JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 81, Issue 2
Displaying 1-15 of 15 articles from this issue
  • Takayoshi Fuchida
    1997 Volume 81 Issue 2 Pages 73-79
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A new color quantization algorithm is proposed in which skin color data of an image is quantized keeping the original color reproduction as much as possible, while non-skin color data is quantized with the most data reduction.
    This study found that effective image quantization is accomplished with the equidivision procedure of cumulative distribution of image data in L*H*C* space (subspace of L*u*v* space) because the optimal weighting process between high and low frequency data for image data distribution can be achieved. However, using this procedure the color reproduction of an quantized image changes with the occupancy ratio of skin color in the image.
    Subjective discrimination of the difference in color reproduction between a sample image and the original one varies according to the presence or absence of skin color in the image.
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  • Optical Characteristics of One Duct Square Cell of Chromatic Color Louvers
    Masanobu Nishimura, Masaya Wada, Susumu Aiba, Hanji Satone
    1997 Volume 81 Issue 2 Pages 80-88
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    In previous papers the authors described a lighting calculation procedure for a room with an achromatic color louvered ceiling. However, we cannot use this procedure to calculate the luminous colors incident on horizontal illuminated surfaces and the true colors of walls of a room.
    The authors thus started to study the lighting calculation procedure of chromatic color louvered ceiling systems in order to calculate not only illuminance and luminance but also luminous colors incident on horizontal illuminated surfaces and true colors of walls of a room.
    The optical characteristics of chromatic color louvers of one duct square cell, namely, spectral efficiency, spectral changing rate (apparent spectral transmittance), and spectral radiant exitance and chromaticity of light on the undersurface of a louver are important factors for the lighting calculation procedure of chromatic color louvered ceiling systems.
    In this paper, theoretical methods of those characteristics are proposed and their calculated values are given. The calculated values obtained by the theoretical analysis methods on the efficiency and the flux changing rate (apparent transmittance) of louvers and the chromaticity of light on the under surface of a louver are compared with the measured values. It is made clear that this theoretical method is effective.
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  • Influence of the Display Position and the Height of Driver's Eye Position
    Kazumoto Morita, Jinichi Mashiko, Takeo Okada
    1997 Volume 81 Issue 2 Pages 89-95
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The HUD is displayed directly in front of the driver to facilitate quick reading of information. However, because the display image overlaps with the scenery in front, it can be troublesome for the driver. It is thought that the HUD might better be displayed at a position removed from the line of vision extending straight forward.
    We carried out tests in order to determine a display position in which there is no feeling of troublesomeness for the driver. The observers were required to assign one of five levels of troublesomeness to the HUD. The collected data was used to derive the basic relationship between the display position and the feeling of troublesomeness. The influence of the height of the driver's eye position on the feeling of troublesomeness was also analyzed. It is estimated that the drivers with low eye positions would feel much troublesomeness caused by the HUD.
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  • Part 1, Relative Sky Radiance Distribution by Solar Altitude
    Hiroshi Nakamura, Shinya Kojo, Yasuko Koga, Jongho So, Norio Igawa, Ke ...
    1997 Volume 81 Issue 2 Pages 96-106
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The interior environment is heavily influenced by the diffuse irradiance from the sky on the earth surface. This irradiance is often measured, observed, and inspected by research workers and building engineers. The diffuse irradiance is caused by the sky radiance, as well as by the illuminance by daylight brought about by the sky luminance. Both of them originate from solar radiation. Inspection and analysis of solar radiation have been scarcely done until now, though they are absolutely necessary for the precise design of interior environment considering the orientation and inclination of the building surfaces.
    A sky scanner to measure the sky luminance distribution, to which a sensor was attached to measure the sky radiance, was developed for the IDMP. The first remodeled sky scanner has been set up at the IDMP station of Kyushu University, and about 10 remodeled sky scanners have been distributed to IDNIP stations in the world. They are producing an enormous amount of data every day.
    As the first step in the investigation on sky radiance, the relative radiance distribution by solar altitude has been examined by applying the data gathered at the IDMP station of Kyushu University in 1994 and 1995. This paper introduces the relative radiance distribution by solar altitude with a rough explanation on the circumstances of the sky radiance measurement and the remodeled sky scanner.
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  • Masako Miyamoto, Takuko Yanase
    1997 Volume 81 Issue 2 Pages 107-115
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    We studied the effects of color temperature and color rendering of fluorescent lamps as well as chair color on the atmosphere in a living room.
    Four factors-activity, evaluation, softness, gorgeousness were extracted as images of the living room by principal component analysis.
