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Franz Leberl

Graz University of Technology, Computer Science and Biomedical Engineering, Emeritus

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Matthew J Weait

University of Oxford

School of the Art Institute of Chicago

Thomas Armstrong

University of St. Gallen

Pompeu Fabra University

Duke University

San Diego State University

José d'Encarnação

Universidade de Coimbra

Julien G.R. Vincent

Université Paris 1 - Panthéon-Sorbonne

Alfitri Alfitri

IAIN SAMARINDA

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Papers by Franz Leberl

Automated matching experiments with different kinds of SAR imagery

by Franz Leberl and G. Paar

IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium, 1996

Automated Matching Experiments with Different Kinds of SAR Imagery M. Gelautz ', G. Jakoib &... more

AUTOMATIC FUSION OF PARTIAL RECONSTRUCTIONS

ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences, 2012

Novel image acquisition tools such as micro aerial vehicles (MAVs) in form of quad-or octo-rotor ... more Novel image acquisition tools such as micro aerial vehicles (MAVs) in form of quad-or octo-rotor helicopters support the creation of 3D reconstructions with ground sampling distances below 1 cm. The limitation of aerial photogrammetry to nadir and oblique views in heights of several hundred meters is bypassed, allowing close-up photos of facades and ground features. However, the new acquisition modality also introduces challenges: First, flight space might be restricted in urban areas, which leads to missing views for accurate 3D reconstruction and causes fracturing of large models. This could also happen due to vegetation or simply a change of illumination during image acquisition. Second, accurate geo-referencing of reconstructions is difficult because of shadowed GPS signals in urban areas, so alignment based on GPS information is often not possible. In this paper, we address the automatic fusion of such partial reconstructions. Our approach is largely based on the work of (Wendel et al., 2011a), but does not require an overhead digital surface model for fusion. Instead, we exploit that patch-based semi-dense reconstruction of the fractured model typically results in several point clouds covering overlapping areas, even if sparse feature correspondences cannot be established. We approximate orthographic depth maps for the individual parts and iteratively align them in a global coordinate system. As a result, we are able to generate point clouds which are visually more appealing and serve as an ideal basis for further processing. Mismatches between parts of the fused models depend only on the individual point density, which allows us to achieve a fusion accuracy in the range of ±1 cm on our evaluation dataset.

Multiresolution texture for photorealistic rendering

by Franz Leberl and H. Mayer

Proceedings Spring Conference on Computer Graphics, 2001

This paper presents a method to automatically calculate texture maps for a given 3-dimensional ob... more This paper presents a method to automatically calculate texture maps for a given 3-dimensional object out of a sequence of images. It is used in our image-based modeling approach after the registration of the images and the geometric modeling is done. We show, that the presented method uses the information from all images by implicitly applying a weighting function. Using this approach the consideration of modeled occlusions as well as the detection and removal of non-modeled occlusions is accomplished. The final resolution of the texture maps can be adjusted on a pixel/cm basis.

Collection, Processing and Augmentation of VR Cities

The starting point for the modeling of urban spaces was in the mid-1990s, using semi-manual aeria... more The starting point for the modeling of urban spaces was in the mid-1990s, using semi-manual aerial stereo- photogrammetric methods, also multi-view street-level image streams and at times also single images. First tangible applications of such 3D models were found in the late 1990's in the telecom-industry for the study of signal propagation of cellular and other telecommunication technologies. We now

High Quality Photogrammetric Scanning for Mapping

Scanning of analog images has become the new key hardware technology specific to modern digital p... more Scanning of analog images has become the new key hardware technology specific to modern digital photogrammetry. Since specialized photogrammetric scanners have been introduced we observe a gradual development and enhancement of quality of the resulting scans. Originally, geometric accuracy of scanners was the overriding specification for these products. This is increasingly being augmented by a concern for good color and

3D-models of the Human Habitat for the Internet

Computer Vision Theory and Applications, 2009

The Internet has inspired an enormous appetite for 3-dimensional geo-data of the urban environmen... more The Internet has inspired an enormous appetite for 3-dimensional geo-data of the urban environment to support location-aware applications. This has in fact become the surprising "killer application" of such 3-dimensional data. In March 2005, at the occasion of his 50th birthday, Bill Gates went public with his "Virtual Earth Vision" for local search in the Internet and stated: "You'll be walking around in downtown London and be able to see the shops, the stores, see what the traffic is like. Walk in a shop and navigate the merchandise. Not in the flat, 2D interface that we have on the web today, but in a virtual reality walkthrough."

