Measuring photometric and spectral radiometric bi-directional transmission and reflection in a video-goniospectrometer

Abstract

The effective use of complex fenestration systems (CFS) in buildings requires a detailed knowledge of their optical spectral and directional properties. Bidirectional scattering functions (BSDFs), either in transmission (BTDFs) or reflection (BRDFs), are used to assess these properties and gather information vital to CFS design and analysis. To enable this analysis in a time and budget conscious manner, an innovative video goniospectrometer, called the Heliodome, has been developed. The Heliodome relies on filtered digital imaging, mathematical methods, and the use of a unique semi-transparent hemispheroidal light collection system to investigate the spectral and angular selectivity of CFS across the visible and near infrared portions of the solar spectrum. This thesis seeks to describe the most recent advancements in the development of the Heliodome-the completion and characterization of the spheroidal mirror component, the integration of a spectral estimation method, the photometric calibration of the camera, and the final automation and validation-- enabling the measurement of both spectral radiometric BSDFs and photometric BSDFs. The completion of this research should support the advancement of CFS that improve the use of daylighting in a space, reducing energy consumption and managing solar gains while improving visual comfort in buildings.