Evaluation of Shadows in Sports Lighting -For Watching Sporting
Events on Television-
Kohji KAWAKAMI, Shunsuke KOHKO and Yasuhisa MASUDA
An Electronic Ballast Combined with an HF
Inverter and a Boost Converter Futoshi OKAMOTO and Kenshi SUZUKI
To evaluate how the level of shading on the ground interferes
with the broadcasting of a sporting event on television,
we make clear if the value of the depth of shadow is proper
for an actual depth of shadow, and also it has any influence
to watch on TV. We found that the depth of the shadow
shows that the shading is graded at the same interval
as a sensitivity of human. Therefore, the influence of
the depth of the shadow can be used to evaluate the discomfort
caused by the shadow. For example, if the depth of the
shadow is readjusted to less than 0.5 to the "Just admissible"
level, we will be able to watch TV without any discomfort.
KEYWORDS: sports-lighting, modeling, shadow, TV
Characteristics of Categorical Color Perception
in Peripheral Vision under Low Illuminace
Guidelines for the input current harmonic distortion
of electronic equipment have been established world-wide
to prevent equipment interference through AC main lines.
Electronic ballasts for fluorescent lamps with an inverter
circuit using an active filter circuit have been commercialized.
To simplifily their circuitry the inverter uses a new
technique that combines the inverter with an active filter
circuit. In this paper, an electronic ballast combined
with an HF inverter and a boost converter are reviewed.
The dimming control and stability against a variable load
are examined by using simulation and measurement.
KEYWORDS: electronic ballast, inverter, converter
Kaori SEGAWA and Keiji UCHIKAWA
Basic Performance of VUV Exposure Systems
Using Head-on Type Ar2* and Kr2* DBD Excimer Lamps
We measured the characteristics of categorical color
perception in the peripheral visual field under low illumination
conditions and compared with those under 2000 lx illuminance
in our previous study [J.Illum. Engng. Inst. Jpn. 83 (1999)].
OSA color chips, simulated by the LCD projector, were
presented at the fovea (0 deg), at eccentricities of 30
and 50 deg in the nasal visual field, and at 30, 50, 70,
and 80 deg in the temporal visual field. A large gray
surrounding field, made with a hemisphere, was illuminated
by D65 fluorescent lamps at 5 or 0.1 lx. The stimulus
was subtended 4 deg and presented for 3 s. The observer
reported the color appearance of the stimulus with 1 of
11 basic color terms. The response of color categories
at the fovea showed almost no difference to the 50 deg
temporal under 5 lx illuminance. Beyond the 30 deg nasal
and the 70 deg temporal, the response of achromatic categories
increased, and that of green, purple and pink categories
decreased. Under 0.1 lx the response of achromatic categories
dominated. Our results show that categorical color perception
in the central visual field is constant across a large
visual area under a wide range of illumination conditions.
KEYWORDS: categorical color perception, peripheral visual
field, color vision, basic color
Kenichi HIROSE, Hiroshi SUGAHARA and Hiromitsu MATSUNO
Road Traffic Signal Head with Mask-Film-Type
As an application of dielectric barrier discharge (DBD)
lamps vacuum-ultraviolet (VUV) exposure systems of both
Ar2* and Kr2* excimers have been developed and their basic
performance has been evaluated. Each system comprises
a 20-W DBD excimer lamp, a sinusoidal wave high-voltage
power supply, and a cylindrical lamp holder. A high-voltage
transformer and a lamp are designed to be set as close
together as possible in the holder. The inside of the
holder is purged by nitrogen gas when it is in use. The
excimer lamp has an MgF2 window at the lamp end and is
a "head-on type" lamp.
The head-on type Ar2* excimer VUV system produced monochromatic
light at 127nm (with a 9.8nm FWHM). It's irradiance had
an almost homogeneous distribution within a 15-mm diameter
planar circle at 50? from the output window and was about
The head-on type Kr2* excimer VUV system produced monochromatic
light at 147nm (with a 13.2-nm FWHM). It's irradiance
had an almost homogeneous distribution within a 15-mm
diameter planar circle at 50? from the output window and
was about 1.4mW/ cm2.
The lifetime of the lamps in these system is defined as
the time point at which irradiance drops to 50% of its
initial value. It was 500 and 1500 h, respectively, for
the Ar2* and Kr2* excimer lamps.
KEYWORDS: Ar2* excimer Kr2* excimer, excimer lamp, exposure
system, dielectric barrier discharge, vacuum ultraviolet
Makoto MIYAUCHI, Teuro SHIMOMURA, Masahiro KOUROGI and Naoyuki
Multi-Stage Categorical Color Perception
Revealed with a Color Space Classification Method Kowa
We have developed a road traffic signal head based on
the code for "Phantom prevention type of lamp unit" provided
by the Metropolitan Police Department. The National Police
Agency does not yet have specifications for sun-phantom
prevention-type signal heads, although it is examing such
specifications. The signal head we developed satisfies
the standard for luminous intensity distribution specified
by the National Police Agency, and the shading function
is more effective than previous heads.
KEYWORDS: mask-film, road traffic signal head, luminous
intensity distribution, sun-phantom prevention
KOIDA and Keiji UCHIKAWA
Improved Characteristics of Inductively
Coupled Electrodeless Metal Halide Lamps
We generally express color as some categorical color
even though we have the ability to discriminate millions
of colors. Most studies of categorical color perception
have been based on color naming, so they have been affected
by vocabulary. We have identified the locations of categorical
color perception without the effect of a vocabulary by
using a color space classification method. Five observers
classified a set of 424 OSA color samples and an additional
6 JIS-munsell chips into several (2-14)groups. The locations
of the classified categories were similarly arranged in
color space across the observers. The classified categories
had at least four stages, probably corresponding to multi-stage
categorical color perception. Some classified categories
had regions dissimilar to the categories derived with
a color naming method.
KEYWORDS: color vision, categorical perception, color
Kozo UEMURA, Toshihiko ISHIGAMI, Akira ITO, Ichiro YOKOZEKI,
Keiichi SHIMIZU and Akihiro INOUYE
Methods were investigated to improve the lamp characteristics
of inductively coupled electrodeless metal halide lamps
to make them practical.
First, evaluating lamp efficacy by adjusting the lamp
parameters showed that a lamp efficacy of 180 lm/W with
white color could be attained.
Second, the conditions generating free iodine and bulb
deterioration, the main factors limiting the life of these
lamps, were investigated. For long-life-type lamps, which
had 130 lm/W of lamp efficacy, the lamp lumen level did
not decrease during 21000 hours of overload operation
(corresponding to 58000 hours of rated-load operation).
These lamps thus have excellent lumen maintenance and
life performance compared with conventional electrode
metal halide lamps.
Third, improving circuit reliability by decreasing the
Q value of the resonant circuit was investigated for long-life-type
lamps which had 145 lm/W of lamp efficacy. The relationship
between the Q value and the lamp parameters was analyzed,
and the Q value was decreased to 78% its value while maintaining
the same lamp performance.
KEYWORDS: electrodeless metal halide lamp, free iodine,
long life, lumen maintenance