Pablo Rodríguez-Gonzálvez research stay at 3D Optical Metrology (3DOM, Italy)

Pablo Rodríguez Gonzálvez research stay at 3D Optical Metrology
Research stay at the Bruno Kessler Foundation (FBK) and its 3D Optical Metrology (3DOM) research unit from September to November, 2014, under the supervision of Dr. Fabio Remondino. 

 The stay was focused in photogrammetry, surveying, laser scanning and 3D modelling. The specific research topics were:

 

  • 3D documentation of complex World War I scenarios in the framework of the VAST Project (VAlorizzazione Storia e Territorio – Valorization of History and Landscape, http://vast.fbk.eu/). Concretely, the tasks were focused in the efficient complexity reduction for information dissemination purposes, but keeping the maximum amount of significant information. As result of the Lusern fort documentation, a simplification pipeline was proposed in order to prioritize the mesh level of detail or a smooth continuous geometry, but always with the minimum number of triangles according to a specific spatial resolution. Also, photogrammetric tests to survey and model underground tunnels as a low-cost alternative were carried out, and evaluated in terms of a-prioir and a-posteriori error. 
  • Geometric assessment of a Mobile Mapping System (MMS) using advanced statistical methods. The new system VMX-450 (Riegl) precision and accuracy was evaluated in the framework of a challenge test site: the historic city centre of Trento. Non-normal statistics were employed thus a more appropriate assessment of precision and accuracy, and contrasted against reference measures are derived from photogrammetric and Terrestrial Laser Scanning (TLS) surveys. 
  • Characterization of a spherical camera for the 3D reconstruction of different environments. Several tests for the camera geometric characterization were carried out, as well automatic 3D reconstruction of indoor and outdoor scenes (Trento cathedral).

 

Pablo Rodríguez Gonzálvez research stay at 3D Optical Metrology

Geometric assessment of a Mobile Mapping System (MMS) using advanced statistical methods. The new system VMX-450 (Riegl) precision and accuracy was evaluated in the framework of a challenge test site: the historic city centre of Trento. Non-normal statistics were employed thus a more appropriate assessment of precision and accuracy, and contrasted against reference measures are derived from photogrammetric and Terrestrial Laser Scanning (TLS) surveys.

Pablo Rodríguez Gonzálvez research stay at 3D Optical Metrology

Luis Javier Sánchez Aparicio research stay at Historical and Masonry Structures group (Guimarães,Portugal)

Research stay of Luis Javier Sánchez Aparicio at the University of Minho (Portugal) and its research group Historical and Masonry Structures (http://www.hms.civil.uminho.pt/) from March to June, 2014, under the supervision of Dr. Luís F. Ramos.

During this stay, Luis Javier was focused on developing calibration procedures of Finite Elements Models and the integration of dynamical and geomatic approaches in the evaluation of structural damages in constructions.

  • During the first stage, a complete geometrical characterization (trough Terrestrial Laser Scanner) and historical survey were carried out in the Saint Torcato church, with the aim of develop a complete and complex numerical simulation which encloses phase analysis and a complete characterization of the complex mechanical soil behavior.

S.Torcato_4

 

  • A second stage was focused on the structural evaluation of the prototype Ponta Lumis, with the combination of dynamical and static campaigns. During this stage, a hybrid calibration system was developed, which combined static, dynamic and damage functions in order to improve the numerical simulations.
  • Later, a third stage was focuses on the Digital Image Correlation approach, with the aim of develop mechanical tests Also, geometrical campaigns were carried out on masonry specimens to assist in the development of a new approach, called Tube Jack, with the aim of replacing the traditional Flat Jack test: (http://www.sciencedirect.com/science/article/pii/S0963869513000601).
  • Finally, a geometrical and dynamical analysis was performed in the Keep tower of the Guimarães` Castle. In order to  improve the actual structural knowledge of the construction and also develop geometrical strategies based on NURBs for numerical simulations.

IMG_1963Ponta_lumis

 

 

 

 

 

 

 

 

Susana del Pozo Aguilera research stay at Delft University of Technology (TuDelft, The Netherlands)

 Susana del Pozo Aguilera research stay at Delft University

Susana Del Pozo Aguilera carried out a research stay at the Delft University of Technology (TuDelft, The Netherlands) to collaborate with the Geoscience and Remote Sensing Department from March to June 2014 under the supervision of Dr. Roderik Lindenbergh. 

