Marcel Lancelle - Publications

The invention pertains to a method for transferring properties from a reference dental model (20) to a primary dental model (10), wherein the method comprises a non-rigid alignment of the primary dental model and the reference dental model, comprising applying an algorithm to minimize a measure of shape deviation between the primary dental model and the reference dental model, and transferring properties of the reference dental model to the primary dental model.

The invention pertains to a method for realistic visualization of a 3D virtual dental model (1) in a 2D image (20) of a face, the method comprising estimating or assuming a lighting situation in the image of the face, determining boundaries of an inner mouth region in the image, computing, based on the boundaries of the inner mouth region, on a 3D face geometry and on the lighting situation, a shadowing in the inner mouth region, computing a lighting of the dental model (1) based at least on the computed shadowing, and visualizing the dental model (1) and the 2D image (20), wherein at least the inner mouth region in the image is overlaid with a visualization (21) of the dental model having the computed lighting.

The present invention pertains to a computer-implemented method for visualization of virtual three-dimensional models of dentitions in an image or image stream of a person's face. In particular, the described method allows realistic, i.e. naturally looking, visualization of dental models in dental virtual mock-up applications, such as dental augmented reality applications..

The present invention relates to a computer implemented method for visualizing two-dimensional images obtained from a three-dimensional model of a dental situation in each image of the face of a patient recorded by a camera in a video sequence of subsequent images, each image including the mouth opening of the patient, wherein the three-dimensional model of dental situation is based on a three-dimensional model of the dentition of the patient and compared to the three-dimensional model of the dentition includes modifications due to dental treatment or any other dental modification.

The invention pertains to a method for exporting design data of a virtual 3D dental design model (12) from an AR application, the AR application being adapted to visualize the dental design model with a preliminary pose and scale (13) in an image (11) of a face comprising a mouth region with a dental situation. The invention further pertains to a method for visualizing a 3D dental design model in an AR application.

The invention pertains to a method for transferring properties from a reference dental model (20) to a primary dental model (10), wherein the method comprises a non-rigid alignment of the primary dental model and the reference dental model, comprising applying an algorithm to minimize a measure of shape deviation between the primary dental model and the reference dental model, and transferring properties of the reference dental model to the primary dental model.

The present invention relates to a computer implemented method for modifying a digital three-dimensional model (3) of a dentition comprising:

• displaying an image of the dentition by applying a virtual camera to the three-dimensional model to render the image for a display (1);
• acquiring a line drawn by a user on the image on the display (1);
• projecting the acquired line, using the virtual camera (4), to a three-dimensional projection surface (7) approximating the shape of the dental arches and extending the upper and lower dental arches to cover any opening therebetween;
• obtaining visible teeth arch contour curves, namely incisal curve and gingiva border curve, of the upper and lower teeth arches, and projecting the teeth arch contour curves to the projection surface;
• selecting one of the teeth arch contour curves as teeth arch contour curve to be modified and selecting the other teeth arch contour curve of the same teeth arch or a curve derived therefrom as a baseline curve;
• deforming all teeth belonging to the selected contour curve to be modified along the projected line in the three-dimensional model of the dentition in a length direction such that at least parts of the selected contour curve to be modified, after deformation and projection to the projection surface, coincide with the projected line and any remaining parts of the selected contour curve to be modified are located between the projected line and the baseline curve, whereas the baseline curve remains unaffected by the deformation.

In a photo, motion blur can be used as an artistic style to convey motion and to direct attention. In panning or tracking shots, a moving object of interest is followed by the camera during a relatively long exposure. The goal is to get a blurred background while keeping the object sharp. Unfortunately, it can be difficult to impossible to precisely follow the object. Often, many attempts or specialized physical setups are needed.
This paper presents a novel approach to create such images. For capturing, the user is only required to take a casually recorded hand-held video that roughly follows the object. Our algorithm then produces a single image which simulates a stabilized long time exposure. This is achieved by first warping all frames such that the object of interest is aligned to a reference frame. Then, optical flow based frame interpolation is used to reduce ghosting artifacts from temporal undersampling. Finally, the frames are averaged to create the result.
As our method avoids segmentation and requires little to no user interaction, even challenging sequences can be processed successfully. In addition, artistic control is available in a number of ways. The effect can also be applied to create videos with an exaggerated motion blur. Results are compared with previous methods and ground truth simulations. The effectiveness of our method is demonstrated by applying it to hundreds of datasets. The most interesting results are shown in the paper and in the supplemental material.

