Inviwo -- A Visualization System with Usage Abstraction Levels

The complexity of today's visualization applications demands specific visualization systems tailored for the development of these applications. Frequently, such systems utilize levels of abstraction to improve the application development process, for instance by providing a data flow network editor. Unfortunately, these abstractions result in several issues, which need to be circumvented through an abstraction-centered system design. Often, a high level of abstraction hides low level details, which makes it difficult to directly access the underlying computing platform, which would be important to achieve an optimal performance. Therefore, we propose a layer structure developed for modern and sustainable visualization systems allowing developers to interact with all contained abstraction levels. We refer to this interaction capabilities as usage abstraction levels, since we target application developers with various levels of experience. We formulate the requirements for such a system, derive the desired architecture, and present how the concepts have been exemplary realized within the Inviwo visualization system. Furthermore, we address several specific challenges that arise during the realization of such a layered architecture, such as communication between different computing platforms, performance centered encapsulation, as well as layer-independent development by supporting cross layer documentation and debugging capabilities

Visualització avançada de models mèdics

L'increment de la capacitat computacional de les targetes gràfiques i l'aparició de cascs de realitat virtual a preus relativament assequibles els darrers anys, ha permès el desenvolupament i la expansió de la exploració interactiva de models volumètrics en un entorn de realitat virtual immersiva. Aquest recurs, que actualment s'usa en diversos àmbits com la medicina o el disseny industrial, presenta certs problemes. Un dels més importants és com passar dels valors d'entrada del model a la representació gràfica que veiem i com podem modificar aquesta representació interactivament. Per fer aquesta traducció s'utilitza el que es coneix com a funció de transferència, que en la seva forma més bàsica relaciona el valor d'entrada a una opacitat i color. Aquest tipus de funcions de transferència, funcionen prou bé si es defineixen abans d'explorar el model però la seva modificació interactiva durant l'exploració és bastant incòmoda. L'objectiu d'aquest projecte consisteix en comprovar si l'ús d'una metàfora d'interacció usant style transfer function, un tipus de funcions de transferència que permeten una major abstracció de les dades i presenta un acabat similar a les imatges il·lustratives dels llibres mèdics, resulta més còmode i entenedor per l'usuari que una metàfora d'interacció usant una funció de transferència unidimensional.The increase in the computing capacity of graphics cards and the emergence of virtual reality headsets at relatively affordable prices in recent years has allowed the development and expansion of interactive exploration of volumetric models in an immersive virtual reality environment. Volume models, which are currently used in various fields such as medicine or industrial design, has certain problems. One of the most important is how to move from the input values of the model to the graphical representation that we see and how we can modify this representation interactively. For establishing this correspondence, what is known as a transfer function is used, which in its most basic way relates the input value to an opacity and a color. These types of transfer functions work well if they are defined before the user explores the model in real-time, but their interactive modification during exploration is quite cumbersome. The purpose of this project is to test if the use of an interaction metaphor using style transfer function, a type of transfer function that allows for greater abstraction of data and has a similar finishing than the illustrative images of medical books, is more comfortable and user-friendly than an interaction metaphor using a one-dimensional transfer function

The State of the Art of Spatial Interfaces for 3D Visualization

International audienceWe survey the state of the art of spatial interfaces for 3D visualization. Interaction techniques are crucial to data visualization processes and the visualization research community has been calling for more research on interaction for years. Yet, research papers focusing on interaction techniques, in particular for 3D visualization purposes, are not always published in visualization venues, sometimes making it challenging to synthesize the latest interaction and visualization results. We therefore introduce a taxonomy of interaction technique for 3D visualization. The taxonomy is organized along two axes: the primary source of input on the one hand and the visualization task they support on the other hand. Surveying the state of the art allows us to highlight specific challenges and missed opportunities for research in 3D visualization. In particular, we call for additional research in: (1) controlling 3D visualization widgets to help scientists better understand their data, (2) 3D interaction techniques for dissemination, which are under-explored yet show great promise for helping museum and science centers in their mission to share recent knowledge, and (3) developing new measures that move beyond traditional time and errors metrics for evaluating visualizations that include spatial interaction

Intuitive Exploration of Volumetric Data Using Dynamic Galleries

In this work we present a volume exploration method designed to be used by novice users and visitors to science centers and museums. The volumetric digitalization of artifacts in museums is of rapidly increasing interest as enhanced user experience through interactive data visualization can be achieved. This is, however, a challenging task since the vast majority of visitors are not familiar with the concepts commonly used in data exploration, such as mapping of visual properties from values in the data domain using transfer functions. Interacting in the data domain is an effective way to filter away undesired information but it is difficult to predict where the values lie in the spatial domain. In this work we make extensive use of dynamic previews instantly generated as the user explores the data domain. The previews allow the user to predict what effect changes in the data domain will have on the rendered image without being aware that visual parameters are set in the data domain. Each preview represents a subrange of the data domain where overview and details are given on demand through zooming and panning. The method has been designed with touch interfaces as the target platform for interaction. We provide a qualitative evaluation performed with visitors to a science center to show the utility of the approach.Funding Agencies|Swedish Research Council, VR [2011-5816]; Excellence Center at Linkoping and Lund in Information Technology (ELLIIT); Linnaeus Environment CADICS; Swedish e-Science Research Centre (SeRC)</p