Person: Álvarez Fernández-Balbuena, Antonio
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First Name
Antonio
Last Name
Álvarez Fernández-Balbuena
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Óptica y Optometría
Department
Óptica
Area
Optica
Identifiers
52 results
Search Results
Now showing 1 - 10 of 52
Item Mathematical Model Applied To Improve The Natural Lighting Design(International Journal of Sustainable Development and Planning, 2017) García Fernández, Berta; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, AntonioDaylighting must be considered as the greenest way to illuminate any space and one of the most important architectural design challenges and opportunities. Human life is strongly influenced by natural lighting, and nowadays we have to add to this factor the importance of energy conservation and pollution reduction objectives. The development of hollow light guides offers people the advantages of natural lighting and the benefits of reduced energy consumption systems, providing changes in architectural form of spaces where sunlight does not have direct access. Hollow Cylindrical Prismatic Light Guides (CPLGs) are transparent optical components able to transmit high diameter light beams in daylight buildings applications without relevant losses. The goal of this paper is to show a novel lighting design based on hollow prismatic light pipes, which let daylight to be introduced inside of buildings. An improved mathematical modelling to predict light transmission efficiency based on realistic software simulations and experimental models is presented.Item Improvement of driver night vision in foggy environments by structured light projection.(Heliyon, 2022) Quintana Benito, Jaime; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Moliní, DanielNowadays, fog is still a natural phenomenon that hinders our ability to detect targets, particularly in the field of driving where accidents are increasing. In the literature we find different studies determining the range of visibility, improving the quality of an image, determining the characteristics of fog, etc. In this work we propose the possibility of using a structured lighting system, on which we project the light towards the target, limiting the field lighting. We have developed a scattering light propagation model to simulate and subsequently study the veil luminance, generated by backscattering, to predict the decrease in visibility. This simulation considers the type of fog, the relative orientation of various elements (observer, light source and targets). We have built a fog chamber to validate the experimental params of the described system. The results obtained from both the simulation and the experimental measurements demonstrate that it is possible to obtain a high contrast enhancement for viewing a target when illuminated as described. Clearly, this kind of lighting technology will improve the road safety in foggy night environments. The results of this work can also be extrapolated to any situation in which the visibility of an observer is compromised by the environment, such as heavy rain, smoke from fires, among others.Item Advanced daylighting evaluation applied to cultural heritage buildings and museums: Application to the cloister of Santa Maria El Paular(Renewable Energy, 2016) Mayorga Pinilla, Santiago; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, Antonio; Hernández Raboso, Gabriel; Herráez, Juan Antonio; Azcutia, Marta; García Botella, ÁngelA method to evaluate the risk of using daylight in museums and cultural heritage exhibitions is presented along this study. Although daylight is an ecological and sustainable source of energy and sometimes also an intrinsic part of the artwork, the use of Natural lighting may cause damages in them due to the difficulty of controlling its variability. The developed method quantifies the damage produced to the artworks by daylight compared to artificial light taking into account the level of radiation and its spectral distribution in space and time by comparison with the damage caused by an Illuminant A (Global Risk Factor). The method, applied to the permanent paintings exhibition in the cloister of the fifteenth century of the Monastery of Santa Maria de El Paular, certifies that the control and exploitation of Natural Light should consider an optimal balance between exposure and damage.Item Analytical method to measure bending deformations in prismatic optical films(Chinese Optics Letters, 2016) García Fernández, Berta; Álvarez Fernández-Balbuena, Antonio; Vázquez Molini, DanielThe aim of this work is to provide an analytical method based on experimental measurements in order to obtain the prismatic film deformation for different curvatures of Hollow Cylindrical Prismatic Light Guides (CPLG). To conform cylindrical guides is necessary bend the film to guide the light, changes induced by curving the film give rise to deformation shifts. Light losses affected by deformation has been experimentally evaluated and numerically analyzed. The effect of deformation in prism angle is specially increased for CPLG of curvatures higher than 20 m-1. An experimental method for accurate transmittance measurements related to bending is presented.Item Horizontal daylighting system for office buildings(Energy and Buildings, 2013) Vázquez Molini, Daniel; González Montes, Mario; Álvarez Fernández-Balbuena, AntonioThis work is focused on a sunlight collection device for solar lighting systems aimed at non-residential buildings. The design takes advantage of solar energy that reaches the facade of the building for lighting purposes, thereby reducing building energy consumption by supplementing it with clean, renewable energy. This daylighting system's structure comprises a light collector located outside the vertical facade of the building, a modular light guide that runs along the horizontal false ceiling and light extractor luminaires strategically positioned along the guide. The system is configured specifically to the particular characteristics of each building (façade orientation, latitude and longitude) to optimize the global performance. The present paper describes in detail the anidolic collecting system as a part of the comprehensive daylighting system. However the entire daylighting system has been completely developed and experimentally tested, and its prototype is currently integrated into Lledó S.A company's facilities.Item Efficient and sustainable energy lighting solutions(Proceedings of SPIE, 2019) García Botella, Ángel; Vázquez Moliní, Daniel; García Fernández, Berta; Álvarez Fernández-Balbuena, AntonioThe electric lighting is responsible for 15% of the electricity consumption, the efficiency in this sector has a good progress in recent years, it can still improve more. Conventional energy sources are polluting and limited, so it is essential to use less aggressive energies with the environment. In lighting, this premise is being implemented in a cross-cutting manner, but in response to varied and sometimes contradictory interests. The development of lighting devices based on solar radiation is an inalienable objective, as is the use of artificial lighting sources that are clean with the environment. To