STATEMENT OF PROBLEM: Three-dimensional visualization for pretreatment diagnostics and treatment planning is necessary for surgical and prosthetic rehabilitations. The reliability of a novel 3D facial camera is unclear.
PURPOSE: The purpose of this clinical study was to evaluate the reliability of a novel medical facial camera system in capturing the 3D geometry of the face in a single exposure.
MATERIAL AND METHODS: Completely edentulous participants (n=12: women=7, men=5; mean age: 74.6 years) were included in this pilot study. Images were captured with and without the prostheses in situ while maintaining "serious" and "full-smile" facial expressions. Images were captured using a mobile and a static system. The working times for the participant installation and image captures were recorded. Operator and participant perceptions of the entire experience were recorded by using visual analog scale questionnaires. Nonparametric tests were used for statistical analyses (a=.05).
RESULTS: The mean ±standard deviation difference between the clinical and digital measurements was 1.95 ±0.33 mm. Intraclass correlation coefficients computed for the 2 examiners against clinical measurements were all above 0.5. The interexaminer reliability coefficient of digital measurement was above 0.909.
CONCLUSIONS: The 3D facial geometry obtained from the novel medical facial camera system was found to be reliable and clinically acceptable. Inconsistencies in measurements for a few specific facial landmarks may arise, but these can be avoided by thorough examiner calibration before undertaking the digital measurements.

STATEMENT OF PROBLEM: An evaluation of user satisfaction and image quality of a novel handheld purpose-built mobile camera system for 3-dimensional (3D) facial acquisition is lacking.
PURPOSE: The purpose of this pilot clinical study was to assess and compare the effectiveness between a handheld mobile camera system designed for facial acquisition and a fixed static camera arrangement by comparing the time effectiveness and the operator and participant preference for the 2 techniques of image capture.
MATERIAL AND METHODS: Completely edentulous participants (n=12: women=7, men=5; mean age: 74.6 years) were included in this pilot study. Images were captured with and without the prostheses in situ while maintaining "serious" and "full-smile" facial expressions. Images were captured using a mobile and a static system. The working times for the participant installation and image captures were recorded. Operator and participant perceptions of the entire experience were recorded by using visual analog scale questionnaires. Nonparametric tests were used for statistical analyses (a=.05).
RESULTS: The installation time was significantly shorter for the mobile system (static=24 ±13 seconds; mobile=10 ±10 seconds), but the differences in the image capture times were not statistically significant (static: 29 ±5 seconds; mobile: 40 ±18 seconds). Operator preference was in favor of the mobile system with regard to working time (P=.002), difficulty in using (installation: P=.002; handling: P=.045), and camera weight (P=.002); however, they preferred the static arrangement for image quality (P=.003) and comfort (P=.013). The participants rated the entire photographic experience favorably, and 10 of 12 participants preferred the static camera over the mobile one.
CONCLUSIONS: Despite the complexity of the installation, the static system was evaluated better for image quality; the mobile system was easier in installation and handling. The operators preferred the mobile system, and the participants preferred the static system.

Light painting is an artform where a light source is moved during a long-exposure shot, creating trails resembling a stroke on a canvas. It is very difficult to perform because the light source needs to be moved at the intended speed and along a precise trajectory. Additionally, images can be corrupted by the person moving the light. We propose computational light painting, which avoids such artifacts and is easy to use. Taking a video of the moving light as input, a virtual exposure allows us to draw the intended light positions in a post-process. We support animation, as well as 3D light sculpting, with high-quality results.

Digital technologies have the potential to disrupt many traditional industries including dentistry. Software becomes the main communication technology and a useful tool for showing patients the possibilities for enhancing their smiles. Despite the need for processing the visual content, today’s solutions do not correspond to the state of the art in computer vision.
We demonstrate a mobile application that enables users to virtually try on new teeth and dental restorations in real time. Based on our proprietary visual computing technology stack built on machine learning and dento-facial analytics, we create realistic previews for patients, dental professionals, and the dental industry.