    Color temperature had a strong effect on the atmosphere than color rendering.
    Mutual effects on activity were found between color temperature and chair chroma and between color rendering and chair chroma. Evaluation was affected by relationship between color temperature and chair hue and between color temperature and chair chroma. Evaluation and softness were somewhat affected by color temperature versus color rendering.
    Comfortable illuminance on the desk top was found to be 400-5001x and decreased with increasing color rendering index. Moreover, people tended to regulate it to increase the softness.
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  • Yoshio Watanabe, Jian Yi Lin
    1997 Volume 81 Issue 2 Pages 116-124
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The operating characteristics of the self-excited step-up type inverter for a fluorescent lamp is investigated by simulation using input voltage of rectified 50Hz AC. The envelope curves of voltage and current waveforms of high-frequency oscillation with discharge load are calculated and compared with the measured curves. The obtained results are as follows.(1) Output voltages and currents of the inverter are a function of OFF-time of the switch in the circuit.(2) envelope curves of output voltage and current are proportionally modulated by the input voltage in the case of small input inductance and constant OFF-time.(3) Output envelope curves can be flattened by controlling the OFF-time via the input voltage.
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  • Perfect Color Constancy and Partial Color Constancy
    Ichiro Kuriki, Keiji Uchikawa
    1997 Volume 81 Issue 2 Pages 125-135
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    If a mere apparent color (apparent-color) from an object surface is equal to a color perception as an attribute of the same object surface (surface-color), this condition should be called “perfect color constancy” If not, the condition should be called “partial color constancy.” We looked into the distinction betweeen these two classes of color constancy, while changing illuminant chromaticity around D65. A small room with variable-chromaticity illuminant was used. The walls were painted with N5 gray. A CRT monitor was placed behind an aperture on the front wall, so that the observer perceived the CRT monitor as a reflecting surface on the wall. Observers were asked to make unique-white settings, in terms of both apparent-color and surface-color, under various chromaticites of illuminants. The shift in unique-white represents the shifts in visual sensitivity, and an analysis based on a simple von Kries type model was made. Cone weights for each cone class were defined to represent the state of chromatic adaptation. The change in cone weights show that the sensitivity shift in the visual system follows illuminant chromaticity change only around white, and the visual system was not able to follow illuminant chromaticity-change for saturated illuminants. An additional experiment confirmed that these results had no contamination of simultaneous contrast effect. This result may correspond to the fact that “perfect color constancy” holds under whitish illuminant while “partial color contancy” holds under colored illuminants. In conclusion, we suggest that the “perfect color contancy” can be achieved only by von Kries-like sensitivity change, and the “partial color contancy” requires further processing at the higher stages of the human visual system.
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  • Satoshi Ohyama, Naoki Nakagawa, Nagahiro Saito, Akio Fuwa
    1997 Volume 81 Issue 2 Pages 136-147
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Finite-volume-method computer simulation is used to solve the heat and mass transfer mechanism in small incandescent lamps. For the purpose of more detailed modeling, the HSC method is used to calculate the heat transfer between the inside and outside of the lamp, and the halogen cycle in part of model is used to calculate tungsten mass distribution. Independent of the pressure, the filament temperature, the gas species and the balb radius, the heat conduction governs the radial heat transfer below the Langmuir-film radius, and heat convection develops to govern above it. The pressure increase promotes natural convection.
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  • Toshiaki Mizuno, Hirotaka Hayashi
    1997 Volume 81 Issue 2 Pages 148-153
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    When a metal-halide lamp is operated by a sinusoidal wave of 10k to 100kHz, arc instability caused by acoustic resonance occurs. The frequency regions for stable operation are narrow and vary with the operating condition. Therefore, it is difficult to operate the lamp at high frequency with a fixed frequency.
    This paper presents a ballast for a metal-halide lamp. When the fluctuation of lamp voltage is large because of instability, the operating frequency of the inverter moves back and forth between fmax and fmin, searching for a stable frequency. If the operating frequency coincides with a stable frequency and the lamp voltage fluctuation becomes small, so the operating frequency is maintained. Thus, the lamp operates at some stable point between max and fmin.
    Experiments performed with metal-halide lamp M100·L and stable operation at frequency range of 2025kHz is confirmed.
    This procedure reduces the interference with communication systems compared with square wave operation or frequency modulation.
