Browsing by Author "Jesus, Rui"
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- An interface to retrieve personal memories using an iconic visual languagePublication . Jesus, Rui; Romão, Teresa; Correia, NunoRelevant past events can be remembered when visualizing related pictures. The main difficulty is how to find these photos in a large personal collection. Query definition and image annotation are key issues to overcome this problem. The former is relevant due to the diversity of the clues provided by our memory when recovering a past moment and the later because images need to be annotated with information regarding those clues to be retrieved. Consequently, tools to recover past memories should deal carefully with these two tasks. This paper describes a user interface designed to explore pictures from personal memories. Users can query the media collection in several ways and for this reason an iconic visual language to define queries is proposed. Automatic and semi-automatic annotation is also performed using the image content and the audio information obtained when users show their images to others. The paper also presents the user interface evaluation based on tests with 58 participants.
- Aplicação colaborativa em cenário real para animação de um cenário virtualPublication . Gomes, Telmo; Júnior, Carlos; Jesus, Rui; Jorge, PedroAs aplicações mais populares de mistura de cenários reais com cenários virtuais têm sido as aplicações de realidade aumentada e de realidade mista (realidade aumentada + virtualidade aumentada). Este trabalho mistura a realidade com ambientes virtuais numa aplicação colaborativa para duas pessoas. O projeto tem como objetivo o desenvolvimento de uma aplicação para navegação em ambientes virtuais através da interpretação de movimentos reais de uma pessoa. Estes movimentos são capturados por uma câmara, interpretados com algoritmos de processamento de vídeo e transmitidos para a interface de animação e lógica de jogo do Blender [1] (GameLogic [2]). Este artigo descreve a aplicação e apresenta resultados experimentais que ilustram o seu desempenho.
- Arrayed graphene enhanced surface plasmon resonance for sensing applicationsPublication . Fantoni, Alessandro; Vygranenko, Yuri; Maçarico, António; Serafinelli, Caterina; Fernandes, Miguel; Mansour, Rima; Jesus, Rui; Vieira, ManuelaCombination of carbon-based nanomaterials (CNMs) with AuNPs has been demonstrated to enhance the LSPR response and facilitate the functionalization with specific and selective antibodies. Also, the introduction of CNMs in the plasmonic layer allows tuning of the LSPR central frequency. Joining the double dependence of the LSPR on the MNPs size and the presence of CNMs, it is possible to create a set of plasmonic layers whose LSPR wavelengths are distributed in a spectral range of few tenth of nanometers. This consideration paves the way to an LSPR sensor with an arrayed structure, where each element maximizes its specific LSPR at its own wavelength. Illumination with a broad light source produces a different response in each one of the elements. The working process underlying the sensing operation is that each element of the sensor array acts like a band-stop optical filter for a specific wavelength. The output can be extracted by the application of an image analysis approach to the spatially modulated light crossing the sensor area, based on a color recognition algorithm. A change in the refractive index over the sensor array will shift the rejection band of the sensing elements. An automatized method for color recognition can support the analysis of the refractive index variations yielding the final sensor output. A figure of merit, highlighting the LSPR central wavelength and spectral extension for different LSPR configurations, is also obtained for different sizes of the AuNPs and different flavors of CNMs.
- ARZombie: A mobile augmented reality game with multimodal interactionPublication . Cordeiro, Diogo; Correia, Nuno; Jesus, RuiAugmented reality games have the power to extend virtual gaming into real world scenarios with real people, while enhancing the senses of the user. This paper describes the ARZombie game developed with the aim of studying and developing mobile augmented reality applications, specifically for tablets, using face recognition interaction techniques. The goal of the ARZombie player is to kill zombies that are detected through the display of the device. Instead of using markers as a mean of tracking the zombies, this game incorporates a facial recognition system, which will enhance the user experience by improving the interaction of players with the real world. As the player moves around the environment, the game will display virtual zombies on the screen if the detected faces are recognized as belonging to the class of the zombies. ARZombie was tested with users to evaluate the interaction proposals and its components were evaluated regarding the performance in order to ensure a better gaming experience.
- Authentication of Art: assessing the performance of a machine learning based authentication methodPublication . Chen, Ailin; Jesus, Rui; Vilarigues, MárciaThis paper compares the test results generated by applying the method for the authentication of paintings by Portuguese artist Amadeo de Souza Car-doso in the interest of exploring the generalisation properties of the algorithm on other artists or genres. This sets the base for the method to be improved and de-veloped accordingly in future applications for a broader audience in a wider set-ting. The obtained results show that the classifier obtained from the algorithm using paintings appears not to be directly applicable to drawings of the same art-ist. When the classifier is retrained for a different genre like Chinese paintings or artists like van Gogh, the algorithm appears to perform as well as the classifier on Amadeo paintings, i.e. the algorithm is sufficient for the classification of a specific type of artist or genre.
