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This service develops advanced solutions in automation and industrial robotics, including handlers and mobile robots, and promotes the integration of control intelligent systems and sensing.

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Browsing CRIIS by Author "5490"
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    Classification of an Agrosilvopastoral System Using RGB Imagery from an Unmanned Aerial Vehicle
    ( 2019) Guimarães,N ; Emanuel Peres Correia ; Marques,P ; Telmo Oliveira Adão ; Pádua,L ; Sousa,JJ ; Sousa,A ; 5653 ; 5490
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    Deep Learning-Based Methodological Approach for Vineyard Early Disease Detection Using Hyperspectral Data
    ( 2018) Hruska,J ; Morais,R ; Telmo Oliveira Adão ; Sousa,A ; Sousa,JJ ; Padua,L ; Marques,P ; Emanuel Peres Correia ; 5653 ; 5490
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    Digital Reconstitution of Road Traffic Accidents: A Flexible Methodology Relying on UAV Surveying and Complementary Strategies to Support Multiple Scenarios
    ( 2020) Luís Filipe Pádua ; Sousa,JJ ; António Ribeiro Sousa ; Emanuel Peres Correia ; Telmo Oliveira Adão ; Hruska,J ; Vanko,J ; Sousa,J ; 7802 ; 5490 ; 5653 ; 5844
    The reconstitution of road traffic accidents scenes is a contemporary and important issue, addressed both by private and public entities in different countries around the world. However, the task of collecting data on site is not generally focused on with the same orientation and relevance. Addressing this type of accident scenario requires a balance between two fundamental yet competing concerns: (1) information collecting, which is a thorough and lengthy process and (2) the need to allow traffic to flow again as quickly as possible. This technical note proposes a novel methodology that aims to support road traffic authorities/professionals in activities involving the collection of data/evidences of motor vehicle collision scenarios by exploring the potential of using low-cost, small-sized and light-weight unmanned aerial vehicles (UAV). A high number of experimental tests and evaluations were conducted in various working conditions and in cooperation with the Portuguese law enforcement authorities responsible for investigating road traffic accidents. The tests allowed for concluding that the proposed method gathers all the conditions to be adopted as a near future approach for reconstituting road traffic accidents and proved to be: faster, more rigorous and safer than the current manual methodologies used not only in Portugal but also in many countries worldwide.
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    Effectiveness of Sentinel-2 in Multi-Temporal Post-Fire Monitoring When Compared with UAV Imagery
    ( 2020) Luís Filipe Pádua ; Joaquim João Sousa ; Emanuel Peres Correia ; António Ribeiro Sousa ; Telmo Oliveira Adão ; Guimaraes,N ; 7802 ; 5490 ; 5653 ; 5844 ; 6354
    Unmanned aerial vehicles (UAVs) have become popular in recent years and are now used in a wide variety of applications. This is the logical result of certain technological developments that occurred over the last two decades, allowing UAVs to be equipped with different types of sensors that can provide high-resolution data at relatively low prices. However, despite the success and extraordinary results achieved by the use of UAVs, traditional remote sensing platforms such as satellites continue to develop as well. Nowadays, satellites use sophisticated sensors providing data with increasingly improving spatial, temporal and radiometric resolutions. This is the case for the Sentinel-2 observation mission from the Copernicus Programme, which systematically acquires optical imagery at high spatial resolutions, with a revisiting period of five days. It therefore makes sense to think that, in some applications, satellite data may be used instead of UAV data, with all the associated benefits (extended coverage without the need to visit the area). In this study, Sentinel-2 time series data performances were evaluated in comparison with high-resolution UAV-based data, in an area affected by a fire, in 2017. Given the 10-m resolution of Sentinel-2 images, different spatial resolutions of the UAV-based data (0.25, 5 and 10 m) were used and compared to determine their similarities. The achieved results demonstrate the effectiveness of satellite data for post-fire monitoring, even at a local scale, as more cost-effective than UAV data. The Sentinel-2 results present a similar behavior to the UAV-based data for assessing burned areas.
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    Individual Grapevine Analysis in a Multi-Temporal Context Using UAV-Based Multi-Sensor Imagery
    ( 2020) Luís Filipe Pádua ; Sousa,JJ ; Emanuel Peres Correia ; António Ribeiro Sousa ; Telmo Oliveira Adão ; 5653 ; 5490 ; 7802 ; 5844
    The use of unmanned aerial vehicles (UAVs) for remote sensing applications in precision viticulture significantly increased in the last years. UAVs’ capability to acquire high spatiotemporal resolution and georeferenced imagery from different sensors make them a powerful tool for a better understanding of vineyard spatial and multitemporal heterogeneity, allowing the estimation of parameters directly impacting plants’ health status. In this way, the decision support process in precision viticulture can be greatly improved. However, despite the proliferation of these innovative technologies in viticulture, most of the published studies rely only on data from a single sensor in order to achieve a specific goal and/or in a single/small period of the vineyard development. In order to address these limitations and fully exploit the advantages offered by the use of UAVs, this study explores the multi-temporal analysis of vineyard plots at a grapevine scale using different imagery sensors. Individual grapevine detection enables the estimation of biophysical and geometrical parameters, as well as missing grapevine plants. A validation procedure was carried out in six vineyard plots focusing on the detected number of grapevines and missing grapevines. A high overall agreement was obtained concerning the number of grapevines present in each row (99.8%), as well as in the individual grapevine identification (mean overall accuracy of 97.5%). Aerial surveys were conducted in two vineyard plots at different growth stages, being acquired for RGB, multispectral and thermal imagery. Moreover, the extracted individual grapevine parameters enabled us to assess the vineyard variability in a given epoch and to monitor its multi-temporal evolution. This type of analysis is critical for precision viticulture, constituting as a tool to significantly support the decision-making process.
