JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN
Online ISSN : 1349-838X
Print ISSN : 0019-2341
ISSN-L : 0019-2341
Volume 67, Issue 10
Displaying 1-9 of 9 articles from this issue
  • Yoshihiro Ohno, Osamu Yamada, Shuji Tamaru, Jun-ichi Hatayama, Tetsuo ...
    1983 Volume 67 Issue 10 Pages 485-490
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    In the past, in order to measure photometric characteristics of road and/or tunnel lighting inst allations, the so-called mobile laboratory has been used. For the mobile laboratory, however, to eliminate shadows of the vehicle over the photocells as much as possible, a long trailer, i. e. a long frame construction carried by two wheels, with a length of about 4 meters on which the photocells were mounted, was necessary. As a consequence, the driving speed of the mobile laboratory, consisting of a vehicle and a trailer, was limited to a relatively low level. This necessitated a strict control of the traffic on the road when the measurements were carried out. Based on a previous idea by J. Green et. al., an attempt was made to develop a measuring system by utilizing a number of pairs of two photocells in combination with an electronic data processing unit, one each in the front and another in the rear of the vehicle (instead of pulling a long trailer) with which the illuminance in the front hemisphere and in the rear hemisphere, respectively, were measured independently and supplementally with each other.
    In this paper, firstly, the spatial and dynamic response of the pairs of photocells are analyzed in relation to their geometric construction, driving speed, and the mounting height of the luminaires. Secondly, requirements for the photometric performance of the pair of photocells in conjunction with performance of the data processing unit are discussed. Thirdly, componential error factors are examined separately as well as accumulatively. Finally, the performance of the spatial filter incorporated in the system, with which signals as to the driving speed can remotely be obtained, is described.
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  • Mitsuo Ikeda, Yoshiaki Nagata, Hirohisa Yaguchi, Shoko Ashizawa
    1983 Volume 67 Issue 10 Pages 491-496
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Change of spectral luminous efficiencies for brightness was investigated under the daylight where the illuminance varied from about 3, 000 lx down to 0.1 lx in the time course of evening of February. The experimental method was to match the brightness of test stimuli of blue and orange colored papers with a gray scale and to express the brightness by the equivalent value of the gray scale, VB or VOR, respectively. The lightness remained about the same until 17: 25 hrs, when a change started such that VB increased and VOR decreased to indicate the beginning of the mesopic vision. The change ceased at around 17: 55 hrs by giving the increased amount of VB of about 1 and the decreased amount of VOR of about 2.5. The illuminance was about 10 lx when the mesopic vision started. Such mesopic vision never started at the down area where artificial illuminations were abundant.
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  • Naoyoshi Nameda
    1983 Volume 67 Issue 10 Pages 497-502
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Lamps that include optical systems, such as reflector lamps, often show uneven light distribution.
    This light distribution unevenness can be prevented by adding a slight diffusing function to the reflector or its window. However, even if, two samples appear to have same outward diffusing grade, for example chemically etched frosted glass and white powder coated glass, they often show absolutely different light distribution.
    Therefore, it is necessary to measure and control the diffusion optical characteristics.
    An easy method to measure the diffused light distribution grade was investigated.
    The light distribution caused by light refracted from, or reflected by chemicallyetched frosted glass lit by a parallel beam was found to be similar to Gauss distribution.
    One method of calculating the diffused light distribution is to place another diffusing glass plate into the diffused light field from the light source.
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  • Shoko Ashizawa, Mitsuo Ikeda
    1983 Volume 67 Issue 10 Pages 503-508
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Brightness of 16 different clothes was investigated under various illumination levels covering 1000 to 0.01 lx. A gray scale made of 15 steps of lightness was used to evaluate the brightness. Red clothes lost their brightness gradually as the illuminance level decreased, while the most of the blue ones slightly gained their brightness when the level became extremely low. A blue cl oth of very small brightness, however, lost its brightness for less illuminance on the contrary to the commonly accepted phenomenon of the Purkinje shift. A yellow cloth did not show any change in its brightness. These characteristics of brightness change did not depend on the materials, but only on the colors of clothes. The starting point of mesopic vision was estimated from the present results as about 3 lx.
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  • Minoru Isomura, Motomi Yamauchi
    1983 Volume 67 Issue 10 Pages 509-513
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Illuminance and luminance distributions in rooms are strongly influenced by the reflectance characteristics of the surfaces.
    The goniophotometric properties of many practical surfaces can be considered as exhibit both a diffuse and a specular component of reflectance.
    The reflectance of the mixed diffuse-specular surface is apparently influence by the angle of incidence of the light.
    This paper describes an approximate calculation method of interreflections it rooms with the mixed diffuse-specular surfaces considering the effect of the angle of incidence of the light.
    The approximation is based on the assumption that mixed diffuse-specular surfaces can be treated solely as uniform diffusers for all interreflections.
    Calculated values of the luminous exitance of the floor surface by this method are compared with mesured values and showed the effect of specular and diffuse wall reflectance components on the average illuminance of the floor surface is shown.