In this paper we present a method to model and simulate a lens such that its caustic reveals a stereoscopic 3D image when viewed through anaglyph glasses. By interpreting lens dispersion as stereoscopic disparity, our method optimizes the shape and arrangement of prisms constituting the lens, such that the resulting anaglyph caustic corresponds to a given input image defined by intensities and disparities. In addition, a slight change of the lens distance to the screen causes a 3D parallax effect that can also be perceived without glasses. Our proposed relaxation method carefully balances the resulting pixel intensity and disparity error, while taking the subsequent physical fabrication process into account. We demonstrate our method on a representative set of input images and evaluate the anaglyph caustics using multi-spectral photon tracing. We further show the fabrication of prototype lenses with a laser cutter as a proof of concept.

We investigate the influence of motion effects in the domain of mobile Augmented Reality (AR) games on user experience and task performance. The work focuses on evaluating responses to a selection of synthesized camera oriented reality mixing techniques for AR, such as motion blur, defocus blur, latency and lighting responsiveness. In our cross section of experiments, we observe that these measures have a significant impact on perceived realism, where aesthetic quality is valued. However, lower latency records the strongest correlation with improved subjective enjoyment, satisfaction, and realism, and objective scoring performance. We conclude that the reality mixing techniques employed are not significant in the overall user experience of a mobile AR game, except where harmonious or convincing blended AR image quality is consciously desired by the participants.

We explore a location-based game concept that encourages real-world interactions and gamifies daily commuting activities. Enhanced with augmented reality technology, we create an immersive, pervasive trading game called Gnome Trader, where the player engages with the game by physically traveling to predefined locations in the city and trading resources with virtual gnomes. As the virtual market is a crucial component of the game, we take special care to analyze various economic game mechanics. We explore the parameter space of different economic models using a simulation of the virtual economy. We evaluate the overall gameplay as well as the technical functionality through several play tests.

We investigate the influence of motion effects in the domain of mobile Augmented Reality (AR) games on user experience and task performance. The work focuses on evaluating responses to a selection of synthesized camera oriented reality mixing techniques for AR, such as motion blur, defocus blur, latency and lighting responsiveness. In our cross section of experiments, we observe that these measures have a significant impact on perceived realism, where aesthetic quality is valued. However, lower latency records the strongest correlation with improved subjective enjoyment, satisfaction, and realism, and objective scoring performance. We conclude that the reality mixing techniques employed are not significant in the overall user experience of a mobile AR game, except where harmonious or convincing blended AR image quality is consciously desired by the participants.

Jumping photos are very popular, particularly in the contexts of holidays, social events and entertainment. However, triggering the camera at the right time to take a visually appealing jumping photo is quite difficult in practice, especially for casual photographers or self-portraits. We propose a fully automatic method that solves this practical problem. By analyzing the ongoing jump motion online at a fast rate, our method predicts the time at which the jumping person will reach the highest point and takes trigger delays into account to compute when the camera has to be triggered. Since smartphones are more and more popular, we focus on these devices which leads to some challenges such as limited computational power and data transfer rates. We developed an Android app for smartphones and used it to conduct experiments confirming the validity of our approach.

We give an overview on the integrated, modular toolset and basic building blocks available to achieve interactive 3D experiences on the web in the context of augmented-reality and mixed-reality applications.

We describe a multi-modal brain-computer interface (BCI) experiment, situated in a highly immersive CAVE. A subject sitting in the virtual environment controls the main character of a virtual reality game: a penguin that slides down a snowy mountain slope. While the subject can trigger a jump action via the BCI, additional steering with a game controller as a secondary task was tested. Our experiment profits from the game as an attractive task where the subject is motivated to get a higher score with a better BCI performance. A BCI based on the so-called brain-switch was applied, which allows discrete asynchronous actions. Fourteen subjects participated, of which 50% achieved the required performance to test the penguin game. Comparing the BCI performance during the training and the game showed that a transfer of skills is possible, in spite of the changes in visual complexity and task demand. Finally and most importantly, our results showed that the use of a secondary motor task, in our case the joystick control, did not deteriorate the BCI performance during the game. Through these findings, we conclude that our chosen approach is a suitable multi-modal or hybrid BCI implementation, in which the user can even perform other tasks in parallel.