Computer Aided Liver Surgery Planning Based on Augmented Reality Techniques

by Franz Leberl and A. Bornik

Bildverarbeitung fur die Medizin, 2003

ULTRACAM-D: Understanding some Noteworthy Capabilities1

Digital aerial photogrammetric cameras are taking over with a vengeance. While by the end of 2002... more Digital aerial photogrammetric cameras are taking over with a vengeance. While by the end of 2002, there were only 6 such cameras in use globally, this increased to 16 in 2003, to 50 in 2004 and may exceed 100 in 2005. By the end of 2006, more photogrammetric coverage might be produced digitally than via film. Given this rapid change

Multiple Image SAR Shape-from-Shading

FAST ON-SITE RECONSTRUCTION AND VISUALIZATION OF ARCHAEOLOGICAL FINDS

We report on a study carried out within the 3D MURALE project, in which the complete workflow nec... more We report on a study carried out within the 3D MURALE project, in which the complete workflow necessary for automatic recording, reconstruction and interactive visualization of artefacts on archaeological excavation sites has been tested. With state-of-the-art technologies from digital photogrammetry, computer vision and computer graphics a prototypical pipeline for recording, 3D modeling and visualization of archaeological artefacts has been implemented

Aerial Photo Building Classification by Stacking Appearance and Elevation Measurements

Remote Sensing is trending towards the use of greater detail of its source data, advancing from e... more Remote Sensing is trending towards the use of greater detail of its source data, advancing from ever better resolving satellite imagery via decimeter-type aerial photography towards centimeter-level street-side data. It also is taking advantage of an increase in methodological sophistication, greatly supported by rapid progress of the available computing environment. The location awareness of the Internet furthermore demonstrates that large area remote sensing strives for a model of human scale detail. This paper addresses the task of mapping entire urban areas, where objects to be mapped are naturally three dimensional. Specifically we are introducing a novel approach for the segmentation and classification of buildings from aerial images at the level of pixels. Buildings are complex 3D objects which are usually represented by features of different modalities, i.e. visual information and 3D height data. The idea is to treat them in separated processes for learning and then integrat...

Flying the New Large Format Digital Aerial Camera Ultracam

The race to replace the aerial film camera started in July 2000 with the product announcements of... more The race to replace the aerial film camera started in July 2000 with the product announcements of the ADS-40 by LH- Systems (now Leica Geosystems) and of the DMC by Z/I Imaging. Recently, the UltraCam-D was introduced. This is a 90 Mpixel large format aerial camera by Vexcel Imaging to add an innovative offering with a focus on a on-on-one

Automated Tracking of Arctic Ice Floes in Multitemporal Sar Imagery

12th Canadian Symposium on Remote Sensing Geoscience and Remote Sensing Symposium,, 1989

We discuss the use of two algorithms to per form shape matching on the boundaries of ice floes i... more We discuss the use of two algorithms to per form shape matching on the boundaries of ice floes in SAR images in order to produce an ice motion map. The algorithms match a shape descriptor known as the psi-s curve. The first algorithm uses normalized correlation to match the psi-s curves, while the second uses dynamic programming to compute an

Virtual Habitat: models of the urban outdoors

City models with building exteriors, some interior spaces, vegetation, addresses and phototexture... more City models with building exteriors, some interior spaces, vegetation, addresses and phototexture are of growing interest. Our work is the result of an Austrian national research program within the framework of Virtual Reality and Visualization. We describe a data collection system for buildings, a data modeling and visualization component.

Leberchirurgische Operationsplanung unter Verwendung der "Augmented Reality

Workstation Requirements For An EOS-oriented

International Geoscience and Remote Sensing Symposium, 'Remote Sensing: Moving Toward the 21st Century'., 1988

ibis vision of an EDS, informtion system which We discuss the initial efforts for the coordinates... more ibis vision of an EDS, informtion system which We discuss the initial efforts for the coordinates the distribution of EDS data suggests determination of functional and performance a requirement for a workstation which all- the requirements of a workstation specifically individual scientific user convenient access and directed tmrd scientific users of the proposed interaction with such a system (see Figs.

