Browsing by Author "Sundstedt, Veronica"

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    EUROGRAPHICS 2020: CGF 39-2 STARs Frontmatter
    (The Eurographics Association and John Wiley & Sons Ltd., 2020) Mantiuk, Rafal; Sundstedt, Veronica; Mantiuk, Rafal and Sundstedt, Veronica
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    Improving Ray Tracing Performance with Variable Rate Shading
    (The Eurographics Association, 2021) Dahlin, Alexander; Sundstedt, Veronica; Xu, Kai and Turner, Martin
    Hardware-accelerated ray tracing has enabled ray traced reflections for real-time applications such as games. However, the number of traced rays during each frame must be kept low to achieve expected frame rates. Therefore, techniques such as rendering the reflections at quarter resolution are used to limit the number of rays. The recent hardware features inline ray tracing, and variable rate shading (VRS) could be combined to limit the number of rays even further. This research aims to use hardware VRS to limit the number of rays while maintaining the visual quality in the final rendered image. An experiment with performance tests is performed on a rendering pipeline using different techniques to generate rays. The techniques use inline ray tracing combined with VRS and ray generation shaders. These are compared and evaluated using performance tests and the image evaluator FLIP. The results show that limiting the number of rays with hardware VRS leads to improved performance while the difference in visual quality remains comparable.
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    Possibilities and Challenges of Portraying Cultural Heritage Artefacts using Augmented Reality: the Mjällby Crucifix Case Study
    (The Eurographics Association, 2020) Garro, Valeria; Sundstedt, Veronica; Putta, Advaith; Sandahl, Christoffer; Spagnuolo, Michela and Melero, Francisco Javier
    The increasing application of immersive technologies, i.e. virtual reality (VR) and augmented reality (AR), in cultural heritage (CH) offers new ways of displaying artefacts and historical sites. VR and AR provide an added value to the visitor experience from several different aspects, e.g. interactivity or sense of presence. VR and AR technologies open the possibility for the visitor to visit reconstructions of historical sites and observe 3D replicas of CH artefacts. Moreover, these technologies, especially AR, can bring some artefacts back to their historical locations adding a new dimension to the visitor experience. We present an ongoing case study exploring the use of AR in the portrayal of a CH artefact, namely the Mjällby Crucifix in the Blekinge Museum, located in Southern Sweden. This crucifix is a medieval artefact which was originally placed in the Mjällby church and is currently preserved at the Blekinge Museum warehouse. The artefact is displayed lying in horizontal position on a low stage surrounded by other artefacts. Due to its large size (310 cm high and 260 cm wide) and its current position, it is not possible for the visitor to have a close view of the artefact. We plan to display a 3D replica of the artefact via an AR application using a hand-held device. The digital replica can be visualised in its original vertical position both in a chosen location in the museum and in the Mjällby church enhancing the visitor experience. A prototype of the AR application has been developed and showcased to a group of experts from the Blekinge Museum. The digitisation of the crucifix artefact has been done using an Artec Leo 3D scanner which captures both geometry and texture information. We developed a marker-based AR prototype application which runs on Android mobile devices supporting Google AR platform ARCore. We used a picture of the original crucifix as a marker image. The application detects this image which is supposed to lie on the floor or another horizontal surface, and displays the 3D model of the crucifix on top of it. An online questionnaire followed by a group interview with experts in the CH domain was conducted to discuss the AR prototype and the possibilities and challenges with the use of AR technology in digital CH. We focused on the context of Blekinge Museum exhibitions as an example of a regional museum. Four experts filled in the questionnaire and three of them participated in the group interview consisting of two stages. In the first part the experts were shown the AR prototype. This was followed by a group discussion mainly driven from the participants. In the second part the moderator presented additional considerations prepared in advance by the organisers by collecting personal reflections and information from background literature in the area of computer graphics applied to CH. The aim was to include a different perspective in the discussion and to gather insights about the potential differences and knowledge gaps between experts of different domains. Answers from the questionnaire and the group discussion highlighted established capability of AR technology such as exhibition enhancement and interaction, appealing to new target audiences and the possibility to display artefacts outside the museum: (i) expanding the geographic area of impact of the museum that aims at covering the regional territory, (ii) attracting visitors to the museum as sort of preview of the type of artefacts available on site. Regarding the challenges, much focus emerged on the cost of the technology, the necessity of building specific competence and expertise among the museum staff, and the usability and accessibility aspects of the AR applications. The Bring Your Own Device (BYOD) policy was mentioned as the ideal solution to tackle the problem of the costs of the devices which support also the usability since the visitors are more accustomed to handling their own devices. The BYOD policy implies the requirement of being available to the largest number of visitors, hence the AR application should be multiplatform and its availability should not be limited to the most recent and powerful mobile devices. Other mentioned challenges were the restricted computational resources of the devices and the necessity of applications maintenance (software updates). Aspects related to health and safety of sharing devices have also been discussed. The presented case study highlighted relevant aspects considered by the experts as well as providing new insights to take into account to make AR technology successful in virtual CH exhibitions of a regional museum. Future work will include improving the AR prototype adding interaction with the artefact, showcasing the AR prototype in the original location of the artefact to collect non-expert visitors expectations and run a usability study of the AR application. This work was supported in part by KK-stiftelsen Sweden, through the ViaTecH Synergy Project (contract 20170056).