Single-chip color DLP projectors show the red, green and blue components one after another. When the gaze moves relative to the displayed pixels, color fringes are perceived. In order to reduce these artefacts, many devices show the same input image twice at the double rate, i.e. a 60Hz source image is displayed with 120Hz. Consumer stereo projectors usually work with time interlaced stereo, allowing to address each of these two images individually. We use this so called 3D mode for mono image display of fast moving objects. Additionally, we generate a separate image for each individual color, taking the display time offset of each color component into account. With these 360 images per second we can strongly reduce ghosting, color fringes and jitter artefacts on fast moving objects tracked by the eye, resulting in sharp objects with smooth motion.
Real-time image generation at such a high frame rate can only be achieved for simple scenes or may only be possible by severely reducing quality. We show how to modify a motion blur post processing shader to render only 60frames/second and efficiently generate good approximations of the missing frames.

While navigation systems for cars are in widespread use, only recently, indoor navigation systems based on smartphone apps became technically feasible. Hence tools in order to plan and evaluate particular designs of information provision are needed. Since tests in real infrastructures are costly and environmental conditions cannot be held constant, one must resort to virtual infrastructures. In this paper we present a hands-free navigation in such virtual worlds using the Microsoft Kinect in our four-sided Definitely Affordable Virtual Environment (DAVE). We designed and implemented navigation controls using the user's gestures and postures as the input to the controls. The installation of expensive and bulky hardware like treadmills is avoided while still giving the user a good impression of the distance she has travelled in virtual space. An advantage in comparison to approaches using head mounted augmented reality is that the DAVE allows the users to interact with their smartphone. Thus the effects of different indoor navigation systems can be evaluated already in the planning phase using the resulting system.

This thesis covers research on new and alternative ways of interaction with computers. Virtual Reality and multi touch setups are discussed with a focus on three dimensional rendering and photographic applications in the field of Computer Graphics. Virtual Reality (VR) and Virtual Environments (VE) were once thought to be the future interface to computers. However, a lot of problems prevent an everyday use. This work shows solutions to some of the problems and discusses remaining issues.
Hardware for Virtual Reality is diverse and many new devices are still being developed. An overview on historic and current devices and VE setups is given and our setups are described. The DAVE, an immersive projection room, and the HEyeWall Graz, a large high resolution display with multi touch input are presented. Available processing power and in some parts rapidly decreasing prices lead to a continuous change of the best choice of hardware. A major influence of this choice is the application. VR and multi touch setups often require sensing or tracking the user, optical tracking being a common choice. Hardware and software of an optical 3D marker tracking and an optical multi touch system are explained.
The Davelib, a software framework for rendering 3D models in Virtual Environments is presented. It allows to easily port existing 3D applications to immersive setups with stereoscopic rendering and head tracking. Display calibration and rendering issues that are special to VR setups are explained. User interfaces for navigation and manipulation are described, focusing on interaction techniques for the DAVE and for multi touch screens. Intuitive methods are shown that are easy to learn and use, even for computer illiterates. Exemplary applications demonstrate the potential of immersive and non-immersive setups, showing which applications can most benefit from Virtual Environments. Also, some image processing applications in the area of computational photography are explained, that help to better depict the captured scene.

Today’s super zoom cameras offer a large optical zoom range of over 30x. It is easy to take a wide angle photograph of the scene together with a few zoomed in high resolution crops. Only little work has been done to appropriately display the high resolution photo as an inset. Usually, to hide the resolution transition, alpha blending is used. Visible transition boundaries or ghosting artifacts may result. In this paper we introduce a different, novel approach to overcome these problems. Across the transition, we gradually attenuate the maximum image frequency. We achieve this with a Gaussian blur with an exponentially increasing standard deviation.

We address artifacts at corners in soft edge blend masks for tiled projector arrays. We compare existing and novel modifications of the commonly used weighting function and analyze the first order discontinuities of the resulting blend masks. In practice, e.g. when the projector lamps are not equally bright or with rear projection screens, these discontinuities may lead to visible artifacts. By using first order continuous weighting functions, we achieve significantly smoother results compared to commonly used blend masks.

Existing visual surveillance systems typically require that human operators observe video streams from different cameras, which becomes infeasible if the number of observed cameras is ever increasing. In this paper, we present a new surveillance system that combines automatic video analysis (i.e., single person tracking and crowd analysis) and interactive visualization. Our novel visualization takes advantage of a high resolution display and given 3D information to focus the operator’s attention to interesting/critical areas of the observed area. This is realized by embedding the results of automatic scene analysis techniques into the visualization. By providing different visualization modes, the user can easily switch between the different modes and can select the mode which provides most information. The system is demonstrated for a real setup on a university campus.