- Colour and image processing for output extraction of a LSPR sensorPublication . Mansour, Rima; Stojkovic, Vladan; Vygranenko, Yuri; Lourenço, Paulo; Jesus, Rui; Fantoni, AlessandroSensors based on the Local Surface plasmon Resonance (LSPR) are attractive due to their simple structure and good sensitivity, but the expensive optoelectronic part of the device is limiting the practical applications. There is a need for new strategies to bring the excellent detection properties of LSPR sensors to the playground of low-cost devices and materials. In this work, it is proposed a novel approach to the output extraction of from LSPR sensor whose sensing element is composed by metal nanoparticles (MNPs). Illuminated with an incident broad light source, the sensor produces a spectral transmission output where the MNPs act like a band-stop optical filter for a specific wavelength. An alteration of the refractive index in the surrounding medium corresponds directly to a shift of the filtering rejection band, which corresponds to a slight change in the colour of the light transmitted by the sensor elements. This colour change can be captured by a CMOS photo-camera, used as an image sensor. It is proposed in this paper an approach based on an automatized image processing algorithm for colour change detection, yielding to a system capable of detecting refractive index variations, avoiding the use of expensive spectrometers. The algorithm comprises three stages: (1) Region of interest detection: images are first cropped using the Otsu threshold binary image to remove the uninteresting areas in the image. (2) Image segmentation: using the watershed algorithm, the sensor elements (sample) area is detected automatically in the cropped image. The segmentation is done using the gradient image, where the watershed markers are the regions of low gradient and barriers are the areas of high values inside the image. (3) The resulted sample region is then processed to find its average or dominant LAB colour and then compare it to its corresponding sample image immersed in different mediums using the colour difference measurement CIEDE2000.
- Convolutional neural network-based pure paint pigment identification using hyperspectral imagesPublication . Chen, Ailin; Jesus, Rui; VilariguesThis research presents the results of the implementation of deep learning neural networks in the identification of pure pigments of heritage artwork, namely paintings. Our paper applies an inno vative three-branch deep learning model to maximise the correct identification of pure pigments. The model proposed combines the feature maps obtained from hyperspectral images through multi ple convolutional neural networks, and numerical, hyperspectral metric data with respect to a set of reference reflectances. The results obtained exhibit an accurate representation of the pure pre dicted pigments which are confirmed through the use of analytical techniques. The model presented outperformed the compared coun terparts and is deemed to be an important direction, not only in terms of utilisation of hyperspectral data and concrete pigment data in heritage analysis, but also in the application of deep learning in other fields.
- Development and evaluation of a mobile application with augmented reality for guiding visitors on hiking trailsPublication . Silva, Rute; Jesus, Rui; Jorge, PedroTourism on the island of Santa Maria, Azores, has been increasing due to its characteristics in terms of biodiversity and geodiversity. This island has several hiking trails; the available information can be consulted in pamphlets and physical placards, whose maintenance and updating is difficult and expensive. Thus, the need to improve the visitors’ experience arises, in this case, by using the technological means currently available to everyone: a smartphone. This paper describes the development and evaluation of the user experience of a mobile application for guiding visitors on said hiking trails, as well as the design principles and main issues observed during this process. The application is based on an augmented reality interaction model providing visitors with an interactive and recreational experience through Augmented Reality in outdoor environments (without additional marks in the physical space and using georeferenced information), helping in navigation during the route and providing updated information with easy maintenance. For the design and evaluation of the application, two studies were carried out with users on-site (Santa Maria, Azores). The first had 77 participants, to analyze users and define the application’s characteristics, and the second had 10 participants to evaluate the user experience. The feedback from participants was obtained through questionnaires. In these questionnaires, an average SUS (System Usability Scale) score of 83 (excellent) and positive results in the UEQ (User Experience Questionnaire) were obtained.
- Exploring the behavior of the player to change the course of a gamePublication . Beleza Sousa, João; Jesus, RuiThis paper proposes and discusses a horse racing game which explores the user behavior when playing, to change the gameplay. The game includes a module to capture and analyze, in real time, the body movement and the audio produced by the player. The paper describes the rational and design principles for the game and presents the main issues of the study conducted during the development of the game.
- Features combination for art authentication studies: brushstroke and materials analysis of Amadeo de Souza-CardosoPublication . Montagner, Cristina; Jesus, Rui; Correia, Nuno; Vilarigues, Márcia; Macedo, Rita; Melo, Maria JoãoThis work presents a tool to support authentication studies of paintings attributed to the modernist Portuguese artist Amadeo de Souza-Cardoso (1887-1918). The strategy adopted was to quantify and combine the information extracted from the analysis of the brushstroke with information on the pigments present in the paintings. The brushstroke analysis was performed combining Gabor filter and Scale Invariant Feature Transform. Hyperspectral imaging and elemental analysis were used to compare the materials in the painting with those present in a database of oil paint tubes used by the artist. The outputs of the tool are a quantitative indicator for authenticity, and a mapping image that indicates the areas where materials not coherent with Amadeo's palette were detected, if any. This output is a simple and effective way of assessing the results of the system. The method was tested in twelve paintings obtaining promising results.
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