Portuguese Meeting on Computer Graphics and Interaction 2015
Permanent URI for this collection
Browse
Browsing Portuguese Meeting on Computer Graphics and Interaction 2015 by Author "Jorge, Joaquim"
Now showing 1 - 2 of 2
Results Per Page
Sort Options
Item Design de Funções Transferência para Imagens Médicas 3D recorrendo a uma Interface baseada em Esboços(The Eurographics Association, 2020) Parreira, Pedro F.; Mendes, Ana R.; Lopes, Daniel Simões; Jorge, Joaquim; Dias, Paulo and Menezes, PauloThe visual quality of volume rendering images and the contrast between different anatomical structures strongly depends on the type of transfer function that is applied by the volume renderer. While conventional windowicon-menu-pointer approaches refer the user to apply pre-defined transfer functions for isolating specific tissues, these are not always desirable for many clinical and surgical scenarios. This leaves the user with the tedious and time consuming task of manual transfer function design. In order to make this task more natural, we propose a sketch-based interface where touch gestures are used to directly control voxel opacity and colour. We also present new transfer function design approaches that aim to reduce the number of trial and error iterations, which usually are necessary for finding appropriate transfer functions. By following our approach, users were able to more rapidly explore and understand volume data, as the number iterations necessary to obtain a desirable transfer function where reduced. For both transfer function design and volume manipulation tasks users responded more favourably to our sketch-based interface when compared to standard mouse and keyboard controls, as the former approach promotes reduced design iterations and improve the user's overall understanding of the data.Item Mid-Air Manipulation of 3D Models in (Semi-) Immersive Virtual Environments(The Eurographics Association, 2020) Rodrigues, Vasco; Mendes, Daniel; Ferreira, Alfredo; Jorge, Joaquim; Dias, Paulo and Menezes, PauloIf the interactions made on multi-touch surfaces can be moved to the air above them, a user will have access to a powerful tool. The possibility of tracking the hands' movement in mid-air, creates a world full of interaction possibilities. Despite having been created consolidated solutions for multi-touch interactions, these are limited to a bi-dimensional space, preventing the possibility of direct interactions on the visualization space. Some works were created to try and overcome this problem, however most of them use intrusive techniques, don't use stereoscopy or virtual reality or are lacking accuracy. This work had the objective to explore and evaluate which techniques allow to manipulate with precision 3D objects in mid-air, on a non intrusive semi-immersive/immersive environment. With this work it was possible to observe that the mid-air interactions in immersive systems are the most efficient and satisfying method for users, due to the direct manipulation of 6 degrees of freedom, which mimics the way with which we interact with physical objects.