|Title||Multi-point simultaneous illuminance measurement with high dynamic range photography|
|Publication Type||Conference Proceedings|
|Year of Conference||2013|
|Editor||Grobe LO, Wittkopf SK|
|Number of Volumes||2|
|Publisher||Solar Energy and Building Physics Laboratory (LESO - PB) Ecole Polytechnique Fédérale de Lausanne (EPFL)|
|Keywords||daylight, goniophotometry, high dynamic range imaging, illuminance, Lambertian diffuser|
Daylight illuminance uniformity is a common criterion when assessing the performance of fenestration and solar control. To evaluate a design according to this requirement, a grid of horizontal illuminance readings for a given time is required. In simulation based assessments, this can be calculated by defining sensor points at working plane level and running a simulation for a single time step, or an annual simulation to assess the uniformity for a typical year. Backing such predicted assessments with measured data has been a task involving installation and calibration of sensors, cabling and data acquisition systems, which typically render the assessed space unusable for the time of assessment. Using sequential readings from handheld devices as a convenient alternative ignores the dynamics of daylight, as the sky conditions cannot be assumed constant during the time required to record the illuminance at the required amount of locations.