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    Machine learning classification methods in hyperspectral data processing for agricultural applications
    ( 2018) Hruska,J ; Sousa,JJ ; Telmo Oliveira Adão ; Cunha,A ; Morais,R ; Pádua,L ; Marques,P ; Emanuel Peres Correia ; Sousa,AMR ; 5490 ; 5653
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    MixAR
    ( 2019) Pádua,L ; Agrellos,L ; Sousa,JJ ; Narciso,D ; Telmo Oliveira Adão ; Magalhães,L ; Emanuel Peres Correia ; 5653 ; 5490
    MixAR, a full-stack system capable of providing visualization of virtual reconstructions seamlessly integrated in the real scene (e.g. upon ruins), with the possibility of being freely explored by visitors, in situ, is presented in this article. In addition to its ability to operate with several tracking approaches to be able to deal with a wide variety of environmental conditions, MixAR system also implements an extended environment feature that provides visitors with an insight on surrounding points-of-interest for visitation during mixed reality experiences (positional rough tracking). A procedural modelling tool mainstreams augmentation models production. Tests carried out with participants to ascertain comfort, satisfaction and presence/immersion based on an in-field MR experience and respective results are also presented. Ease to adapt to the experience, desire to see the system in museums and a raised curiosity and motivation contributed as positive points for evaluation. In what regards to sickness and comfort, the lowest number of complaints seems to be satisfactory. Models' illumination/re-lightning must be addressed in the future to improve the user's engagement with the experiences provided by the MixAR system.
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    MixAR: A Multi-Tracking Mixed Reality System to Visualize Virtual Ancient Buildings Aligned Upon Ruins
    ( 2019) Telmo Oliveira Adão ; Emanuel Peres Correia ; Agrellos,L ; Sousa,JJ ; Narciso,D ; Luís Filipe Pádua ; Magalhães,L ; 7802 ; 5653 ; 5490
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    Multi-Temporal Vineyard Monitoring through UAV-Based RGB Imagery
    ( 2018) Marques,P ; Pádua,L ; Morais,R ; Hruška,J ; Sousa,J ; Telmo Oliveira Adão ; Emanuel Peres Correia ; 5490 ; 5653
    This study aimed to characterize vineyard vegetation thorough multi-temporal monitoring using a commercial low-cost rotary-wing unmanned aerial vehicle (UAV) equipped with a consumer-grade red/green/blue (RGB) sensor. Ground-truth data and UAV-based imagery were acquired on nine distinct dates, covering the most significant vegetative growing cycle until harvesting season, over two selected vineyard plots. The acquired UAV-based imagery underwent photogrammetric processing resulting, per flight, in an orthophoto mosaic, used for vegetation estimation. Digital elevation models were used to compute crop surface models. By filtering vegetation within a given height-range, it was possible to separate grapevine vegetation from other vegetation present in a specific vineyard plot, enabling the estimation of grapevine area and volume. The results showed high accuracy in grapevine detection (94.40%) and low error in grapevine volume estimation (root mean square error of 0.13 m and correlation coefficient of 0.78 for height estimation). The accuracy assessment showed that the proposed method based on UAV-based RGB imagery is effective and has potential to become an operational technique. The proposed method also allows the estimation of grapevine areas that can potentially benefit from canopy management operations.