    The results show that significant errors occur if the reflectance of the mixed diffuse-specular surfaces is treated to be unaffected by the angle of incidence of the light.
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  • Yasuo Nakagawa, Fumio Ohtani
    1983 Volume 67 Issue 10 Pages 514-519
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The measurements of sensitivity chracteristics of several radiation detectors (silicon photodiodes and photo tubes) were carried out. The relative spectral sensitivity in the wavelength region of 190 to 780 nm was calibrated by a monochromator with about 6. 7 nm bandwidth and a gold black coated PVF2 pyroelectric radiation detector. The absolute sensitivity was calibrated with a ETL spectral irradiance standard lamp and broad bandpass filters. Several times measurements were carried out through about three years and the sensitivity change in sample was also examined.
    The results of measurements are as follows:
    (1) The sensitivity of silicon photodiodes at 190 nm is 0.15 to 0.28 times of 560 nm value.
    (2) In all silicon photodiodes, the sensitivity decrease is observed near the wavelength of 365nm, 275mm and 210nm. These correspond to bands gap absorption of silicon single crystal.
    (3) In the wavelength region of 550 to 760 nm, the relative spectral sensitivity of HTV 1337 type silicon photodiodes is agreed with the constant quantum yield radiation detector within ±1% deviation.
    (4) The change in sensitivity of four silicon photodiodes for 1 to 3 years is 1 to 1.5% in whole wavelength region.
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  • Yoshinobu Nayatani, Kenjiro Hashimoto, Kotaro Takahama, Hiroaki Sobaga ...
    1983 Volume 67 Issue 10 Pages 520-526
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    Studies on observer metamerism reported so far are classified into two groups; one is studied by G. Wyszecki, E. Allen, and Y. Nayatani et al based on the Stiles's 20 color-matching functions, and the other by P. K. Kaiser et al and F. W. Billmeyer et al on the basis of color-matching assessments on the Davidson and Hemmendinger color rule. It has been suggested that a large difference exists between the two series of studies on a ratio of observer metamerism index to illuminant metamerism index. This difference is analyzed by using the Stiles's 20 color-matching functions and the color-rule samples.
    The results are; (1) the ratio of age effect on observer metamerism to illuminant metamerism index estimated by the Stiles's 20 observers are very similar to that given by P.K. Kaiser et al., (2) the large difference between the two study series stated above is partly caused by the computational procedure used for deriving each observer-metamerism index, and (3) the Stiles's 20 observers are a good representative of color-normal observers covering a wide range of age from ahniit 20 to about 60.
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  • Koichi Ikeda, Koji Noda, Shoichiro Yamaguchi
    1983 Volume 67 Issue 10 Pages 527-533
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The purpose of this study is to investigate the visual acuity as a function of the luminance contrast of the test objects and the adaptation lminance. The test objects are Landolt rings with the luminance contrast from 3 to 92%. The observers, all with normal vision, judge the break orientations of the Landolt rings by guessing. Visual experiments are carried out according to the standard method of the visual acuity test. Results obtained are as follows.
    (1) The resolvable visual angle θ can be expressed as a function of the lum nance contrast C (%) and the adaptation uminance L (cd/m2),
    θ=1.6293C-0.3234 (0.8034C-0.1876+L1/4) 4/L (minutes)
    For practical use, following equation is derived as a simple and convenient formula to calculate the resolvable visual angle.
    θ=1.7C-1/3 (0.85C-1/5+L1/4) 4/L(minutes)
    (2) As the luminance contrast of the test objects can not be discriminated below a certain adaptation luminance, the visual acuity is not defined and the above equations do not hold below this luminance. This threshold luminance is expressed as a function of the luminance contrast; i. e.,
    L=2.974C-1.7234 (cd/m2)
    (3) The visual acuity in the vertical and the horizontal directions are slightly higher than those in the oblique onse irrespective of the luminance contrast of the Landolt rings.
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  • Kyosuke Furukawa, Masumi Ishikawa, Toshio Yamanaka, Motoi Nanjo, Yutak ...
    1983 Volume 67 Issue 10 Pages 534-539
    Published: October 01, 1983
    Released on J-STAGE: July 19, 2011
    JOURNAL FREE ACCESS
    The present paper deals with estimation of various errors for measuring retroreflective materials used for traffic signs, and establishment of their standard. The effect of illuminance distribution on CIL (coefficient of luminous intensity) values was reduced by adopting the average value of illuminance at nine points on the sample surface.
    For determination of CIL values, a correction was taken, for slight deviation of spectral sensitivity of the photometer head from spectral luminouss efficiency V (λ), by using a correcting factor calculated from the measurements of spectral reflectance of samples and spectral sensitivity of the photometer head. The errors of sample setting were estimated as 0.3 to-0.1 degrees of arc, and the standard deviation of the CIL value of samples as 0.5 to 0.6%.
    Two of the samples took an interlaboratory test among six laboratories for checking industrial standards.
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