Computer aided liver surgery planning based on augmented reality techniques

Proceedings of the 2001 conference on Virtual reality, archeology, and cultural heritage - VAST '01, 2001

This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Eur... more This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Europe system (3D MURALE). It consists of a set of tools for recording, reconstructing, encoding, visualising and database searching/querying that operate on buildings, building parts, statues, statue parts, pottery, stratigraphy, terrain geometry and texture and material texture. The tools are loosely linked together by a common database on which they all have the facility to store and access data. The paper describes the overall architecture of the 3D MURALE system and then briefly describes the functionality of the tools provided by the project. The paper compares the multimedia studio architecture adopted in this project with other multimedia studio architectures.

<title>Computer-aided liver surgery planning: an augmented reality approach</title>

Medical Imaging 2003: Visualization, Image-Guided Procedures, and Display, 2003

Surgical resection of liver tumors requires a detailed three-dimensional understanding of a compl... more Surgical resection of liver tumors requires a detailed three-dimensional understanding of a complex arrangement of vasculature, liver segments and tumors inside the liver. In most cases, surgeons need to develop this understanding by looking at sequences of axial images from modalities like X-ray computed tomography. A system for liver surgery planning is reported that enables physicians to visualize and refine segmented input liver data sets, as well as to simulate and evaluate different resections plans. The system supports surgeons in finding the optimal treatment strategy for each patient and eases the data preparation process. The use of augmented reality contributes to a user-friendly design and simplifies complex interaction with 3D objects. The main function blocks developed so far are: basic augmented reality environment, user interface, rendering, surface reconstruction from segmented volume data sets, surface manipulation and quantitative measurement toolkit. The flexible design allows to add functionality via plug-ins. First practical evaluation steps have shown a good acceptance. Evaluation of the system is ongoing and future feedback from surgeons will be collected and used for design refinements.