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    mySense: A comprehensive data management environment to improve precision agriculture practices
    ( 2019) Telmo Oliveira Adão ; Emanuel Peres Correia ; Sousa,JJ ; Pavon Pulido,N ; Lopez Riquelme,J ; Padua,L ; Morais,R ; Silva,N ; Mendes,J ; 5653 ; 5490
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    A pilot digital image processing approach for detecting vineyard parcels in Douro region through high-resolution aerial imagery
    ( 2018) Telmo Oliveira Adão ; Pádua,L ; Sousa,JJ ; Hruska,J ; Marques,P ; Emanuel Peres Correia ; 5653 ; 5490
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    Procedural Modeling of Buildings Composed of Arbitrarily-Shaped Floor-Plans: Background, Progress, Contributions and Challenges of a Methodology Oriented to Cultural Heritage
    ( 2019) Telmo Oliveira Adão ; Magalhães,L ; Emanuel Peres Correia ; Sousa,JJ ; Marques,P ; Luís Filipe Pádua ; 7802 ; 5490 ; 5653
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    Procedural Modeling of Buildings Composed of Arbitrarily-Shaped Floor-Plans: Background, Progress, Contributions and Challenges of a Methodology Oriented to Cultural Heritage
    ( 2019) Padua,L ; Emanuel Peres Correia ; Sousa,JJ ; Marques,P ; Telmo Oliveira Adão ; Magalhaes,L ; 5653 ; 5490
    Virtual models' production is of high pertinence in research and business fields such as architecture, archeology, or video games, whose requirements might range between expeditious virtual building generation for extensively populating computer-based synthesized environments and hypothesis testing through digital reconstructions. There are some known approaches to achieve the production/reconstruction of virtual models, namely digital settlements and buildings. Manual modeling requires highly-skilled manpower and a considerable amount of time to achieve the desired digital contents, in a process composed by many stages that are typically repeated over time. Both image-based and range scanning approaches are more suitable for digital preservation of well-conserved structures. However, they usually require trained human resources to prepare field operations and manipulate expensive equipment (e.g., 3D scanners) and advanced software tools (e.g., photogrammetric applications). To tackle the issues presented by previous approaches, a class of cost-effective, efficient, and scarce-data-tolerant techniques/methods, known as procedural modeling, has been developed aiming at the semi- or fully-automatic production of virtual environments composed of hollow buildings exclusively represented by outer façades or traversable buildings with interiors, either for expeditious generation or reconstruction. Despite the many achievements of the existing procedural modeling approaches, the production of virtual buildings with both interiors and exteriors composed by non-rectangular shapes (convex or concave n-gons) at the floor-plan level is still seldomly addressed. Therefore, a methodology (and respective system) capable of semi-automatically producing ontology-based traversable buildings composed of arbitrarily-shaped floor-plans has been proposed and continuously developed, and is under analysis in this paper, along with its contributions towards the accomplishment of other virtual reality (VR) and augmented reality (AR) projects/works oriented to digital applications for cultural heritage. Recent roof production-related enhancements resorting to the well-established straight skeleton approach are also addressed, as well as forthcoming challenges. The aim is to consolidate this procedural modeling methodology as a valuable computer graphics work and discuss its future~directions.
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    A rapid prototyping tool to produce 360º video-based immersive experiences enhanced with virtual/multimedia elements
    ( 2018) Telmo Oliveira Adão ; Pádua,L ; Fonseca,M ; Agrellos,L ; Sousa,JJ ; Magalhães,L ; Emanuel Peres Correia ; 5653 ; 5490
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    UAS-based photogrammetry of cultural heritage sites
    ( 2018) Pádua,L ; Sousa,JJ ; Telmo Oliveira Adão ; Morais,R ; Hruska,J ; Marques,P ; Sousa,AMR ; Lourenço,JM ; Emanuel Peres Correia ; 5490 ; 5653
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    Vineyard properties extraction combining UAS-based RGB imagery with elevation data
    ( 2018) Padua,L ; Marques,P ; Sousa,JJ ; Morais,R ; Hruska,J ; Telmo Oliveira Adão ; Bessa,J ; António Ribeiro Sousa ; Emanuel Peres Correia ; 5844 ; 5490 ; 5653
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    Vineyard Variability Analysis through UAV-Based Vigour Maps to Assess Climate Change Impacts
    ( 2019) Telmo Oliveira Adão ; Sousa,JJ ; Emanuel Peres Correia ; Sousa,A ; Pádua,L ; Marques,P ; Guimarães,N ; 5653 ; 5490
    Climate change is projected to be a key influence on crop yields across the globe. Regarding viticulture, primary climate vectors with a significant impact include temperature, moisture stress, and radiation. Within this context, it is of foremost importance to monitor soils’ moisture levels, as well as to detect pests, diseases, and possible problems with irrigation equipment. Regular monitoring activities will enable timely measures that may trigger field interventions that are used to preserve grapevines’ phytosanitary state, saving both time and money, while assuring a more sustainable activity. This study employs unmanned aerial vehicles (UAVs) to acquire aerial imagery, using RGB, multispectral and thermal infrared sensors in a vineyard located in the Portuguese Douro wine region. Data acquired enabled the multi-temporal characterization of the vineyard development throughout a season through the computation of the normalized difference vegetation index, crop surface models, and the crop water stress index. Moreover, vigour maps were computed in three classes (high, medium, and low) with different approaches: (1) considering the whole vineyard, including inter-row vegetation and bare soil; (2) considering only automatically detected grapevine vegetation; and (3) also considering grapevine vegetation by only applying a normalization process before creating the vigour maps. Results showed that vigour maps considering only grapevine vegetation provided an accurate representation of the vineyard variability. Furthermore, significant spatial associations can be gathered through (i) a multi-temporal analysis of vigour maps, and (ii) by comparing vigour maps with both height and water stress estimation. This type of analysis can assist, in a significant way, the decision-making processes in viticulture.