Marcus Goetz

Formal definition of a user-adaptive and length-optimal routing graph for complex indoor environments

Car routing solutions are omnipresent and solutions for pedestrians also exist. Furthermore, public or commercial buildings are getting bigger and the complexity of their internal structure has increased. Consequently, the need for indoor routing solutions has emerged. Some prototypes are available, but they still lack semantically-enriched modelling (e.g., access constraints, labels, etc.) and are not suitable for providing user-adaptive length-optimal routing in complex buildings. Previous approaches consider simple rooms, concave rooms, and corridors, but important characteristics such as distinct areas in huge rooms and solid obstacles inside rooms are not considered at all, although such details can increase navigation accuracy. By formally defining a weighted indoor routing graph, it is possible to create a detailed and user-adaptive model for route computation. The defined graph also contains semantic information such as room labels, door accessibility constraints, etc. Furthermore, one-way paths inside buildings are considered, as well as three-dimensional building parts, e.g., elevators or stairways. A hierarchical structure is also possible with the presented graph model.

Towards generating highly detailed 3D CityGML models from OpenStreetMap

About one decade has passed since US vice president Al Gore articulated his vision of Digital Earth (DE). Within this decade, a global multi-resolution and three-dimensional (3D) representation of the Earth, which sums up the DE vision, increasingly gained interest in both public and science. Due to the desired high resolution of the available data, highly detailed 3D city models comprise a huge part of DE and they are becoming an essential and useful tool for a range of different applications. In the past as well as at present, 3D models normally come from a range of different sources generated by professionals, such as laser scans or photogrammetry combined with 2D cadaster data. Some models are generated with semi-automated or fully automated approaches, but in most cases manual fine tuning or even manual construction from architectural plans is required. Further beyond outdoor city models, DE additionally envisages the provision of indoor information. That is, the interior structure of public or publically accessible buildings, such as airports or shopping malls, is represented and made available in 3D; however, at the moment, such models are mostly created by hand and essentially based on professional data sources. In contrast to such professional data, which is mainly captured by surveyors or companies, the last few years revealed the phenomenon of crowdsourced geodata, which receives an increasing attractiveness as an alternative data source for many Geographic Information Systems (GIS). Former research already demonstrated the power and richness of such geodata – especially OpenStreetMap (OSM) – and it has also been proved that this non-standardized, crowdsourced geodata can be combined with international standards of the Open Geospatial Consortium (OGC). For example, CityGML Level-of-Detail 1 (LoD1) and LoD2 models have already been created automatically from OSM. The research presented in this article will further continue on the automated generation of CityGML models from OpenStreetMap. Essentially, a method for the creation of highly detailed CityGML LoD4 models with interior structures will be explained. By applying the invented approach on existing OSM data, limitations and restrictions of the IndoorOSM mapping proposal, the available data and the developed approach are revealed and discussed.

Towards Defining a Framework for the Automatic Derivation of 3D CityGML Models from Volunteered Geographic Information

High-quality geographic data sources are eminent for urban data management and the creation of detailed 3D city models. In the past two decades, Volunteered Geographic Information (VGI) increasingly gained attractiveness to both amateur users and professionals, resulting in a broad availability of urban data within VGI communities and especially OpenStreetMap (OSM). OSM provides detailed information about urban regions and more buildings are also mapped. Existing 3D-VGI applications, e.g., KOSMOS Worldflier (Brejc, 2011) or the OSM-3D project (OSM-3D, 2011) only focus on visualization purposes, but a standardized usage for exchanging and sharing urban city models is not combined with VGI. Therefore, this paper presents a framework for an automatic VGI-based creation of 3D building models encoded as standardized CityGML models. The usage of VGI as a proper data source for the creation of standardized city models will be proven.

