• Architectural Lighting
• Building Performance Simulation
• Computer Graphics (Physically Based Rendering)
• Computational Photography (High Dynamic Range Photography)
• Energy Efficient Buildings
  

Directionality of light is the balance between the diffuse and directional components within an environment. It has a significant impact on the appearance of 3D objects; and the visual performance and comfort of occupants within that environment. Poor directionality may produce harsh shadows on the task, cause veiling reflections towards the viewing angle, or create a dull environment. Adequate directionality may model 3D surfaces, reveal the surface textures or details of a task, and create an aesthetically pleasing environment. A new metric is derived from the basic definition of directionality: The diffuse and directional components of the luminous environment are isolated as a unique feature of simulation-based approach and the ratio of the directional-to-diffuse light is calculated. The rationale and methodology of the directional-to-diffuse ratio is discussed through visual demonstrations and quantified metrics.

•  Inanici MN. “Computational Approach for Determining the Directionality of Light: Directional-to-Diffuse Ratio”, Proceedings of the 10th International Building Performance Simulation Association (IBPSA) Conference, September 3-6, 2007, Beijing, China, pp. 1182-1188.
  

   

The potential, limitations, and applicability of the High Dynamic Range (HDR) photography technique is evaluated as a luminance mapping tool. Multiple exposure photographs of static scenes are taken with a  digital camera to capture the wide luminance variation within the scenes. The camera response function is computationally derived using the Photosphere software, and is used to fuse the multiple photographs into HDR images. The vignetting effect and point spread function of the camera and lens system is determined. Laboratory and field studies have shown that the pixel values in the HDR photographs can correspond to the physical quantity of luminance with reasonable precision and repeatability.

•  Inanici MN. “Evaluation of High Dynamic Range Photography as a Luminance Measurement Technique”, Journal of Lighting Research and Technology, Vol. 38, no. 2, June 2006, pp. 123-136.
  
•  Inanici MN. “Per-pixel Data Acquisition with High Dynamic Range Photography” International Commission on Illumination (CIE) 2005 Conference, Leon, Spain, 18-20 May, 2005.
• Inanici MN and Galvin J. Evaluation of High Dynamic Range Photography as a Luminance Mapping Technique. Lawrence Berkeley National Laboratory, LBNL Report # 57545, 2004. Available from: University of California eScholarship Repository and LBNL Library.

     Daylighting the New York Times Headquarters Building

                                    Low Glare Outdoor Luminaire 
                                    California Energy Commission’s Public Interest Energy Research (PIER) Buildings Program