All issues
Volume 4 (1980)
- Issue 2 Pages 2_1-
- Issue 1 Pages 1_1-
Volume 4, Issue 2
Displaying 1-6 of 6 articles from this issue
- |<
- <
- 1
- >
- >|
-
Toshihiko ISHIGAMI, Hiroki SASAKI, Satoshi NAGANO, Tadatoshi HIGASHI1980 Volume 4 Issue 2 Pages 2_1-2_7
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSControlling two factors on which Sc-Na halide lamps depend, the coldest spot temperature in the arc tube and the Nal to Scl3 weight ratio contained in the arc tube, the radiation power of 400 W Sc-Na halide lamps was quantitatively measured by spectro-radiometer. The experimental temperature range was 500∼800°C and the Nal to Scl3 filling weight ratio was 1,2,5 and 7. Spectral characteristics (chromaticity, correlated color temperature, general color rendering index), visible radiation, luminous flux and radiation from Sc, Na and Hg particles, in four kinds of lamps were compared, based on measured radiation data and determining the coldest spot temperature for a lamp with outer jacket by means of measuring lamp voltage change. As a result, the data for considering Sc-Na halide lamps characteristics were get. The Sc radiation became larger as the Nal weight ratio became smaller. There was constant saturation value in the Sc radiation. The change in visible radiation, luminous flux, lamp voltage and general color rendering index for four kinds of Sc-Na halide lamps was coincident with the change in Sc radiation.View full abstractDownload PDF (642K) -
Ryo SUZUKI, Michihiro TSUCHIHASHI, Katsuya OTANI, Keiji WATANABE1980 Volume 4 Issue 2 Pages 2_8-2_13
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSA retrofit high pressure sodium lamp initiates discharge with the aid of surge voltage generated in a choke ballast at the moment of operation of Bl-metallic switch. The large dispersion of the surge voltage has been imposing restriction on operation of the lamp on the mercury lamp ballast so as to avoid destruction of insulation of operating circuits. The dispersion and the value of the surge voltage could be decreased by introducting gas into an outer bulb. It is this reason that the surge voltage could not go over a certain value, because the conductivity of the gas would be increased by the discharge when the generated voltage exceeded a certain value. The authors applied this new method to a practical retrofit HPS lamp and confirmed that the dispersion and the value of the surge voltage could be decreased without any sacrifice on the starting and other performance of the lamp.View full abstractDownload PDF (570K) -
Hirohisa YAGUCHI, Mitsuo IKEDA1980 Volume 4 Issue 2 Pages 2_14-2_17
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSThe present photopic photometric system is based on the CIE photopic relative luminous efficiency function V(λ), most of whose data were obtained by the flicker photometry. In recent years, however, it is pointed out that the CIE V(λ) does not necessarily represent the spectral sensitivity for the brightness perception. In the present experiment, the relative luminous efficiency functions were determined by the heterochromatic brightness matching method with a 2° visual field at fovea at the various retinal illuminance levels of 1 troland through 1000 trolands. At illuminance levels higher than 10 trolands, all the relative luminous efficiency curves showed a broader shape than the CIE V(λ). In some observers the relative luminous efficiency curves became broader with increasing the retinal illuminance. The present experimental results sugges that the brightness perception is contributed from the opponent-color channels.View full abstractDownload PDF (516K) -
The influence of the luminance level upon the functional visual field for detecting a colored targetMitsuo IKEDA, H. UCHIKAWA, M. AYAMA1980 Volume 4 Issue 2 Pages 2_18-2_21
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSThe functional visual field for detecting a colored target out of colored background was determined for various luminance levels covering a range of 0.15 cd/m2 through 30 cd/m2. The background was consisted of two different colors distributed randomly over the field, each color element having a size of 2°×2° arc of visual angle. The visual field had a normal size of about 20° diameter when transformed into an equivalent circular from with a high luminance level, but it contracted down to 8° with the lowest luminance level employed. The importance to keep the luminance level above about 1.5 cd/m2 was shown in order to avoid an extreme contraction of the functional visual field size under the experimental conditions investigated.View full abstractDownload PDF (367K) -
Koichi IKEDA, Koji NODA, Shoichiro YAMAGUCHI1980 Volume 4 Issue 2 Pages 2_22-2_31
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSThe purpose of this study is to investigate the visual acuity as a function of the adaptation luminance with in the range from 0.005 to 4,000 cd/m2. A room with sufficiently wide background luminance illuminated diffusely is set up to provide a visual environment for acuity test. The test objects are Landolt rings with luminous contrast of 92% and with in the errors of size less than ±3% from the standard values. The observers are five male students with normal vision and they judge the break orientations of Landolt rings by guess. Visual experiments are carried out according to the standard method of the visual acuity test. Results obtained are as follows.
(1) The approximate equation of the curve which shows the relation between the resolutionable visual angle θ and the adaptation luminance obtained by the method of least squares is
θ=(0.3775(0.344+L1/4)4)/L(minutes),
where L (cd/m2) is the adaptation luminance.
(2) This equation shows that the visual acuities are lower than those of Moon and Spencer over the whole range of adaptation luminance, and seems to be more practical and more suitable than that of their’s.
(3) As for the relation between the visual acuity and the orientation of the breaks, the visual acuities in the vertical and horizontal directions are a little higher than those in the oblique directions.View full abstractDownload PDF (1839K) -
Masayuki IIZUKA, Kozo ISHINO1980 Volume 4 Issue 2 Pages 2_32-2_37
Published: 1980
Released on J-STAGE: May 27, 2011
JOURNAL FREE ACCESSThe optical matched filtering method has need of a laser source, a photographic film or plate of high resolution, a particular optical system for production of the Fourier transform hologram and for coherent spatial filtering technique. On the other hand, though the digital simulation technique for matched pattern recognition has more or less problems in point of detection accuracy of the pattern in comparison with the optical method, we can simply discriminate a special pattern or a character by carrying out the discrete correlation operation, and by introducing the normalized curve for display. In this paper, the authors examine quantitatively the degree of correlation between an original pattern and a detection pattern by means of a densitometer and by plotting a relative intensity curve of special line direction on the correlation diagram. Moreover, they discuss the matched filtering effects of an original pattern with lightness level difference and that of the numbers of sampling points by using the color display device visually.View full abstractDownload PDF (2661K)
- |<
- <
- 1
- >
- >|