Using Crowdsourced Indoor Geodata for the Creation of a Three-Dimensional Indoor Routing Web Application

Routing services for outdoor areas are omnipresent and also three-dimensional (3D) visualization is quite common within this area. Recent research efforts are now trying to adapt well known outdoor routing services to complex indoor environments. However, most of the current indoor routing systems only focus on two-dimensional visualization, thus only one level can be depicted. Especially multi-level routes therefore lack visualization. Also, most of the (few) existing 3D indoor routing services utilize proprietary software or plugins, thus a widespread accessibility for those services by using common computers or mobile devices is not feasible. Therefore this paper describes the development of a web-based 3D routing system based on a new HTML extension. The visualization of rooms as well as the computed routes is realized with XML3D. Since this emerging technology is based on WebGL and will likely be integrated into the HTML5 standard, the developed system is already compatible with most common browsers such as Google Chrome or Firefox. Another key difference of the approach presented in this paper is that all utilized data is actually crowdsourced geodata from OpenStreetMap (OSM). Such data is collaboratively collected by both amateurs and professionals and can be used at no charge under the Open Data Commons Open Database License (ODbL). Our research combines user-generated geo content of the Web 2.0 with future Internet technology for the provision of a ubiquitously accessible 3D indoor routing application.

Optical needle endoscope for safe and precise stereotactically guided biopsy sampling in neurosurgery

Proper treatment of deep seated brain tumors requires correct histological diagnosis which unambiguously necessitates biopsy sampling. Stereotactically guided sampling of biopsies is widely used but bears the danger of incorrect sampling locations and damage to intracerebral blood vessels. Here, we present a minimally invasive contact endoscopic probe that can be inserted into the tissue inside a standard biopsy needle and allows for fluorescence detection of both tumorous tissue and intracerebral blood vessels. Outer diameter of our contact probe is smaller than 1.5 mm, field-of-view in the range of several hundred microns; the optical design allows for simultaneous detection and visualization of tissue autofluorescence and selective fluorescence signals from deep seated brain tumors and vasculature as shown on in vivo animal models. We demonstrate the tumor detection capability during stereotactic needle insertion in a clinical pilot trial. Using our probe, we expect stereotactic interventions to become safer and more precise and the technology might ultimately be used also for various other kinds of applications.

The Evolution of Geo-Crowdsourcing: Bringing Volunteered Geographic Information to the Third Dimension

Volunteered geographic information (VGI) describes the collaborative and voluntary collection of any kind of spatial data, and has evolved to become an important source for geo-information. Users participate in VGI communities and share their data with other community members at no charge. The data is based on personal measurements or personal knowledge, as well as on available aerial imagery provided by Bing Maps etc. In the early beginnings, VGI comprised only two-dimensional (2D) data, but now more and more users also contribute 3D-compliant data such as height information. By utilizing such 3D information or 3D-VGI, it is possible to create virtual but increasingly realistic 3D map features and models that can be compared to products such as Google Earth. In this chapter, the evolution of VGI from 2D to 3D is discussed. In particular, the creation of a 3D virtual globe including visualization of 3D building models as well as traffic infrastructure, landuse areas, and points of interest (POIs) is reviewed. Additional data sources and the semantic enrichment of virtual models are also discussed. Crowdsourced geodata can serve as a real alternative data source and VGI can be utilized for generating rich 3D city models.

Computer-guided laser probe for ablation of brain tumours with ultrashort laser pulses

A computer-guided laser probe has been developed for the application of ultrashort-pulsed lasers in neurosurgery. It is part of a novel operation concept for the treatment of deep-seated brain tumours. The system combines the positioning accuracy of stereotactic or neuronavigated instruments with the precise and therefore gentle characteristics of surgical lasers. The probe has an outer diameter of 5.5 mm and is directly inserted into the target volume. By a synchronized movement of three coaxial tubes, which guide the embedded optics, the laser radiation is focused at any time onto the current tissue surface. Since every single laser pulse has only a small effective volume of about 8 x 10(5) microm3, the application of a large number of succeeding pulses can be adapted to required geometries. Tissue fragments are removed from the growing operation cavity by continuous irrigation and suction through the laser probe. Blood vessels are detected by a confocal laser-scanning microscope, which is integrated into the probe, and can be closed by an additional coagulating laser. In this paper, the design and technical properties of the laser probe as well as its use in ablation and coagulation experiments are presented. A description of the overall operation system is given.