The stay was mainly focused in the remote sensing, multispectral close-range and characterization of outcrops fields. The specific research topics were:

Satellite remote sensing analysis. The first period was focused on spectral satellite data analysis. The aim of these tests was provide answer to the following questions: What was the best electromagnetic region of the spectrum to discretize sedimentary rocks and what was the most suitable satellite for rock mapping.  Images from different satellite (EO1-Hyperion (220 bands: 0.4-2.5 μm), ASTER (14 bands: 0.52-11.65 µm) and Landsat 8 (11 bands: 0.433-12.5 µm)) were tested trying to choose the greater spatial resolution data that were available for the study area (La Motte-Chalancon, France). As a result, 30-m spatial resolution images from Landsat 8 were classified trying to locate outcrops of sedimentary rocks in the area. Finally, results were linked with those obtained in the second period of the stay to draw meaningful conclusions of remote sensing in the field of geology.

Susana del Pozo Aguilera research stay at Delft University

Characterization of outcrops by close-range multispectral analysis. During the second period, a particular handheld spectral camera was used covering the VIS-VNIR range to assess its suitability in rocks studies. Hundreds of images of 12 different rock formations were taken during a two weeks stay in the Drôme region in France. The camera was previously calibrated to get physical values (radiances or reflectances) instead of digital levels from the studied surfaces. The spectral range provided by its 6 bands (0.530-0.801 µm) proved challenging and difficult since the SWIR range is the ideal for rocks studies. Good results were finally obtained for the discrimination between limestones and marlstones. In conclusion, the possibilities and limitations of the used camera for distinguishing sedimentary rocks were rigorous analysed and clearly defined.

Susana del Pozo Aguilera research stay at Delft University

Susana del Pozo Aguilera research stay at Delft University

Diego González Aguilera research stay at French National Institute for Research in Computer Science and Control (INRIA, France)

 Diego González Aguilera research stay at French National Institute

Diego Gonzalez Aguilera was invited by the INRIA (French National Institute for Research in Computer).

Science and Control) (Dr. Peter Sturm) in Grenoble (France) for carrying out a research stay during 3 months (April-July, 2005). The research was focused on 3d laser scanner and image-based modelling integration. In particular, photogrammetric methods and algorithms were related and adapted to cope with 3d point clouds coming from laser scanners, trying to advance solutions to integrate 3D laser scanner data and 2D colour images. Particularly, the image-based modelling pipeline constitutes a very portable and low-cost technique which consists on the 3D reconstruction of objects from one or more images. In this sense, several assumptions have to be solved: from camera self-calibration and image point measurements, to 3D points cloud generation, surface extraction and texturing. In this way, image-based modelling is a technique that has undergone a big growth in the last years. This promising evolution could be portrayed by the following issues:

 

  • New technological neighbors and new relations among these: Photogrammetry, Image Processing, Remote Sensing, Computer Graphics, Computer Vision, etc.
  • New algorithms and methods have emerged in order to achieve automatization and provide new products.
  • Despite the raising paradigm covered by the ‘full automatization’ target (well described by the motto coined by Ackerman ‘Redundancy vs. Intelligence’ or the one proposed by Schenk ‘Quantity vs. Quality’), there is a spreading field in which architects, archaeologists, risk preventers, land managers,…and many others non-skilled geomatic professionals may participate in a passive (users) or even active (designers, developers) fashion.

 

Diego González Aguilera research stay at French National Institute

Finally at the end of the stay, two keynotes were given about 3d reconstruction from a single view and Aerial images for 3D modelling of Cultural Heritage.

New technological neighbors and new relations among these: Photogrammetry, Image Processing, Remote Sensing, Computer Graphics, Computer Vision, etc.New technological neighbors and new relations among these: Photogrammetry, Image Processing, Remote Sensing, Computer Graphics, Computer Vision, etc.New technological neighbors and new relations among these: Photogrammetry, Image Processing, Remote Sensing, Computer Graphics, Computer Vision, etc.

Diego González Aguilera research stay at French National Institute

 

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Análisis termográfico de edificios

 

El uso de la termografía infrarroja comMapaEnergeticoo técnica sobradamente provada para la inspección de edificios y localización de patologías como fugas de aire, humedades, etc. Nos permite realizar un examen visual “in-situ” de calidad de los objetos de estudio gracias a la posibilidad de visualizar en tiempo real los resultados pudiendo detectar sin dificultad los desperfectos o elementos característicos de estos. Estas técnicas de medición cualitativa nos proporcionan la posibilidad de realizar inspecciones rápidas y eficaces sin contacto directo con el objeto y de forma no destructiva, lo que disminuye tanto el riesgo de incidentes para los operarios como los daños producidos en los propios objetos de estudio ocasionados por otras técnicas intrusivas. Además, también se ha demostrado la utilidad de la termografía infrarroja como técnica puramente de medida a través de su utilización para el cálculo de propiedades termofísicas de materiales tales como difusividad y transmitancia térmica.