Camera-based object detection and tracking are image processing tasks that typically do not take 3D information into account. Spatial relations, however, are sometimes crucial to judge the correctness or importance of detection and tracking results. Especially in applications with a large number of image processing tasks running in parallel, traditional methods of presenting detection results do not scale. In such cases it can be very useful to transform the detection results back into their common 3D space. We present a computer graphics system that is capable of showing a large number of detection results in real-time, using different levels of abstraction, on various hardware configurations. As example application we demonstrate our system with a surveillance task involving eight cameras.

The DAVE is an immersive projection environment, a foursided CAVE. DAVE stands for ’definitely affordable virtual environment’. ’Affordable’ means that by mostly using standard hardware components we can greatly reduce costs compared to other commercial systems. We show the hardware setup and some applications in the accompaning video. In 2005 we buildt a new version of our DAVE at the University of Technology in Graz, Austria. Room restrictions motivated a new compact design to optimally use the available space. The back projection material with a custom shape is streched to the wooden frame to provide a flat surface without ripples.

We present several novel ways of interaction and navigation in virtual worlds. Using the optical tracking system of our four-sided Definitely Affordable Virtual Environment (DAVE), we designed and implemented navigation and movement controls using the user’s gestures and postures. Our techniques are more natural and intuitive than a standard 3D joystick-based approach, which compromises the immersion’s impact.

We describe first steps towards a suite of tools for CH professionals to set up and run digital exhibitions of cultural 3D artifacts in museums. Both the authoring and the presentation views shall finally be as easy to use as, e.g., Microsoft Powerpoint. But instead of separated slides our tool uses pre-defined 3D scenes, called "layouts", containing geometric objects acting as placeholders, called "drop targets". They can be replaced quite easily, in a drag-and-drop fashion, by digitized 3D models, and also by text and images, to customize and adapt a digital exhibition to the style of the real museum. Furthermore, the tool set contains easy-to-use tools for the rapid 3D modeling of simple geometry and for the alignment of given models to a common coordinate system.
The technical innovation is that the tool set is not a monolithic application. Instead it is completely based on scripted designs, using the OpenSG scene graph engine and the GML scripting language. This makes it extremely flexible: Anybody capable of drag-and-drop can design 3D exhibitions. Anybody capable of GML scripting can create new designs. And finally, we claim that the presentation setup of our designs is 'grandparent-compliant', meaning that it permits to the public audience the detailed inspection of beautiful cultural 3D objects without getting lost or feeling uncomfortable.

Addressing the typically time consuming adjustment of projector equipment in VR installations we propose an easy to implement projector calibration method that effectively corrects images projected onto planar surfaces and which does not require any additional hardware. For hardware accelerated 3D applications only the projection matrix has to be modified slightly thus there is no performance impact and existing applications can be adopted easily.

Leapfrog 3D is 3D visualization software for geological modeling focusing on the mining domain. The tool allows users to filter, analyze and visualize different types of underground measurements (drill hole, seismic data, etc.). The software provides a much faster way of generating possible raw grade morphological models compared to the long explicit modeling sessions needed with current classical tools. By using implicit modeling and a proprietary interpolating algorithm (fastRBF^TM), geologists can simply introduce an interpreted morpholocical model, and the software will converge rapidly to a new meshing solution (Figure 1).
This report is a response to the company request to explore new interface tools that can assist with product presentation and also provide easy navigation with a better depth perception. Moreover, the company is also interested in exploring the possibilities of a Post-WIMP¹ Interface. We present in this document requirements identified during our observations and discussions, following by a review of current state of the art interface techniques (section 3) and a selected of possible solution ideas (section 4).

Many different projects exist that are more or less related to large public interactive displays. Most of them exist for research purposes. The following text describes different issues, ideas and existing solutions.

This research covers issues of automatic generation and visualization of a 3D city model using existing digital data. Air photos, LIDAR point clouds and soil usage and cadastral maps are used as data sources for the automated data fusion in a sample implementation. Combining existing techniques and new ideas, the developed framework enables automatic information enrichment and generation of plausible details.
Data conversion, model generation and real time visualization are achieved using a standard PC for the whole area of 200km². Real world data was used including all the practical problems involved.