Towards Interactive 3D City Models on the Web

A ubiquitous accessibility of data over the Web nowadays is very common. Although the Web, 3D graphics, and geographic data are crossing their ways, common applications are typically based on technologies that are rather esoteric to most web-developers. Nevertheless, in the last couple of months, some efforts towards a seamless integration of 3D graphics into common Web browsers have been performed. Regarding the data of such applications, they are mostly proprietary and commercial data, which are collected by professional cartographers or surveyors. Nevertheless, following the Web 2.0 approach, within the last five years the trend of Volunteered Geographic Information (VGI) became popular, describing an ever expanding range of users who voluntarily and collaboratively collect geographic data. Trying to merge the mentioned trends and desires, within this paper the authors present a way to transform the crowdsourced OpenStreetMap data into a 3D city model. Contrary to other existing approaches towards OpenStreetMap 3D, they combine emerging and established Web technologies, allowing an easy consumption in arbitrary web browsers. The applied technologies are easy to learn and understand by the web community and allow for quick prototyping, and creating mash-ups with further spatially enabledWeb2.0 data.

Optical spectroscopy for stereotactic biopsy of brain tumors

Stereotactic biopsy procedure is performed to obtain a tissue sample for diagnosis purposes. Currently, a fiber-based mechano-optical device for stereotactic biopsies of brain tumors is developed. Two different fluorophores are employed to improve the safety and reliability of this procedure: The fluorescence of intravenously applied indocyanine green (ICG) facilitates the recognition of blood vessels and thus helps minimize the risk of cerebral hemorrhages. 5- aminolevulinic-acid-induced protoporphyrin IX (PpIX) fluorescence is used to localize vital tumor tissue. ICG fluorescence detection using a 2-fiber probe turned out to be an applicable method to recognize blood vessels about 1.5 mm ahead of the fiber tip during a brain tumor biopsy. Moreover, the suitability of two different PpIX excitation wavelengths regarding practical aspects was investigated: While PpIX excitation in the violet region (at 405 nm) allows for higher sensitivity, red excitation (at 633 nm) is noticeably superior with regard to blood layers obscuring the fluorescence signal. Contact measurements on brain simulating agar phantoms demonstrated that a typical blood coverage of the tumor reduces the PpIX signal to about 75% and nearly 0% for 633 nm and 405 nm excitation, respectively. As a result, 633 nm seems to be the wavelength of choice for PpIX-assisted detection of high-grade gliomas in stereotactic biopsy.

Fluorescence guidance during stereotactic biopsy

Objective: When a stereotactic biopsy is taken to enable histopathological diagnosis of a suspected brain tumor, it is essential to i) do this safely, that is not injure a major blood vessel and ii) to obtain relevant vital material from the tumor. We are investigating the suitability of Indocyanine Green (ICG) fluorescence for blood vessel recognition and 5- Aminolevulinic acid (5-ALA) induced Protoporphyrin IX (PpIX) fluorescence for identification of proliferative brain tumor tissue. Methods: A fiber-optic endoscopic approach was studied to generate and detect both fluorescence signals. PpIX concentrations in brain tumors have been measured by chemical extraction. Preliminary equipment was studied in a mouse model. Results: PpIX-concentrations in glioblastoma tissue showed high inner- and inter-patient variability, but each patient out of 15 with interpretable data showed at least one sample with a PpIX-concentration exceeding 2.4 μmol/l, which is easily detectable by state-of-the-art fiberoptic fluorescence spectroscopy and imaging. The imaging fluoroscope with 30,000 pixels resolution could be introduced through a position controlled stereotactic needle. ICG-fluorescence from vessels with diameters ≥ 0.1 mm can be detected with a contrast of 2-2.5 against surrounding tissue. Conclusion: Fluorescence detection during stereotactic biopsy might increase safety and precision of the procedure significantly.