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  • Dependence of 253.7nm Emission Efficiency on the Discharge Tube Radius in Ar-Hg Mixture Gases (II)
    Yoshio Watanabe, Yoshiichiro Hayashi
    1997 Volume 81 Issue 2 Pages 154-157
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The dependence of 253. 7nm emission efficiency on the discharge tube radius in argon-mercury mixture gases is investigated by simulation for a positive column, using a constant tube wall load. The dependencies of emission efficiency on mercury vapor pressure and argon filling pressure are also investigated. The obtained results are as follows: (1) The emission efficiency has a maximum with the tube radius under constant tube wall load, mercury vapor pressure and argon filling pressure.(2) The emission efficiency has a maximum against mercury vapor pressure, and both the maximum emission efficiency and its optimum mercury vapor pressure increase with decreasing tube radius.(3) Under constant mercury vapor pressure, the emission efficiency at small radii is improved by increasing the argon filling pressure. However, it still decreases with decreasing tube radius due to the increase in elastic loss.
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  • Part 2. Daylit Environment in Office Space
    Hiroshi Nakamura, Injoong Shin, Yasuko Koga, Masaaki Okado, Koichi Got ...
    1997 Volume 81 Issue 2 Pages 158-168
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The goal of this research work is to get an advanced knowledge of the real dynamic state of the luminous environment in the daylit architectural space. For this purpose, measurements have been done in actual architectural spaces, for instance, a house and an office space under various sky and weather conditions. And many useful suggestions have been obtained from the results of analyses of the data gained. This paper reports the results of a study on a daylit environment in office space.
    The following important conclusions were obtained.
    1) Independent of sky and weather conditions, the diurnal fluctuation of the horizontal illuminance, the illumination vector, the scalar illuminance, and the cylindrical illuminance at the same position in a daylit room were similar when no direct sunlight entered the interior. This suggests the possibility of estimating the values and the diurnal fluctuations of the illumination vector, the scalar illuminance, and the cylindrical illuminance in daylit rooms from the horizontal illuminance.
    2) From the viewpoint of modelling and silhouette phenomenon, the quality of the luminous environment of interiors generally deteriorated when the luminous environment of interiors was lit only by daylight.
    3) Generally, the quality of the interior luminous environment could be improved by using supplementary artificial lighting.
    4) There is a danger of excessive amount of artificial light harming modelling conditions.
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  • Yoshikazu Araki, Yasuo Nakagawa, Fumio Ohtani, Tamaki Yaji, Kazuaki Oh ...
    1997 Volume 81 Issue 2 Pages 169-174
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The dependence of the relative spectral responsivity of a thermal radiation detector with a gold-black absorber on thickness of the gold-black layer was studied using models that consider absorption and reflection of incident energy within the absorber. In the models, incident energy is absorbed near the surface and transmitted through the gold-black absorber as heat. The models were formulated, and absorption coefficient and loss coefficient were estimated using the formulation and real data. To get more accurate models, incident energy was assumed to be absorbed gradually within the absorber and transmitted through it from there as heat. The dependence calculated using the models agreed well with real data.
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  • Takeo Yasuda, Hidenori Itou
    1997 Volume 81 Issue 2 Pages 175-179
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Measurements of statistical starting time-lag Ts (s) of non-preheated electronic compact fluorescent lamps show that Ts increases with longer off-time before starting and also in a darker environment on starting. The number of initial electrons per second Q (1/s), which is inversely proportional to Ts, changes from 1.2 to 72 in the dark environment on starting. Initial electrons are mainly obtained from the oxide emitter of the electrodes, even if they are not pre-heated. A brief start requires Q bigger than 260. This is achieved by heating the electrode to only about 100°C.
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  • Part 2, Equation for the Relative Yearly Mean Sky Radiance Distribution
    Hiroshi Nakamura, Shinya Kojo, Yasuko Koga, Jongho Seo, Norio Igawa, K ...
    1997 Volume 81 Issue 2 Pages 180-189
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    A process of composing an equation of sky radiance distribution is shown in this paper. It has been proposed as an equation that expresses the relative yearly mean sky radiance distribution to the zenith radiance. The data gathered at the IDMP station of Kyushu University in 1994 and 1995 were applied. They were carefully inspected many times and refined as the basic data for formulation. After regression analyses were repeated several times, the equation was completed as a function of solar altitude, angular distance from the sun to the sky element and the altitude of the sky element.
    The equation is not so complex. The difference between the basic data and the results obtained by the equation is rather small. This equation is considered to be applicable and useful for practical purposes.
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  • Light: Effects of Background Luminance and Occulting Frequency
    Takashi Irikura, Yoshinori Toyofuku, Yoshiro Aoki
    1997 Volume 81 Issue 2 Pages 191-193
    Published: February 01, 1997
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Download PDF (2189K)
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