Das Thema der 3D-Stadtmodelle ist sehr vielfältig und interdisziplinär. Dieses Kapitel gibt einen Überblick über den behandelten Stoff und die Ziele dieser Diplomarbeit.
Neben theoretischen Überlegungen sollte auch die konkrete Realisierung einzelner Aspekte unter den gegebenen Einschränkungen erfolgen. Ein schnelles Ergebnis ohne zusätzliche Kosten erforderte die automatische Verarbeitung verfügbarer bereits vorhandener digitaler Daten. Dadurch wurde es auch möglich, die Daten für eine ganze Stadt zu verarbeiten. Mit Hilfe der Implementierung können Forschung und Praxis verknüpft werden und zahlreiche weitere Forschungsprojekte bieten sich an, die auf dieser Grundlage aufbauen können. Es stand kein Komplett-System zur Verfügung, auf das aufgebaut werden konnte, so dass von Grund auf neu angefangen und vieles neu implementiert werden musste. Dadurch hielten sich zwar die Einschränkungen der externen Komponenten in Grenzen, doch war nur Zeit für einfache Realisierungen; es gibt für alle Teilbereiche der Erzeugung und Visualisierung bereits jeweils bessere Implementierungen. Der entstandene "CityModelViewer" ist dennoch bereits ein nützliches Tool, das diverse Arten von Daten aus ganz unterschiedlichen Quellen nutzen und bereits auf einem durchschnittlich ausgestatteten PC interaktiv visualisieren kann.
Mit Hilfe von Daten der Stadt Braunschweig wurden nach und nach immer mehr Programmteile entwickelt. So wurden hauptsächlich die für diese Stadt relevanten Probleme behandelt. Die konkrete Bearbeitung von Problemen ist ohne vorhandene realistische Daten kaum sinnvoll und wurde daher wenig berücksichtigt. Für Braunschweig existierte noch gar kein digitales 3D-Stadtmodell, so dass dies eine gute Untersuchung für später geplante professionelle Projekte darstellt. So können auch die Mitarbeiter der Stadt schon jetzt erste praktische Erfahrungen auf diesem Gebiet sammeln. Eine Nutzung außerhalb der genannten Bereiche, z.B. im privaten Umfeld, ist leider aus rechtlichen Gründen wegen der benutzten Daten nur sehr eingeschränkt möglich.

Die Erstellung von 3D Modellen ist ein wichtiger Schritt in der Computergraphik. Mit heutigen Modellierungswerkzeugen ist dies für manche Objekte einfach zu erfüllen, doch gibt es auch viele Objekte, bei denen eine Modellierung sehr aufwendig wäre. 3D-Scanner helfen hier weiter, sofern das Objekt schon existiert und verfügbar ist. Bei jedem der vielen Verfahren des 3D Scannens gibt es Einschränkungen bezüglich der Größe, Form, Konsistenz oder anderen Materialeigenschaften des Objektes. Doch das 3D-Scannen wird häufig einfach aus finanziellen Gründen nicht eingesetzt.
Das Ziel dieser Studienarbeit war die Konstruktion einer einfachen und preisgünstigen Hardware sowie die Erstellung der Software. Das Verfahren "shape from silhouette" sollte benutzt und für automatisierte Aufnahmen ein Drehteller konstruiert werden. Dabei wird das Objekt aus verschiedenen Blickwinkeln vor einem einfarbigen Hintergrund fotografiert und die Anteile jedes Fotos außerhalb des Objektes aus einem soliden Block ausgestanzt. Dadurch wird allerdings nur die konvexe Hülle des Objekts rekonstruiert, was der größte Nachteil dieses Ansatzes ist.
Für die automatische Segmentierung der Bilder darf das Objekt auch keine Farben ähnlich der Hintergrundfarbe enthalten bzw. diese stark reflektieren oder transparent durchscheinend sein.
Ein Vorteil ist die Möglichkeit der manuellen Korrektur der Segmentierung, was prinzipiell das Scannen von Objekten mit beliebiger Oberfläche erlaubt. Ebenfalls vorteilhaft sind die geringen Hardwarekosten. Mit einiger manueller Arbeit ist sogar eine grobe Rekonstruktion eines Objekts mit Hilfe von normalen, unkalibrierten Fotos möglich.