Augmented-reality-based liver-surgical planning system

European Surgery, 2004

ABSTRACT BACKGROUND: The preoperative planning of liver resections is commonly based on two-dimen... more ABSTRACT BACKGROUND: The preoperative planning of liver resections is commonly based on two-dimensional imaging techniques such as sonography, computed tomography (CT), and magnetic resonance imaging. The operability of liver tumors depends on the three-dimensional relation of the parenchyma to be resected to the intrahepatic vascular structures which define the autonomously functioning liver segments. Our aim was to establish a liver surgery planning system (LSPS) for major liver resections by augmented-reality (AR) techniques for the accurate evaluation of operability. METHODS: The system provides methods for the processing and preparation of the input CT data, three-dimensional visualization, and resection planning. The output consists of quantitative indices (e.g., volume of liver tumors or segments) and an elaborated plan for the surgical procedure including information like the number of liver segments subject to resection and their spatial arrangement or the volume of the remaining or the removed liver tissue. Basically, the LSPS comprises two main components, a medical image analysis and an AR system. The medical image analysis part is responsible for the segmentation of the liver, the vascular structures, and the tumors and for liver segment approximation. The AR system is utilized for visualization and various kinds of user interaction. RESULTS: Experiments with anonymized CT data sets demonstrated the ability of surgeons to deal with different tasks in resection planning after a brief introduction. This led also to a high acceptance by colleagues who wanted to get information for their surgical strategy as quickly as possible. CONCLUSIONS: Quantitative measurements are of major importance for the planning of liver resections, for which precise measurements of distances and volumes are required. On the basis of the patient&#39;s CT dataset, the LSPS supports an effective way to find the optimal surgical strategy for each patient. The flexible design of this system allows the addition of functionality via plug-ins. Furthermore, an expansion of the developed core system for intraoperative applications is possible and provides the advantage of having one platform for planning and support during surgery. GRUNDLAGEN: Die Planung großer Leberresektionen stützt sich normalerweise auf die Ergebnisse bildgebender diagnostischer Verfahren wie Sonographie, Computertomographie (CT) oder Magnetresonanztomographie. Die Operabilität von Lebertumoren hängt wesentlich ab von ihrer Beziehung zu den intrahepatischen Gefäßsystemen, welche die einzelnen Lebersegmente definieren. Unser Ziel war die Entwicklung eines leberchirurgischen Planungssystems, welches die genaue Überprüfung der Operabilität sowie die chirurgische Resektionsplanung unter Verwendung der &quot;Augmented Reality&quot; (AR) ermöglicht. METHODIK: Das System bereitet die eingehenden CT-Datensätze auf und stellt eine stereoskopische dreidimensionale Visualisierung und Resektionsplanung zur Verfügung. Der Output besteht einerseits aus quantitativen Parametern, wie z. B. dem Tumorvolumen oder den Segmentvolumina, und andererseits in einer Resektionsplanung unter Anzeige der zu entfernenden Segmente (deren Anzahl und Volumen oder das Volumen der Restleber). Grundsätzlich besteht das Planungssystem aus 2 Hauptkomponenten, einem medizinischen Bildanalysesystem und einem Augmented-Reality-System. Im medizinischen Bildanalysesystem wird die Segmentierung der Leber, des intrahepatischen Gefäßsystems sowie des Tumors durchgeführt. Im Augmented-Reality-System werden die Ergebnisse visualisiert und die Benutzerinteraktion ermöglicht. ERGEBNISSE: Experimente mit anonymisierten CT-Datensätzen haben gezeigt, dass die Chirurgen nach einer kurzen Vorstellung des Systems in der Lage waren, verschiedene Fragestellungen bei der Resektionsplanung erfolgreich zu lösen. Dies führte zu einer hohen Akzeptanz bei Kollegen, die möglichst rasch zusätzliche Informationen für ihre Operationsplanung benötigen. SCHLUSSFOLGERUNGEN: In der Planung leberchirurgischer Eingriffe sind quantitative Messungen (Volumen und Distanzen) von hoher Wichtigkeit. Auf Basis von aktuellen CT-Datensätzen stellt das leberchirurgische Planungssystem ein effektives Werkzeug dar, die beste chirurgische Strategie für jeden Patienten zu finden. Durch das flexible Design sind Funktionserweiterungen durch Plug-ins möglich. Darüber hinaus ist eine Erweiterung der Kernfunktionalität durch intraoperativ nutzbare Applikationen möglich, sodass eine Plattform zur Planung bis hin zur intraoperativen Unterstützung zur Verfügung steht.

Automated matching experiments with different kinds of SAR imagery

by Franz Leberl and G. Paar

IGARSS '96. 1996 International Geoscience and Remote Sensing Symposium, 1996

Automated Matching Experiments with Different Kinds of SAR Imagery M. Gelautz ', G. Jakoib &... more

AUTOMATIC FUSION OF PARTIAL RECONSTRUCTIONS

ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences, 2012

Novel image acquisition tools such as micro aerial vehicles (MAVs) in form of quad-or octo-rotor ... more Novel image acquisition tools such as micro aerial vehicles (MAVs) in form of quad-or octo-rotor helicopters support the creation of 3D reconstructions with ground sampling distances below 1 cm. The limitation of aerial photogrammetry to nadir and oblique views in heights of several hundred meters is bypassed, allowing close-up photos of facades and ground features. However, the new acquisition modality also introduces challenges: First, flight space might be restricted in urban areas, which leads to missing views for accurate 3D reconstruction and causes fracturing of large models. This could also happen due to vegetation or simply a change of illumination during image acquisition. Second, accurate geo-referencing of reconstructions is difficult because of shadowed GPS signals in urban areas, so alignment based on GPS information is often not possible. In this paper, we address the automatic fusion of such partial reconstructions. Our approach is largely based on the work of (Wendel et al., 2011a), but does not require an overhead digital surface model for fusion. Instead, we exploit that patch-based semi-dense reconstruction of the fractured model typically results in several point clouds covering overlapping areas, even if sparse feature correspondences cannot be established. We approximate orthographic depth maps for the individual parts and iteratively align them in a global coordinate system. As a result, we are able to generate point clouds which are visually more appealing and serve as an ideal basis for further processing. Mismatches between parts of the fused models depend only on the individual point density, which allows us to achieve a fusion accuracy in the range of ±1 cm on our evaluation dataset.

