Use of Matrices for the Adaptation of Video-based Photogoniometric Measurements to a Variable Referential

Digital video based luminance mapping systems require the establishment of a precise relation between the considered spatial referential and the associated pixel coordinates on the image, that may vary with the measurement conditions. In this paper, an adaptation of the image calibration according to the referential variations is proposed, based on the use of a set of matrices individually associated to each spatial coordinate. This approach is given through an application example on a recent digital imaging-based bi-directional photogoniometric device

Light distribution through advanced fenestration systems

Most energy-saving applications of advanced fenestration systems, e.g. solar blinds, novel types of glazing and daylight redirecting devices, require a precise knowledge of their directional light-transmission features. These photometric properties are described by a Bi-directional Transmission Distribution Function (BTDF), which is experimentally assessed by a bi-directional photogoniometer. As such a function represents a heavy amount of data, there is a need for a synthetic and intuitive visualization of a system's transmission behaviour. For this purpose, four kinds of graphical representations have been created and are presented in this paper. These are based on bi-directional data assessed by a novel digital imagingbased photogoniometer, whose measurement principle allows a continuous knowledge of the whole transmission space, and therefore an appreciable liberty in data processing. The geometric properties of the different representations are described, together with the corresponding image operations. The information extraction from these graphical visualizations is given through a comparison example between a conventional venetian blind and an optimized prototype. La plupart des mesures d'économie d'énergie appliquées aux systèmes de fenêtrage de pointe, comme les stores pare-soleil, les nouveaux types de vitrage et les dispositifs de réorientation de l'éclairage naturel, exigent une connaissance précise des caractéristiques de la transmission directionnelle de la lumière. Ces propriétés photométriques correspondent à la fonction bidirectionnelle de transmission (BTDF) qui est évaluée expérimentalement par un photogoniomètre bidirectionnel. Une telle fonction représentant un très grand volume de données, une visualisation synthétique et intuitive du comportement de la transmission d'un système devient nécessaire. A cet effet, quatre types de représentations graphiques ont été créés et sont présentés dans cet article. Ils reposent sur des données bidirectionnelles évaluées par un nouveau photogoniomètre à imagerie numérique dont le principe de mesure permet une connaissance continue de l'ensemble de l'espace de transmission permettant ainsi une liberté appréciable dans le traitement des données. Les propriétés géométriques des différentes représentations sont décrites avec les opérations appliquées aux images. L'extraction d'information de ces visualisations graphiques est donnée par un exemple de comparaison entre un store vénitien classique et un prototype optimisé

Including of specular component in a BTDF or BRDF assessment based on digital imaging

Bi-directional Transmission (or Reflection) Distribution Functions, commonly named BTDFs (and BRDFs), are essential quantities to describe any complex fenestration system in details. They are defined as the ratio of the luminance diffused from a surface element in a given direction (after transmission or reflection), and the illuminance incident on the sample. However, these functions are capable of describing the regular (specular) as well as the diffuse components of emerging light, and their mutual knowledge is necessary to assess a glazing or shading system’s optical performances properly. Although the analytical expression of a BT(R)DF differs whether it is related to regular (specular) or diffuse light, a simultaneous assessment of the two components can be achieved under certain conditions, presented in this paper. They are thereafter analyzed for the particular data acquisition procedure developed for a novel type of bi-directional photogoniometer, based on digital imaging

Identifying and modeling the integrated design process of net Zero Energy buildings

peer reviewedHigh Performance Buildings (HPB), including Net Zero Energy Buildings (NZEBs) and nearly Zero Energy Buildings (nZEB) are emerging as an important market in Europe and around the world. However, there are very few studies that aim to model the process of HPBs and define key design processes, decisions and competencies of design teams. More importantly, there is hardly any documentation processes on tools currently being used to design high performance building. Therefore, the purpose of this paper is to identify, model and propose a generic integrated process maps for HPB. The generic process map focuses on the design phases steps, roles and tools used. The research methodology is based on literature review and a case study. With the help of a process modelling software (TIBCO), a Swiss office building (Green Office) is used to validate the produced process maps. The visual maps delivers insights on the integrated design process reporting on the means of improving the delivery of HPBs