achieve these two objectives, it is essential to know and study the design techniques of non-image optics. In the present work we present new systems design techniques and lighting elements: ray tracing optimization technique, light vector field technique. As well as its implementation and application in various areas of lighting: lighting in office buildings, libraries museums. We show that renewable energy strategy in the field of lighting not only produce energy save, also produce good effects in other aspects of human life like well-being, productivity and heritage conservation.Item Iluminar obras de arte mejorando la conservación. El proyecto Zeus(2015) Benítez, Anton J.; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, AntonioLa iluminación de obras de arte se enfrenta al reto de resultar adecuada para la exhibición y de minimizar en lo posible los daños a la superficie y los materiales que las componen. En esta encrucijada, en la que la investigación es imprescindible tanto en tecnología como acerca de la recepción por parte del público, el proyecto Zeus trata de obtener una precisa información sobre el color de la obra, y trasladarla a un modelo de iluminación individualizado punto a punto, que permite simular condiciones precisas y compensar efectos indeseables del deterioro, minimizando la luz absorbida por la obra.Item Improvement of driver night vision in foggy environments by structured light projection(Heliyon, 2022) Quintana Benito, Jaime; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Moliní, DanielNowadays, fog is still a natural phenomenon that hinders our ability to detect targets, particularly in the field of driving where accidents are increasing. In the literature we find different studies determining the range of visibility, improving the quality of an image, determining the characteristics of fog, etc. In this work we propose the possibility of using a structured lighting system, on which we project the light towards the target, limiting the field lighting. We have developed a scattering light propagation model to simulate and subsequently study the veil luminance, generated by backscattering, to predict the decrease in visibility. This simulation considers the type of fog, the relative orientation of various elements (observer, light source and targets). We have built a fog chamber to validate the experimental params of the described system. The results obtained from both the simulation and the experimental measurements demonstrate that it is possible to obtain a high contrast enhancement for viewing a target when illuminated as described. Clearly, this kind of lighting technology will improve the road safety in foggy night environments. The results of this work can also be extrapolated to any situation in which the visibility of an observer is compromised by the environment, such as heavy rain, smoke from fires, among others.Item High-Dynamic-Range Spectral Reflectance for the Segmentation of Paint Pigment: Application to Dalí’s Oil Painting Dos Figuras (1926)(Sensors, 2023) Álvarez Fernandez-Balbuena, Antonio; Gómez Manzanares, Ana; Martínez Antón, Juan Carlos; García Gómez-Tejedor, Jorge; Mayorga Pinilla, Santiago; Durán Roque, Humberto; Vázquez Moliní, Daniel; Álvarez Fernández-Balbuena, Antonio; Martínez Antón, Juan Carlos; Vázquez Molini, DanielRestorers and curators in museums sometimes find it difficult to accurately segment areas of paintings that have been contaminated with other pigments or areas that need to be restored, and work on the painting needs to be carried out with minimum possible damage. It is therefore necessary to develop measurement systems and methods that facilitate this task in the least invasive way possible. The aim of this study was to obtain high-dynamic-range (HDR) spectral reflectance and spatial resolution for Dalí’s painting entitled Two Figures (1926) in order to segment a small area of black and white pigment that was affected by the contact transfer of reddish pigment from another painting. Using Hypermatrixcam to measure the HDR spectral reflectance developed by this research team, an HDR multispectral cube of 12 images was obtained for the band 470–690 nm in steps of 20 nm. With the values obtained for the spectral reflectance of the HDR cube, the colour of the area of paint affected by the transfer was studied by calculating the a*b* components with the CIELab system. These a*b* values were then used to define two methods of segmenting the exact areas in which there was a transfer of reddish pigment. The area studied in the painting was originally black, and the contamination with reddish pigment occupied 13.87% to 32% of the total area depending on the selected method. These different solutions can be explained because the lower limit is segmentation based on pure pigment and the upper limit considers red as an exclusion of non-black pigment. Over- and under-segmentation is a common problem described in the literature related to pigment selection. In this application case, as red pigment is not original and should be removed, curators will choose the method that selects the highest red area.Item Optimization of daylight utilization in energy saving application on the library in faculty of architecture, design and built environment, Beirut Arab University(Alexandria Engineering Journal, 2018) Omar, Osama; García Fernández, Berta; Álvarez Fernández-Balbuena, Antonio; Vázquez Molini, DanielConsidering that reading and research are the main functions of use in libraries of all educational facilities, proper lighting becomes a crucial factor in the overall success of a library design. In this framework, daylight is essential for both energy saving and improvement of the quality of life in newer buildings where visual tasks are more diverse, and technology poses new types of lighting requirements. Furthermore, emphasis on the importance and methods used to utilize energy will be implemented; provided by nature as the first step in achieving optimum energy saving and reducing our dependence on fossil fuels. Thus, this study will examine the conditions of indoor daylight and the library’s energy performance in the faculty of Architecture, Design and Built Environment, Beirut Arab University with various architectural elements including space depth, window size, external obstruction angle, and glazing visible transmittance. This is done by first analysing the existing situations of daylighting (using Autocad Ecotect software), the situation of the artificial lighting inside the space (using Dial DIALux software), and the behavior of the users throughout the day (using Hobo loggers). Then, the outcomes will be analyzed to specify the challenges, therefore providing solutions related to environmental, technological, and energy saving as well as sustainable and green building designs. As a result, daylight designs based on hollow prismatic light guides are proposed. These designs act as luminaires increasing guide efficiency and uniformity distribution of natural light into the library spaces. The proposed designs are configured and analyzed by ray-tracing simulations for achieving high illumination levels and uniform lighting in the working plane of the library.