Multiresolution texture for photorealistic rendering

by Franz Leberl and H. Mayer

Proceedings Spring Conference on Computer Graphics, 2001

This paper presents a method to automatically calculate texture maps for a given 3-dimensional ob... more This paper presents a method to automatically calculate texture maps for a given 3-dimensional object out of a sequence of images. It is used in our image-based modeling approach after the registration of the images and the geometric modeling is done. We show, that the presented method uses the information from all images by implicitly applying a weighting function. Using this approach the consideration of modeled occlusions as well as the detection and removal of non-modeled occlusions is accomplished. The final resolution of the texture maps can be adjusted on a pixel/cm basis.

Collection, Processing and Augmentation of VR Cities

The starting point for the modeling of urban spaces was in the mid-1990s, using semi-manual aeria... more The starting point for the modeling of urban spaces was in the mid-1990s, using semi-manual aerial stereo- photogrammetric methods, also multi-view street-level image streams and at times also single images. First tangible applications of such 3D models were found in the late 1990's in the telecom-industry for the study of signal propagation of cellular and other telecommunication technologies. We now

High Quality Photogrammetric Scanning for Mapping

Scanning of analog images has become the new key hardware technology specific to modern digital p... more Scanning of analog images has become the new key hardware technology specific to modern digital photogrammetry. Since specialized photogrammetric scanners have been introduced we observe a gradual development and enhancement of quality of the resulting scans. Originally, geometric accuracy of scanners was the overriding specification for these products. This is increasingly being augmented by a concern for good color and

3D-models of the Human Habitat for the Internet

Computer Vision Theory and Applications, 2009

The Internet has inspired an enormous appetite for 3-dimensional geo-data of the urban environmen... more The Internet has inspired an enormous appetite for 3-dimensional geo-data of the urban environment to support location-aware applications. This has in fact become the surprising "killer application" of such 3-dimensional data. In March 2005, at the occasion of his 50th birthday, Bill Gates went public with his "Virtual Earth Vision" for local search in the Internet and stated: "You'll be walking around in downtown London and be able to see the shops, the stores, see what the traffic is like. Walk in a shop and navigate the merchandise. Not in the flat, 2D interface that we have on the web today, but in a virtual reality walkthrough."

Computer Aided Liver Surgery Planning Based on Augmented Reality Techniques

by Franz Leberl and A. Bornik

Bildverarbeitung fur die Medizin, 2003

ULTRACAM-D: Understanding some Noteworthy Capabilities1

Digital aerial photogrammetric cameras are taking over with a vengeance. While by the end of 2002... more Digital aerial photogrammetric cameras are taking over with a vengeance. While by the end of 2002, there were only 6 such cameras in use globally, this increased to 16 in 2003, to 50 in 2004 and may exceed 100 in 2005. By the end of 2006, more photogrammetric coverage might be produced digitally than via film. Given this rapid change

Multiple Image SAR Shape-from-Shading

FAST ON-SITE RECONSTRUCTION AND VISUALIZATION OF ARCHAEOLOGICAL FINDS

We report on a study carried out within the 3D MURALE project, in which the complete workflow nec... more We report on a study carried out within the 3D MURALE project, in which the complete workflow necessary for automatic recording, reconstruction and interactive visualization of artefacts on archaeological excavation sites has been tested. With state-of-the-art technologies from digital photogrammetry, computer vision and computer graphics a prototypical pipeline for recording, 3D modeling and visualization of archaeological artefacts has been implemented

Aerial Photo Building Classification by Stacking Appearance and Elevation Measurements

Remote Sensing is trending towards the use of greater detail of its source data, advancing from e... more Remote Sensing is trending towards the use of greater detail of its source data, advancing from ever better resolving satellite imagery via decimeter-type aerial photography towards centimeter-level street-side data. It also is taking advantage of an increase in methodological sophistication, greatly supported by rapid progress of the available computing environment. The location awareness of the Internet furthermore demonstrates that large area remote sensing strives for a model of human scale detail. This paper addresses the task of mapping entire urban areas, where objects to be mapped are naturally three dimensional. Specifically we are introducing a novel approach for the segmentation and classification of buildings from aerial images at the level of pixels. Buildings are complex 3D objects which are usually represented by features of different modalities, i.e. visual information and 3D height data. The idea is to treat them in separated processes for learning and then integrat...

