Coralie Cauwerts

Application of High-Dynamic Range Imaging Techniques in Architecture: A Step toward High-Quality Daylit Interiors?

High dynamic range (HDR) imaging techniques are nowadays widely used in building research to capture luminances in the occupant field of view and investigate visual discomfort. This photographic technique also makes it possible to map sky luminances. Such images can be used for illuminating virtual scenes; the technique is called image-based lighting (IBL). This paper presents a work investigating IBL in a lighting quality research context for accelerating the development of appearance-driven performance indicators. Simulations were carried out using Radiance software. The ability of IBL to accurately predict indoor luminances is discussed by comparison with luminances from HDR photographs and luminances predicted by simulation in modeling the sky in several other more traditional ways. The present study confirms previous observations that IBL leads to similar luminance values than far less laborious simulations in which the sky is modeled based on outdoor illuminance measurements. IBL and these last methods minimize differences with HDR photographs in comparison to sky modeling not based on outdoor measurements.

Definition of the CIE standard skies and application of high dynamic range imaging technique to characterize the spatial distribution of daylight in Chile

The effectiveness and accuracy of a daylight lighting study relies on knowing the climate and light conditions available at a given place, to then evaluate the illuminance obtained during the project process. This paper presents the methodologies of a research process carried out, whose objective is providing realistic data to provide the foundations for future lighting studies in Chile. It starts with the revision of the metrics to quantify daylight; later, the methodology used to collate the frequency information month-on-month on four types of standard CIE skies, starting from climate files, is presented. Finally, the methodology and the results obtained are shown to measure and characterize the real skies, the High Dynamic Range photographs (HDR) and as complement of this information, the illuminance measurements of the sky dome to define the types of skies of six Chilean cities. From the study applied, it is possible to conclude that knowing the standard CIE skies of a place allows us to adjust and focus the daylighting study for predetermined and predominant skies. It is just as important to mention that the measuring techniques for the skies must be adjusted and calibrated for each studied location.