DocumentCode :
986659
Title :
Uniform Illumination Rendering Using an Array of LEDs: A Signal Processing Perspective
Author :
Yang, Hongming ; Bergmans, Jan W M ; Schenk, Tim C W ; Linnartz, Jean-Paul M G ; Rietman, Ronald
Author_Institution :
Dept. of Electr. Eng., Eindhoven Univ. of Technol., Eindhoven
Volume :
57
Issue :
3
fYear :
2009
fDate :
3/1/2009 12:00:00 AM
Firstpage :
1044
Lastpage :
1057
Abstract :
An array of a large number of LEDs will be widely used in future indoor illumination systems. In this paper, we investigate the problem of rendering uniform illumination by a regular LED array on the ceiling of a room. We first present two general results on the scaling property of the basic illumination pattern, i.e., the light pattern of a single LED, and the setting of LED illumination levels, respectively. Thereafter, we propose to use the relative mean squared error as the cost function to measure the uniformity of the realized illumination pattern, and provide an analysis for this cost function. Based on the analysis, the design of a basic illumination pattern is discussed. The performances of a few basic illumination patterns are compared, and an approach for optimizing the basic illumination pattern through a weighted combination of these basic patterns is also proposed. A weighted combination of Gaussian and raised-cosine functions is found to yield the best results. Finally, three basic regular grid shapes for an LED array are compared. The results show that 13% and 39% of LEDs can be saved for the same degree of uniformity, using the hexagonal instead of the rectangular and triangular grid, respectively.
Keywords :
Gaussian processes; light emitting diodes; signal processing; Gaussian function; LED array; indoor illumination systems; light-emitting diodes; raised-cosine functions; rectangular grid; signal processing perspective; triangular grid; Basic illumination pattern; LED illumination; regular grid; two-dimensional signal processing;
fLanguage :
English
Journal_Title :
Signal Processing, IEEE Transactions on
Publisher :
ieee
ISSN :
1053-587X
Type :
jour
DOI :
10.1109/TSP.2008.2009269
Filename :
4671093
Link To Document :
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