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Publications

Publications by Miguel Correia Melo

2019

Adaptation and Validation of the Temple Presence Inventory in a Portuguese Population

Authors
Vasconcelos Raposo, J; Bessa, M; Teixeira, CM; Cabral, L; Melo, M;

Publication
INTERNATIONAL JOURNAL OF HUMAN-COMPUTER INTERACTION

Abstract
The present study aims to translate and validate the Temple Presence Inventory (TPI) for the Portuguese context, respecting the maintenance of an equivalent semantics as well as the validity of its contents and concepts. This study also aims to verify the psychometric properties of the instrument (factor validity and internal consistency). The sample consisted of 455 individuals (male = 271, female = 184). The fidelity of the factors varied between 0.5 and 0.84. The confirmatory factor analysis produced a theoretical model with 38 items distributed among eight factors. The covariance between some residual errors of instrument items was considered, and the following fit indices were observed: chi 2/df = 2.073; GFI = 0.858; CFI = 0.887; RSMEA = 0.049; AIC = 1527. The results confirm the appropriateness of the version adapted to the Portuguese language of the TPI and that it can be used in research projects aiming to evaluate Presence in the Portuguese-speaking population (Europe).

2018

Tone Mapping HDR Panoramas for Viewing in Head Mounted Displays

Authors
Melo, M; Bouatouch, K; Bessa, M; Coelho, H; Cozot, R; Chalmers, A;

Publication
Proceedings of the 13th International Joint Conference on Computer Vision, Imaging and Computer Graphics Theory and Applications (VISIGRAPP 2018) - Volume 1: GRAPP, Funchal, Madeira, Portugal, January 27-29, 2018.

Abstract
Head-mounted displays enable a user to view a complete environment as if he/she was there; providing an immersive experience. However, the lighting in a full environment can vary significantly. Panoramic images captured with conventional, Low Dynamic Range (LDR), imaging of scenes with a large range of lighting conditions, can include areas of under- or over-exposed pixels. High Dynamic Range (HDR) imaging, on the other hand, is able to capture the full range of detail in a scene. However, HMDs are not currently HDR and thus the HDR panorama needs to be tone mapped before it can be displayed on the LDR HMD. While a large number of tone mapping operators have been proposed in the last 25 years, these were not designed for panoramic images, or for use with HMDs. This paper undertakes a two part subjective study to investigate which of the current, state-of-the-art tone mappers is most suitable for use with HMDs.

2015

Evaluation of Tone-Mapping Operators for HDR Video Under Different Ambient Luminance Levels

Authors
Melo, M; Bessa, M; Debattista, K; Chalmers, A;

Publication
COMPUTER GRAPHICS FORUM

Abstract
Since high dynamic range (HDR) displays are not yet widely available, there is still a need to perform a dynamic range reduction of HDR content to reproduce it properly on standard dynamic range (SDR) displays. The most common techniques for performing this reduction are termed tone-mapping operators (TMOs). Although mobile devices are becoming widespread, methods for displaying HDR content on these SDR screens are still very much in their infancy. While several studies have been conducted to evaluate TMOs, few have been done with a goal of testing small screen displays (SSDs), common on mobile devices. This paper presents an evaluation of six state-of-the-art HDR video TMOs. The experiments considered three different levels of ambient luminance under which 180 participants were asked to rank the TMOs for seven tone-mapped HDR video sequences. A comparison was conducted between tone-mapped HDR video footage shown on an SSD and on a large screen SDR display using an HDR display as reference. The results show that there are differences between the performance of the TMOs under different ambient lighting levels and the TMOs that perform well on traditional large screen displays also perform well on SSDs at the same given luminance level.

2016

HDR video on small screen devices

Authors
Melo, M; Bessa, M; Debattista, K; Chalmers, A;

Publication
High Dynamic Range Video: Concepts, Technologies and Applications

Abstract
Mobile devices are now widespread and multimedia consumption on these devices has increased significantly in recent years. More and more high dynamic range (HDR) content is being produced and its imminent adoption by the broadcast community means that there will soon be a demand to visualize HDR content on mobile devices. Mobile devices, however, have certain differences compared to traditional viewing devices. In particular, they are usually used on-the-go, making the context variables such as ambient lighting levels, or reflections important variables that need to be considered. Furthermore, despite their evolution so far, mobile devices usually have additional hardware limitations such as power supply, display features, or local storage availability. This chapter provides an overview of the work that has been conducted so far in addressing HDR video for mobile devices in order to ensure an optimal experience.

2018

Immersive Edition of Multisensory 360 Videos

Authors
Coelho, H; Melo, M; Barbosa, L; Martins, J; Teixeira, MS; Bessa, M;

Publication
Trends and Advances in Information Systems and Technologies - Volume 2 [WorldCIST'18, Naples, Italy, March 27-29, 2018]

Abstract
The current technologic proliferation has originated new paradigms concerning the production and consumption of multimedia content. This paper proposes a multisensory 360 video editor that allows producers to edit such contents with high levels of customization. This authoring tool allows the edition and visualization of 360 video with the novelty of allowing to complement the 360 video with multiple stimuli such as audio, haptics, and olfactory. In addition to this multisensory feature, the authoring tool allows customizing individually each of the stimuli to provide an optimal multisensory user experience. A usability evaluation has revealed the pertinence of the editor, where it was verified an effectiveness rate of 100%, only one help request out of 10 participants, and positive efficiency. Satisfaction-wise, results equally revealed high level of satisfaction as the average score was 8.3 out of 10. © Springer International Publishing AG, part of Springer Nature 2018.

2017

A multisensory virtual experience model for thematic tourism: A Port wine tourism application proposal

Authors
Martins, J; Goncalves, R; Branco, F; Barbosa, L; Melo, M; Bessa, M;

Publication
JOURNAL OF DESTINATION MARKETING & MANAGEMENT

Abstract
Technological evolution has led to a significant transformation in tourism organizations, particularly in those who focus their activities on particular themes or segments, such as wine tourism. This can be transposed to Portuguese wine tourism organizations because the majority lack the necessary information and communication technologies (and inherent technologies) to become globally competitive. As highlighted in the literature, for a tourism experience to become memorable it must be emotional and immersive in such a way that the tourist becomes fully involved with the existing surroundings. This leads to the notion of using virtual reality experiences as triggers for the development of wine tourism. Considering the relevance of Portugal's Douro Valley to the country's wine tourism segment, a theoretical model that supports the implementation of multisensory (hence more immersive) virtual wine tourism experiences is developed. While considering the international success of Port wine tourism, this paper also presents a conceptualization of a multisensory virtual Port wine experience that includes a conceptual perspective and a technological solution proposal.

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