J. of IEIJ Vol.87, No.11

The Abstracts of the Papers
J.Illum. Engng. Inst. Jpn. Vol. 87, 2003

Optimization of the Positioning of Illuminance Meters in a Method that Uses a Database Using by Genetic Algorithm to Locate Light Source
Naoyuki SHIMOMURA, Youhei SHIMADA, Teruyo IMURA and Masayoshi NAGATA

 The ability to locate the position of light sources can be applied to the diagnosis of partial discharges in gas-insulated switchgears (GIS) as an indication of a fault. We propose a method using a database and illuminance meters. In this method, the positions of the illuminance meters affect the accuracy of locating a light source and there are lots of combinations of position of illuminance meters. We describe a method that uses genetic algorithm (GA) to optimize the positions of illuminance meters for locating light sources. A cubic room with six illuminance meters, with each surface having a sensor, is assumed for the optimizing calculation. The accuracy improves from 23.3%, for the configuration with each sensor centered in the surface, to 41.0% for the optimized one. In expanding the detected space to a neighborhood space, the accuracy reaches 92.9%. We also consider optimization of rooms with one or two shading surfaces.

KEYWORDS:detecting light source, genetic algorism(GA), GIS, partial discharge, database, detective precision

On the Simple Prediction Method for Luminance Distribution on Luminous Surfaces of Lit Sign
Akira UCHIDA, Takanori HAMAMOTO, Masahiro MATSUURA and Yoshihiko OHTANI

In the luminance distribution of a lit sign, having no irregularities in brightness is desirable, that is, the uniformity ratio of the luminance should be good. The uniformity ratio is decided by various factors such as the number of lamps, the spacing of the lamps, the distance between the light source and the luminous surface, the inner surface reflectance, and the luminous surface reflectance. A simple prediction method to obtain the relationship between these factors and the uniformity ratio of the luminance was tested by using calculations on a two-dimensional surface. We found that the method was suitable, because the calculated and experimental results agreed with each other.

KEYWORDS:Lit sign, Luminance distribution, Uniformity ratio of luminance

Analysis of Factors Affecting the Lumen Maintenance of Ceramic Metal Halide Lamps
Hisashi HONDA, Akira ITO and Seishi SEKINE

We investigated the factors affecting the lumen maintenance of ceramic metal halide lamps using polycrystalline alumina arc tubes with NaI-TlI-DyI₃ and NaI-DyI₃. As a result, we found that the following phenomena of the arc tubes were the deteriorating factors.
(1) Wall blackening due to deposition of residual carbon within the arc tube.
(2) Deteriorating translucency originating from a formation of a 3Dy₂O₃-5Al₂O₃ garnet, thermal etching of alumina,and abnormal growth of alumina grains.
To prevent the above phenomena,the amount of residual carbon on the tungsten electrodes should be reduced to less than 10ppm and the wall temperature of burning arc tubes should be kept between 950°C and 1050°C.

KEYWORDS:ceramic, metal halide lamp, lumen maintenance, blackening, alumina, carbon

Space Modification Uniform Color-difference in CIELAB Chroma-difference Scale
Hitoshi KOMATSUBARA

An improvement in the CIELAB toward uniformity in color-difference space is presented.Munsell Hue circles at intervals of two Chroma units from Chroma /2 to /20 for Values 9/ to 1/in the CIELAB are not uniform.The basic idea is to modify an equal color difference between the adjacent Munsell Hue lines or Chroma lines.A new chroma-difference scale has been developed that conforms better with the Munsell chroma spacing than the CIELAB does.The center is corrected by mass of the Chroma /2 curves, because of an abnormal displacement of the achromatic point in the Munsell system. The color adaptation effect with illuminance causes the displacement of the achromatic point.

KEYWORDS:uniform color-difference space, CIELAB, color-difference, chroma scale, Munsell system

Evaluation and Analysis of Traditional Town Landscape by Computer Graphics
-Influence on Surrounding Landscape by Vending Machines-
Takashi MIYAGOSHI, Yoshio NAKASHIMA, Mamoru TAKAMATSU and Masayuki IIZUKA

In recent years, it has been viewed that the color of advertising signboards or vending machines on streets should be harmonized with the surrounding landscape.
In this study,we investigated how (red and white)vending machines virtually installed into a scene by using CG would affect a traditional landscape. In addition, we investigated the harmony of the vending machine with the surrounding landscape and compared different cases in which there was advertisements or nothing. Landscape CGs with/without vending machines of Hida-Takayama and Hida-Furukawa were evaluated by 20subjects by using SD techniques. The results of our experiments show that the vending machines have a great influence on the surrounding landscape.On the other hand,we confirmed that they could be harmonized with the landscape if the right colors were used for their paint scheme.

KEYWORDS:landscape evaluation, landscape analysis, computer graphics, vending machines, SD technique