This research demonstrates the use of High Dynamic Range (HDR) fisheye images of the sky dome in lighting simulations. The objective is to improve the
accuracy of simulations with site specific sky conditions. The luminance information stored at a pixel level in an HDR photograph is used to light the
simulated environment through an Image Based Rendering (IBR) technique. The results show that image based sky models can provide a more accurate
and efficient method for defining the sky luminance distributions and the impact of surrounding urban fabric and vegetation as compared to generic CIE sky models and explicit modeling of surrounding urban fabric and forestry.
PUBLICATIONS:
-
Inanici M. “Evaluation of High Dynamic Range Image-based Sky Models in Lighting Simulation,” Luekos, Journal of the Illuminating Engineering Society (IES), 7(2), October 2010, 69-84. [pre-print version]
-
Inanici MN. “Applications of Image based Rendering in Lighting Simulation: Development and Validation of Image based Sky Models”, Proceedings of the 11th International Building Performance Simulation Association (IBPSA) Conference, July 27-30, 2009, Glasgow, UK.
ACKNOWLEDGEMENT:
This work was funded by the University of Washington Royalty Research Fund (2009-2010).
DATA:
HDR sky images were captured for one day in every month between December to June (winter solstice to summer solstice) at 15 minute intervals during daylight hours. The database includes images from December 28, 2009 (32 image sets), Jan 31, 2010 (38 image sets), Feb. 20, 2010 (43 image sets), March 27, 2010 (49 image sets), April 25, 2010 (48 sets), May 23 (43 image sets), and June 22 (53 image sets). The dates were chosen around the 21st of each month. Dates vary to allow capturing varying weather conditions and to avoid inclement weather (to prevent equipment damage). The database covers a wide range of possible sun angles and sky conditions for Seattle. Sample HDR images from January under overcast sky and June under partly cloudy sky taken at noon are available here. Images © Inanici, 2011.
EVALUATION OF HIGH DYNAMIC RANGE
PHOTOGRAPHY
AS A LUMINANCE MAPPING TECHNIQUE
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.
PUBLICATIONS:
-
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.
APPLICATIONS:
ACKNOWLEDGEMENT:
This work was funded by the Assistant Secretary for Energy Efficiency and
Renewable Energy, Office of Building Technology, Building Technologies Program of
the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.
LUMINANCE DISTRIBUTION PATTERNS AND GLARE
-
Van den Wymelenberg K, Inanici M and Johnson P. “The Effect of Luminance Distribution Patterns on Occupant Preference in a Daylit Office Environment,” Luekos, Journal of the Illuminating Engineering Society (IES), 7(2), October 2010, 103-122. [pre-print version]
-
Van den Wymelenberg K and Inanici M. “A Study of Luminance Distribution Patterns and Occupant Preferences in Daylit Offices,” Proceedings of the Passive and Low Energy Architecture (PLEA) 2009 Conference, Quebec City, Canada, June 22-24, 2009.
| PHYSICALLY BASED RENDERING AND PER-PIXEL LIGHTING ANALYSIS: |
NEW METRIC FOR QUANTIFYING THE DIRECTIONALITY OF LIGHT:
DIRECTIONAL - TO - DIFFUSE RATIO
 |
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. |
PUBLICATION:
PER-PIXEL LIGHTING DATA ANALYSIS
PUBLICATIONS:
VIRTUAL LIGHTING LABORATORY
Virtual
Lighting Laboratory (VLL) is an advanced lighting analysis tool and
methodology
that is based on post-processing of the physically-based
renderings. It enhances the integration
of the lighting analysis
into the
architectural design process through computational tools that make the
analysis
more convenient, accessible, accurate, and rigorous. The research
includes the
theory, implementation, and application of the virtual meters
(luminance meter,
illuminance meter, contrast meter, integrating sphere, and colorimeter)
as well as the development of unique analysis options and metrics that
are pertinent to the computational per-pixel data.
PUBLICATIONS:
-
Inanici MN and Navvab M. "The Virtual Lighting Laboratory: Per-pixel Luminance Data Analysis", Luekos - Journal of the Illuminating Engineering Society of North America, 3(2), October 2006, pp. 80-104.
-
Inanici
MN. Transformations in Architectural
Lighting Analysis: Virtual
Lighting Laboratory. Dissertation: The University of Michigan, College of Architecture and Urban Planning, 2004. Available from: ProQuest Information and Learning,
Ann Arbor
,
MI
; AAT 3121949.
-
Inanici
MN. "Transformations of High Dynamic Range Images into Virtual Lighting
Laboratories". International Building Performance and Simulation Association (IBPSA) 2003 Conference, Eindhoven, Netherlands,
10-14
August, 2003.
-
Inanici MN. "Utilization of Image Technology in Virtual Lighting Laboratory". International
Commission on Illumination (CIE) 2003 Conference, San Diego, 26-28 June, 2003.
-
Inanici M. “Application of the state-of-the-art Computer Simulation and Visualization in Architectural Lighting Research," Proceedings of the 7th International Building Performance and Simulation Association (IBPSA) 2001 Conference, Rio de Janerio, Brazil, August 13-15, 2001.
| PERCEPTUALLY BASED LIGHTING SIMULATION: |
PUBLICATIONS:
Tai NC and Inanici M. “Space Perception and Luminance Contrast: Investigation and Design Applications through Perceptually based Simulations,” Spring Simulation Multi-conference, Symposium on Simulation for Architecture and Urban Design (SimAUD2010), Orlando, FL, April 12-15, 2010.
-
Tai NC and Inanici M. “Lighting in Real and Pictorial Spaces: A Computational Framework to Investigate the Scene based Lighting Distributions and their Impact on Depth Perception,” Association of Computer Aided Design and Research in Asia (CAADRIA) 2010 Conference, Hong Kong, April 7-10, 2010.
-
Tai NC and Inanici M. “Depth perception as a function of Lighting, Time, and Spatiality,” Short paper, Illuminating Engineering Society (IES) 2009 Conference, Seattle, WA, November 16-18, 2009.
-
Tai NC and Inanici M. “Depth Perception in Real and Pictorial Spaces: A Computational Framework to Represent and Simulate the Built Environment,” Proceedings of the Association of Computer Aided Design and Research in Asia (CAADRIA) 2009 Conference, Yunlin, Taiwan, April 22-25, 2009.
| ENERGY EFFICIENT BUILDING DESIGN: |
PUBLICATIONS:
-
Demirbilek N, Yalciner U, Ecevit A, Sahmali E, and Inanici M. “Analysis of the Thermal Performance of a Building Design located at 2465m: Antalya - Saklikent National Observatory Guesthouse,” Building and Environment, 38(1), Jan 2003, pp. 177-184.
-
Inanici M and Demirbilek N. “Thermal Performance Optimization of Building Aspect Ratio and South Window Size in Five Cities having Different Climatic Characteristics of Turkey,” Building and Environment, 35(1), Jan 2000, pp. 41-52.
-
Demirbilek N, Yalciner U, Inanici M, Ecevit A, and Demirbilek O. “Energy Conscious Dwelling Design for Ankara,” Building and Environment, 35(1), Jan 2000, pp. 33-40.
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Demirbilek N, Sahmali E, and Inanici M. “A Passively Climatized Building, 2500 m Above Sea Level,” Proceedings of Solar'97 - Australian and New Zealand Solar Energy Society, Canberra, Australia, paper 56, Dec. 1-3, 1997.
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© Mehlika Inanici
Last update: October 2010
