Static Debugging of C Programs: Detection of Pointer Errors in Recursive Data Structures

The incorrect use of pointers is one of the most common source of bugs in imperative languages. In this context, any kind of static code checking capable of detecting potential bugs at compile time is welcome. This paper presents a static debugging technique for the detection of incorrect accesses to memory (dereferences of invalid pointers). The analysed language is a subset of C. The tool is based on a static analyser extended with assertions inserted in the body of the program. Assertions are of two kinds: static assertions automatically verified by the analyser, dynamic assertions treated as assumptions by the analyser. The technique deals with dynamically allocated data structures and it is accurate enough to handle circular structures

Sonic interaction with a virtual orchestra of factory machinery

This paper presents an immersive application where users receive sound and visual feedbacks on their interactions with a virtual environment. In this application, the users play the part of conductors of an orchestra of factory machines since each of their actions on interaction devices triggers a pair of visual and audio responses. Audio stimuli were spatialized around the listener. The application was exhibited during the 2013 Science and Music day and designed to be used in a large immersive system with head tracking, shutter glasses and a 10.2 loudspeaker configuration.Comment: Sonic Interaction for Virtual Environments, Minneapolis : United States (2014

Experiencing the past in virtual reality A virtual reality event for the French National Days of Archaeology

International audienceThis document reports a public exhibition organized during the French National Days of Archaeology, that is the result of an interdisciplinary collaboration between archaeologists and computer scientists, centered on the immersive virtual reality platform Immersia, a node of the European Visionair project. This public exhibition had three main goals: (i) presentating our interdisciplinary collaboration, (ii) communicating on the scientific results of this collaboration, and (iii) offering an immersive experience in the past for visitors. This paper presents the scientific context of the event, its organization, and a discussion on feedbacks

Preservative Approach to Study Encased Archaeological Artefacts

International audienceWe propose a workflow based on a combination of computed tomography, 3D images and 3D printing to analyse different archaeological material dating from the Iron Age, a weight axis, a helical piece, and a fibula. This workflow enables a preservative analysis of the artefacts that are unreachable because encased either in stone, corrosion or ashes. Computed tomography images together with 3D printing provide a rich toolbox for archaeologist work allowing to access a tangible representation of hidden artefacts. These technologies are combined in an efficient, affordable and accurate workflow compatible with Preventive archaeology constraints

Internal 3D Printing of Intricate Structures

International audienceAdditive technologies are increasingly used in Cultural Heritage process , for example in order to reproduce, complete, study or exhibit artefacts. 3D copies are based on digitization techniques such as laser scan or photogramme-try. In this case, the 3d copy remains limited to the external surface of objects. Medical images based digitization such as MRI or CT scan are also increasingly used in CH as they provide information on the internal structure of archaeological material. Different previous works illustrated the interest of combining 3D printing and CT scan in order to extract concealed artefacts from larger archaeological material. The method was based on 3D segmentation techniques within volume data obtained by CT scan to isolate nested objects. This approach was useful to perform a digital extraction, but in some case it is also interesting to observe the internal spatial organization of an intricate object in order to understand its production process. We propose a method for the representation of a complex internal structure based on a combination of CT scan and emerging 3D printing techniques mixing colored and transparent parts. This method was successfully applied to visualize the interior of a funeral urn and is currently applied on a set of tools agglomerated in a gangue of corrosion

Virtual reality tools for the West Digital Conservatory of Archaeological Heritage

International audienceIn the continuation of the 3D data production work made by the WDCAH, the use of virtual reality tools allows archaeologists to carry out analysis and understanding research about their sites. In this paper, we focus on the virtual reality services proposed to archaeologists in the WDCAH, through the example of two archaeological sites, the Temple de Mars in Corseul and the Cairn of Carn Island

From medical imaging to virtual reality for archaeology

The IRMA project aims to design innovative methodologies for research in the field of historical and archaeological heritage based on a combination of medical imaging technologies and interactive 3D restitution modalities (virtual reality, augmented reality, haptics, additive manufacturing). These tools are based on recent research results from a collaboration between IRISA, Inrap and the company Image ET and are intended for cultural heritage professionals such as museums, curators, restorers and archaeologists.Comment: in French languag

De l’imagerie médicale à la réalité virtuelle pour l’archéologie

International audienceThe IRMA project aims to design innovative methodologies for research in the field of historical and archaeological heritage based on a combination of medical imaging technologies and interactive 3D restitution modalities (virtual reality, augmented reality, haptics, additive manufacturing). These tools are based on recent research results from a collaboration between IRISA, Inrap and the company Image ET and are intended for cultural heritage professionals such as museums, curators, restorers and archaeologists

The West Digital Conservatory of Archaelogical Heritage Project

International audienceThe West Digital Conservatory of Archaeological Heritage project, a.k.a. WDCAH, is a new French research organization whose aim is to both ensure the preservation of digital archaeological data, and deliver expertise in production, analysis, visualization and virtual reality exploration techniques. This project is an interdisciplinary project composed of engineers and researchers in archaeology, computer science, virtual reality and 3D interaction with virtual environments. The major objectives of this conservatory project are: (i) sustainable and centralized safeguarding and archiving of 2D/3D data produced by the archaeological community; (ii) free access to metadata; (iii) secure access to data for the different actors involved in scientific projects and (iv) the support and advice for these actors in the 3D data production and exploration through the latest digital technologies, modeling tools and virtual reality systems. Today the first activities of the WDCAH mainly concern digital models production using photogrammetry, 3D laser scans, and 3D computer graphics software. We are currently working on the reconstitution of six archaeological sites located in the west of France ranging from prehistory to the Middle Ages: the Cairn of Carn Island, the covered pathway of Roh Coh Coet, the Goh Min Ru megalithic site, the gallo-roman mansion of Vanesia, the keep of the Château de Sainte-Suzanne, the Porte des Champs of the Château d'Angers. Other proposals are currently under study

Audio-Visual Attractors for Capturing Attention to the Screens When Walking in CAVE Systems

International audienceIn four-sided CAVE-like VR systems, the absence of the rear wall has been shown to decrease the level of immersion and can introduce breaks in presence. In this paper it is investigated to which extent user's attention can be driven by visual and auditory stimuli in a four-sided CAVE-like system. An experiment was conducted in order to analyze how user attention is diverted while physically walking in a virtual environment, when audio and/or visual attractors are present. The foursided CAVE used in the experiment allowed to walk up to 9m in straight line. An additional key feature in the experiment is the fact that auditory feedback was delivered through binaural audio rendering techniques via non-personalized head related transfer functions (HRTFs). The audio rendering was dependent on the user's head position and orientation, enabling localized sound rendering. The experiment analyzed how different "attractors" (audio and/or visual, static or dynamic) modify the user's attention. The results of the conducted experiment show that audio-visual attractors are the most efficient attractors in order to keep the user's attention toward the inside of the CAVE. The knowledge gathered in the experiment can provide guidelines to the design of virtual attractors in order to keep the attention of the user and avoid the "missing wall". Index Terms: Audi