Validation of the performance of a new bidirectional video-goniophotometer

An accurate knowledge of the directional optical properties of advanced fenestration materials is necessary for them to be adequately integrated in buildings. These properties are expressed by the Bidirectional Transmission (or Reflection) Distribution Functions (BTDF, BRDF) of such elements, which are measured by specifically designed measuring equipment: an innovative, time-efficient bidirectional goniophotometer, based on digital imaging techniques, was designed and set up for that purpose. In this paper, the in-depth validation used for the bidirectional measurements performed with this apparatus is presented. It is based on different approaches including experimental error estimation, comparisons to analytical or ray-tracing based models and to other measured data, and calculation of the directional-hemispherical transmittance (reflectance) gauged against measurements of the same systems with Ulbricht (integrating) spheres. The high accuracy and reliability of this novel device were confirmed by this detailed investigation, and led to a maximum error for BT(R)DF data of only 10%

Unweaving the human response in daylighting design

Daylighting as a research topic situates itself at the interface between psycho-physiological and environmental factors, bringing together questions relevant to architectural design and building engineering, but also to human physiology and behavior. While daylighting has a strong impact on human health and well-being, and an undeniable association with (subjective) emotional delight and perceived quality of a space, it is also highly dynamic and variable in nature, based on a combination of predictable (sun course) and stochastic (weather) patterns. This makes it both a challenging and essential aspect of how “performative” a space can be considered. This paper aims to discuss selected research developments regarding how architectural engineering and other domains of science could be more strongly bridged to address the need for meaningful decision support in daylighting design: how can we better integrate the complexity of human needs in buildings into effective design strategies for daylit spaces? As a basis for discussion and to illustrate this overview, it describes a unified goal-based approach in an attempt to address the multiplicity of perspectives from which daylighting performance can – and should – be evaluated in building design. Through five very different perspectives ranging from task-driven illumination or comfort to human-driven health and perception, it proposes a simulation and visualization framework in which one can start approaching these from an integrated approach

Un outil numérique au service de l’éclairage naturel (A simulation tool to support natural lighting)

La protection de l’environnement fait aujourd’hui partie des préoccupations majeures de notre société ; dans ce contexte, la nécessité de réduire la consommation énergétique dans le bâtiment se place comme une priorité. Dans le domaine de l’éclairage, et plus spécialement de la lumière naturelle, des recherches poussées cherchent à optimiser l’utilisation de la lumière du jour pour économiser de l’énergie et mettre à profit ses qualités dans le domaine du confort et du bien-être

LIPID 2013

This document is the 2013 (and first) edition of the yearly activity report of the Interdisciplinary Laboratory of Performance-Integrated Design (LIPID). It introduces the team and their research and teaching activities, as well as their main publications and international collaborations

Dynamism in the context of views out: A literature review

Previous studies have shown that access to a satisfactory view to the outside with sufficient daylight is essential for building occupants\u27 health and well-being. It has also been suggested that certain features of visual content improve view-out quality, such as horizontal stratification, natural landscapes, distant features, and diversity of visual elements. Additionally, having movement and changes in viewing content has been shown to further strengthen building occupants’ engagement and connectivity to their surrounding environment. The objective of this paper is to review the literature on the dynamism of the view content and the inclusion of this criterion in the current metrics of view evaluation. Our review revealed a need for further research on view dynamism, especially focusing on testing different types, speeds, and scales of movement on view quality assessment. It also showed that more comprehensive view evaluation frameworks should be developed to accurately preserve the dynamic qualities of window views in experimental settings. While many view rating metrics have acknowledged the importance of movement, this criterion is to date ignored or only poorly included in existing metrics, which further highlights the need of learning more about this topic

Experiencing a daylit space

To embed the diversity and variability of human needs as foundational elements of daylighting design and put human occupants back at the core of the building question, we need to reach out to fundamental discoveries from neuroscience, biology and other fields, which will bring new insights and a deeper understanding of how we interact with our environment. The multiplicity and variability of our needs regarding (day)light exposure have been a topic of investigation for years now in photobiology and psychophysics, though have not yet penetrated the design realm as dynamic models of human response. Humans need to be in an environment conducive to health and have physiological light exposure needs, whose time- and spectrum-dependent non-visual effects we only start to understand. On the other hand, users of a space often need to perform tasks for which comfortable visual conditions are needed, to which we respond with head and gaze dynamics that psychophysics can help us better recognize. Finally, any attentive witness to a space seeks to enjoy its play of light and dark. Perception of daylight is the primary interpreter of the materiality and dynamism of any architectural space. As a result, while daylight as a subjectively perceived visual effect is actually very hard to use as a design factor, it is often what drives decisions. It is time to bring these exciting new research perspectives back into the design realm in a way it can interactively, dynamically and effectively fuel the creative design process: we have access to the essential ingredients of human-responsive design, now we need to cook