medicine and Biology Y1 - 2020 U6 - https://doi.org/10.1088/1361-6560/abbc82 VL - 65 IS - 22 ER - TY - JOUR A1 - Zhong, Xia A1 - Strobel, Norbert A1 - Birkhold, Annette A1 - Kowarschik, Markus A1 - Fahrig, Rebecca A1 - Maier, Andreas T1 - A machine learning pipeline for internal anatomical landmark embedding based on a patient surface model JF - International Journal of Computer Assisted Radiology and Surgery Y1 - 2019 U6 - https://doi.org/10.1007/s11548-018-1871-y VL - 14 IS - 1 SP - 53 EP - 61 ER - TY - JOUR A1 - Shetty, Karthik A1 - Birkhold, Annette A1 - Jaganathan, Srikrishna A1 - Strobel, Norbert A1 - Egger, Bernhard A1 - Kowarschik, Markus A1 - Maier, Andreas T1 - BOSS: Bones, organs and skin shape model JF - Computers in Biology and Medicine Y1 - 2023 UR - https://arxiv.org/pdf/2303.04923.pdf SN - 0010-4825 VL - 165 ER -