En el caso de termografía cualitativa, las publicaciones existentes tratan de estudios realizados in-situ, principalmente en edificios históricos o elementos del patrimonio cultural, mientras que los estudios cualitativos se realizan, en la mayor parte de los casos, en laboratorios sobre muestras de tamaño limitado. En aquellos casos en los que se han realizado estudios termográficos cuantitativos sobre edificios in-situ, los valores de temperatura son empleados con el objetivo de obtener propiedades termofísicas (conductancia térmica) reales del cerramiento, sin embargo su distribución espacial no es considerada.

Conjugar ambas aplicaciones permitirá la automatización del cálculo de pérdidas de calor a partir de las temperaturas medidas con una cámara termográfica. De este modo, no solo se usa la termografía para representar el estado de la pared, sino que también se usan los valores de temperatura contenidos en la termografía para la extracción de parámetros métricos del edificio en estudio, por lo que la hibridación de la información termográfica con el material cartográfico de precisión permitiría extraer la geometría real del objeto de estudio con textura termográfica, pudiendo así realizar mediciones precisas de los elementos de interés directamente sobre el resultado obtenido.

 

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Estudios como el publicado por EuroACE en 2010 colocan la mejora de la eficiencia energética en edificación en cabeza de las acciones necesarias para la reducción de emisiones de gases del efecto invernadero y gasto energético, así como para servir de empuje a la generación de empleo. Especial es el caso del parque de edificios ya construidos, la mayoría procedente de los años 1940-80, con normativa inexistente y recursos escasos. En ellos las obras de rehabilitación energética pueden suponer un ahorro de hasta el 75% en consumo de energía. En España existen 13 millones de viviendas susceptibles de intervención, cuya rehabilitación energética supondría una reducción de las emisiones del sector del 34% con respecto al año 2001.

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Building thermographic analysis

 

 

The use of infraMapaEnergeticored thermography as a widely tested technique for building inspection and location of pathologies such as air leakage and moisture allows the performance of  quality “in-situ” visual examination of the objects under study due to the possibility of obtaining real-time results, being able to detect without difficulty damages or material characteristics. This qualitative measurement technique provides the capability of doing quick, effective and non-destructive inspection without direct contact with the object under study, decreasing the risk of incidents to operators and the damage of the objects comparing with other intrusive techniques. Furthermore, the utility of infrared thermography as a measurement technique has been proved by its use for the determination of the thermophysical properties of materials such as diffusivity and thermal transmittance.

In the qualitative approach, some authors have performed in-situ studies, mainly in historical buildings or cultural heritage elements, whereas quantitative studies are performed mainly in laboratories with limited size samples. In those cases where quantitative thermography studies were performed in-situ, temperature values were employed in order to obtain the real thermophysical properties (thermal conductance) of the building envelope, but their spatial distribution is not considered.

Combine both applications will enable the automation of the heat loss computation from the measured temperatures with a thermographic camera. Thus, the thermography is not only used to represent the state of the wall, but also temperature values represented on the thermography for extracting the metric parameters of the study object so the hybridization of the thermographic information with precise cartographic material would  allow to extract the actual geometry of the object of study with thermal texture, being able to make accurate measurements of the elements of interest directly on the obtained results.

 

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Studies such as the one published by EuroACE in 2010, places improved energy efficiency in building construction at the top of the list of actions that need to be taken to reduce greenhouse gases and energy costs, in addition to acting as a stimulus to generate employment. In particular is the case of existing buildings stock, most of which dates back to the period 1940-80, constructed using non-existent standards and scarce resources. Here, energy refurbishment works could represent a saving of up to 75% in energy consumption. In Spain there are 13 million homes that could be the subject of intervention, where energy refurbishment could result in a reduction in sector emissions of 34% compared to 2001.

 

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Ventana modal ingles
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Ventana modal español
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Mobile Laser System (MLS) applied to urban tree inventory

In urbanized Western Europe trees are considered an important component of the built-up environment. This also means that there is an increasing demand for tree inventories. Laser mobile mapping systems provide an efficient and accurate way to sample the 3D road surrounding including notable roadside trees. In this research line, a processing chain aiming at the extraction of tree locations and tree sizes from laser mobile mapping data is reached.

  • Vegetation extraction

MLS_urban_3

  • Tree parameter extraction

MLS_urban_2

 

Such steps, in combination with code optimization are expected to be sufficient to reach the final goal of automatized estimation of features sampled by mobile mapping at a rate that matches the acquisition speed and at a quality that matches the result of a human operator.

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