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Volume 82, Issue 11
Displaying 1-8 of 8 articles from this issue
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Shigeo Ohagi, Yoshihiko Hazama, Takeshi Nishimura1998 Volume 82 Issue 11 Pages 859-868
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSIn a previous paper, we carried out a subjective evaluation by paired comparison to examine the contribution of three color attributes to “Fukami”, and then to form the “Fukami” scale. We found that “Fukami” is related to the decrease in value and chroma, and also that it depends on the difference in hue. After the evaluation, it was reported that “Fukami” was depended on the degree of color depth sensation. We took notice of this fact.
First, we studied the relationship between “Fukami” and the color depth sensation. For both sensations, there were many similar tendencies for the change in value and the difference in hue. But for low values and chromatic color areas, the contribution of the chroma to each sensation was opposite, therefore we could not find a good relation between them.
Next, we defined the “Kuromi” sensation based on the color depth sensation and examined the relation to “Fukami”. We verified that the “Kuromi” (KL*) increased with the increase in color depth sensation and the decrease in chroma. The fundamental relation model between“Fukami” and “ Kuromi” is described as follows.
Fukami=Kh (KL*-δh) [δh≤KL*≤10]
Kh and δh are calculated from the hue (dH5p). This equation is very simple and explicates the effect of “Kuromi” in relation to “Fukami”. But, the equation has the tendency to shift the “Fukami” peak from hue GY to hue BG, of equal value, with the decrease in chroma. So, we consider it necessary to improve the equation for practical use.View full abstractDownload PDF (2739K) -
Naotaka Ikemoto, Minoru Isomura1998 Volume 82 Issue 11 Pages 869-876
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSWe propose an approximate method of calculating the working plane illuminance in a room containing fixtures. This method requires only one-eighth as many calculated form factors as conventional methods, takes little time, and can use a small memory. However, it must calculate a great many view functions which are determined by the ability of the centre or some part of the arbitary element to‘see’ the centre of other elements. This paper describes the effect of room fixtures on the floor illuminance distribution in a room with a louvered light source having either a narrow or wide angle. The results show that it does not depend on the luminous intensity distribution of light source. It also proposes a simple method of predicting the floor illuminance distribution in such a room and presents results that agree well with the approximately calculated ones.View full abstractDownload PDF (3223K) -
Keiko Endoh, Kohji Matsue, Shu Takeshita, Toshibumi Sakata, Masako Sas ...1998 Volume 82 Issue 11 Pages 877-883
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSUltraviolet radiation can cause photochemical and photobiological damage in plants, animals, and humans. As a consequence of ozone depletion, an increase in solar ultraviolet radiation is expected in outdoor environments. However, there is very little quantitative data on it. We measured solar ultraviolet-B and ultraviolet-A irradiances in typical outdoor environments (concrete, grass, sand, soil, and snow) at a height of 150cm (the average height of a Japanese adult's face) at various local standard times with solar elevations ranging from about 30° to 75° from the horizon. In each environment, measurements were taken for six directions relative to the sun: direct, overhead, front, side, back, and downward. Solar UV-B and UV-A irradiances in four of the outdoor environments (concrete, grass, sand, and soil) showed similar distribution patterns in each of the six directions, although snow gave extremely large reflection. In addition, solar UV-B and UV-A irradiances were measured in and near the shade of a tree, and on a person's cap or hat. In all cases, we found that solar elevation and direction to the sun are major factors in protection from solar ultraviolet radiation.View full abstractDownload PDF (7262K) -
Takashi Fukue, Kazurou Harada, Yoshiyuki Ishihara, Toshiyuki Todaka, F ...1998 Volume 82 Issue 11 Pages 885-893
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSThis paper presents a novel dimming circuit using intermittent oscillation in the self-excited electronic ballast for an electrodeless fluorescent lamp. A resonant half-bridge inverter with zero-voltage-switching is used for the electronic ballast. This self-excited electronic ballast satisfies technical conditions for intermittent oscillation. These conditions have been investigated by using separately-excited electronic ballast. Derived conditions are as follows. 1) Coil voltage must be over 600V at no-load to achieve a short enough striking time compared with the period (several milliseconds) of the dimming signal. 2) A fast-response control circuit is needed to achieve a short enough delay time at starting and stopping compared with the period of the dimming signal. Previous starting circuits using a voltage-breakover-type device (DIAC, Zener diode etc.) are not suitable for intermittent oscillation because the delay time is too longer. Our dimming circuit consists of an auxiliary switch for intermittent oscillation and the starting circuit consists of only resistance and capacitance. In an experiment at 2.65MHz, our circuit had a sufficiently short delay time below 100μs and controlled the illuminance of the electrodeless fluorescent lamp from 100% to under 5%.View full abstractDownload PDF (1583K) -
Tadashi Yano, Kenjiro Hashimoto1998 Volume 82 Issue 11 Pages 895-901
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSA woman's complexion color is an important and familiar factor in the evaluation of preferred color appearances under illumination. For this reason, a new method of estimating preference for Japanese complexion color under illumination is proposed in the present study. To clarify the relationship between preference for Japanese woman complexion under illumination and the chromaticity coordinates of the complexion on the CIE 1976 u' v' chromaticity diagram, we analyzed subjective evaluation data obtained by evaluating the color appearance of 40 complexions by using seven evaluation categories in detail. A new preference index PS for Japanese complexion color under illumination was derived from the experimental results. It was clarified that the new index PS correlated well with not only the experimental data but also with preference for Japanese woman complexion color under illumination produced by various kinds of light sources adopted. The new index PS can evaluate the preferences concerning Japanese woman complexion color related to light sources better than the standard illuminant D65, which can not be evaluated by the present index Ra proposed by CIE and JIS. The preference index for the complexion color PS proposed in the present study will be useful related to a practical estimation index of the color rendering properties of light sources from the viewpoint of preference of complexion color.View full abstractDownload PDF (2066K) -
Hiroaki Sobagaki, Kotaro Takahama1998 Volume 82 Issue 11 Pages 902-915
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSIn the previous study (Sobagaki et al., 1983), we applied principal component analysis to the measured spectral reflectance distributions (SRDs) of the JIS Z 8721 color chips, and proposed a reconstitution method for deriving the SRD corresponding to any specified Munsell renotation. However, the SRD generated by the method did not satisfy the object color condition (0≤ρ (λ) ≤1) for highly saturated colors, where ρ (λ) denotes to the SRD.
In this paper, we derive the SRD satisfying the object color condition in the region of highly saturated colors. The SRD of highly saturated colors is given by combining the SRD obtained by the reconstitution method with that of optimal colors and with those of achromatic colors. This method was applied to all the highly saturated colors specified in JIS Z 8721 to provide the standard colorimetric values under CIE standard illuminant D65.View full abstractDownload PDF (2456K) -
Makoto Miyauchi, Teruo Shimomura, Masahiro Kourogi, Naoyuki Shintou1998 Volume 82 Issue 11 Pages 917-920
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSDownload PDF (2031K) -
Wataru Iwai1998 Volume 82 Issue 11 Pages 921-925
Published: November 01, 1998
Released on J-STAGE: July 19, 2011
JOURNAL FREE ACCESSDownload PDF (3910K)
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