Flying the New Large Format Digital Aerial Camera Ultracam

The race to replace the aerial film camera started in July 2000 with the product announcements of... more The race to replace the aerial film camera started in July 2000 with the product announcements of the ADS-40 by LH- Systems (now Leica Geosystems) and of the DMC by Z/I Imaging. Recently, the UltraCam-D was introduced. This is a 90 Mpixel large format aerial camera by Vexcel Imaging to add an innovative offering with a focus on a on-on-one

Automated Tracking of Arctic Ice Floes in Multitemporal Sar Imagery

12th Canadian Symposium on Remote Sensing Geoscience and Remote Sensing Symposium,, 1989

We discuss the use of two algorithms to per form shape matching on the boundaries of ice floes i... more We discuss the use of two algorithms to per form shape matching on the boundaries of ice floes in SAR images in order to produce an ice motion map. The algorithms match a shape descriptor known as the psi-s curve. The first algorithm uses normalized correlation to match the psi-s curves, while the second uses dynamic programming to compute an

Virtual Habitat: models of the urban outdoors

City models with building exteriors, some interior spaces, vegetation, addresses and phototexture... more City models with building exteriors, some interior spaces, vegetation, addresses and phototexture are of growing interest. Our work is the result of an Austrian national research program within the framework of Virtual Reality and Visualization. We describe a data collection system for buildings, a data modeling and visualization component.

Leberchirurgische Operationsplanung unter Verwendung der "Augmented Reality

Workstation Requirements For An EOS-oriented

International Geoscience and Remote Sensing Symposium, 'Remote Sensing: Moving Toward the 21st Century'., 1988

ibis vision of an EDS, informtion system which We discuss the initial efforts for the coordinates... more ibis vision of an EDS, informtion system which We discuss the initial efforts for the coordinates the distribution of EDS data suggests determination of functional and performance a requirement for a workstation which all- the requirements of a workstation specifically individual scientific user convenient access and directed tmrd scientific users of the proposed interaction with such a system (see Figs.

Computer aided liver surgery planning based on augmented reality techniques

Proceedings of the 2001 conference on Virtual reality, archeology, and cultural heritage - VAST '01, 2001

This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Eur... more This paper introduces the 3D Measurement and Virtual Reconstruction of Ancient Lost Worlds of Europe system (3D MURALE). It consists of a set of tools for recording, reconstructing, encoding, visualising and database searching/querying that operate on buildings, building parts, statues, statue parts, pottery, stratigraphy, terrain geometry and texture and material texture. The tools are loosely linked together by a common database on which they all have the facility to store and access data. The paper describes the overall architecture of the 3D MURALE system and then briefly describes the functionality of the tools provided by the project. The paper compares the multimedia studio architecture adopted in this project with other multimedia studio architectures.

<title>Computer-aided liver surgery planning: an augmented reality approach</title>

Medical Imaging 2003: Visualization, Image-Guided Procedures, and Display, 2003

Surgical resection of liver tumors requires a detailed three-dimensional understanding of a compl... more Surgical resection of liver tumors requires a detailed three-dimensional understanding of a complex arrangement of vasculature, liver segments and tumors inside the liver. In most cases, surgeons need to develop this understanding by looking at sequences of axial images from modalities like X-ray computed tomography. A system for liver surgery planning is reported that enables physicians to visualize and refine segmented input liver data sets, as well as to simulate and evaluate different resections plans. The system supports surgeons in finding the optimal treatment strategy for each patient and eases the data preparation process. The use of augmented reality contributes to a user-friendly design and simplifies complex interaction with 3D objects. The main function blocks developed so far are: basic augmented reality environment, user interface, rendering, surface reconstruction from segmented volume data sets, surface manipulation and quantitative measurement toolkit. The flexible design allows to add functionality via plug-ins. First practical evaluation steps have shown a good acceptance. Evaluation of the system is ongoing and future feedback from surgeons will be collected and used for design refinements.

Augmented-reality-based liver-surgical planning system

European Surgery, 2004

ABSTRACT BACKGROUND: The preoperative planning of liver resections is commonly based on two-dimen... more ABSTRACT BACKGROUND: The preoperative planning of liver resections is commonly based on two-dimensional imaging techniques such as sonography, computed tomography (CT), and magnetic resonance imaging. The operability of liver tumors depends on the three-dimensional relation of the parenchyma to be resected to the intrahepatic vascular structures which define the autonomously functioning liver segments. Our aim was to establish a liver surgery planning system (LSPS) for major liver resections by augmented-reality (AR) techniques for the accurate evaluation of operability. METHODS: The system provides methods for the processing and preparation of the input CT data, three-dimensional visualization, and resection planning. The output consists of quantitative indices (e.g., volume of liver tumors or segments) and an elaborated plan for the surgical procedure including information like the number of liver segments subject to resection and their spatial arrangement or the volume of the remaining or the removed liver tissue. Basically, the LSPS comprises two main components, a medical image analysis and an AR system. The medical image analysis part is responsible for the segmentation of the liver, the vascular structures, and the tumors and for liver segment approximation. The AR system is utilized for visualization and various kinds of user interaction. RESULTS: Experiments with anonymized CT data sets demonstrated the ability of surgeons to deal with different tasks in resection planning after a brief introduction. This led also to a high acceptance by colleagues who wanted to get information for their surgical strategy as quickly as possible. CONCLUSIONS: Quantitative measurements are of major importance for the planning of liver resections, for which precise measurements of distances and volumes are required. On the basis of the patient&#39;s CT dataset, the LSPS supports an effective way to find the optimal surgical strategy for each patient. The flexible design of this system allows the addition of functionality via plug-ins. Furthermore, an expansion of the developed core system for intraoperative applications is possible and provides the advantage of having one platform for planning and support during surgery. GRUNDLAGEN: Die Planung großer Leberresektionen stützt sich normalerweise auf die Ergebnisse bildgebender diagnostischer Verfahren wie Sonographie, Computertomographie (CT) oder Magnetresonanztomographie. Die Operabilität von Lebertumoren hängt wesentlich ab von ihrer Beziehung zu den intrahepatischen Gefäßsystemen, welche die einzelnen Lebersegmente definieren. Unser Ziel war die Entwicklung eines leberchirurgischen Planungssystems, welches die genaue Überprüfung der Operabilität sowie die chirurgische Resektionsplanung unter Verwendung der &quot;Augmented Reality&quot; (AR) ermöglicht. METHODIK: Das System bereitet die eingehenden CT-Datensätze auf und stellt eine stereoskopische dreidimensionale Visualisierung und Resektionsplanung zur Verfügung. Der Output besteht einerseits aus quantitativen Parametern, wie z. B. dem Tumorvolumen oder den Segmentvolumina, und andererseits in einer Resektionsplanung unter Anzeige der zu entfernenden Segmente (deren Anzahl und Volumen oder das Volumen der Restleber). Grundsätzlich besteht das Planungssystem aus 2 Hauptkomponenten, einem medizinischen Bildanalysesystem und einem Augmented-Reality-System. Im medizinischen Bildanalysesystem wird die Segmentierung der Leber, des intrahepatischen Gefäßsystems sowie des Tumors durchgeführt. Im Augmented-Reality-System werden die Ergebnisse visualisiert und die Benutzerinteraktion ermöglicht. ERGEBNISSE: Experimente mit anonymisierten CT-Datensätzen haben gezeigt, dass die Chirurgen nach einer kurzen Vorstellung des Systems in der Lage waren, verschiedene Fragestellungen bei der Resektionsplanung erfolgreich zu lösen. Dies führte zu einer hohen Akzeptanz bei Kollegen, die möglichst rasch zusätzliche Informationen für ihre Operationsplanung benötigen. SCHLUSSFOLGERUNGEN: In der Planung leberchirurgischer Eingriffe sind quantitative Messungen (Volumen und Distanzen) von hoher Wichtigkeit. Auf Basis von aktuellen CT-Datensätzen stellt das leberchirurgische Planungssystem ein effektives Werkzeug dar, die beste chirurgische Strategie für jeden Patienten zu finden. Durch das flexible Design sind Funktionserweiterungen durch Plug-ins möglich. Darüber hinaus ist eine Erweiterung der Kernfunktionalität durch intraoperativ nutzbare Applikationen möglich, sodass eine Plattform zur Planung bis hin zur intraoperativen Unterstützung zur Verfügung steht.