A visual search task such as the detection, discrimination, and separation of a target in a display requires display layout that has been properly designed taking account of color and luminance discrimination properties. Previous investigations on visual search, however, have focused on fundamental analysis rather than practical application. This paper describes (1) color matching properties from the view point of the practical use of complex backgrounds, and (2) conspicuity expressed quantitatively in terms of visual search time and the color differences between the target and the background. Such an expression could help determine the maximum number of colors which could be simultaneously presented to get best conspicuity in a visual display. This paper shows that complex backgrounds decrease the precision of color matching considerably. Color and luminance discrimination data obtained in earlier fundamental investigations may therefore not be applicable to practical applications. This paper also shows that because the presence of a large number of colors surrounding a target increase the noise level and slow a visual search, the maximum number of colors which can be simultaneously displayed in a visual display ranges (depending on the purpose of the display) from 15 to 30.
The main purpose of the work described in this paper was to develop a new lighting design technique to help create a pleasant or comfortable residential living room. Subjective appraisal was studied, using the semantic differential method in order to develop a method for systematizing psychological and physical lighting factors. In this paper psychological factors are classified into two groups, the scale of like/dislike and other scales representing consistent mood of subject impression due to living room lighting. Subjects evaluated the impressions they got from computer graphic drawings that simulated the lighting environment of living room. Numerical values of data was processed by correlation analysis between like/dislike and other scales, and yielded the following results: Scales such as relaxed/active, soft/hard and high-grade/low-grade affected like/dislike in order of strongness of effect. Physical lighting factors such as wideness of local lightings, those number and luminance contrast affected relaxed/active in order of strongness of effect. The followings were important for making relaxed atmosphere. Luminaire on the ceiling should light toward local area rather than general area on floor. Living room should not have many luminaires. Luminance contrast should be neither too high nor too low, and a low color temperature is better than a high color temperature.
An investigatioll of time-depelldellt simulation model for the high pressures odiuln arc based upoll an energy balance equation has been carried out First, at the initial time poillt arc temperature distribution was calculated by using the lamp currellt at that point. Next, using this initial arc temperature distribution, the arc temperature profile change with time was calculated by the time-dependent energy balance equation. Within ten cycles converged arc temperature distributions in one cycle could be obtained. In pulsed operation the arc center temperature increased compared with direct current operation having same lamp currellt as the peak pulse current. As a result, in pulsed operation Na D-lines emission decreased and Na non-resonance line emissions increased compared with sine wave operation. Continuum radiation near 450nm was treated as NaHg molecular spectrum takillg into account its temperature dependellt absorption coefficient. Using this method, calculated increase rates of contilluum radiation near 450nm in pulsed operation were coincident with measured values-Taking account of these effects calculated result of correlated color temperature increases in pulsed operation was obtained.
The chlorophyll fluorescence spectra of green plant leaves induced by a visible laser have strong emission peaks near 685 and 740nm. In order to examine transverse distributions of illuminated laser light and laser-induced chlorophyll fluorescence (687nm: F687 and 741nm: F741) within rice leaves, a micro-fluorescence imaging (MFI) system was devised using a microscope, a CCD camera with an image intensiffer, Ar lasers oscillated with 488and 514.5nm and a He-Ne laser, an image processor, and a microcomputer. Transverse distributions of illuminated laser light and chlorophyll fluorescence in leaves which were projected on the surface of rice leaves with different chlorophyll contents were measured at laserlights with various wavelengths (488, 514.5, and 632.8nm). The distributions of light projected at 541.5 and 632.8nm were observed at a greater depth from the leaf surface than that at 488nm. The attenuation curve of incident laser light in the mesophyll tissue was approximated by an exponential function and it fit well. As a result, the attenuation coefficient α of incident lights of various wavelengths and leaves with different chlorophyll contents could be determined. In order to examine the self-absorption from distributions of the chlorophyll fluorescence in leaves with different chlorophyll contents, profiles of the F741/F687 ratio within mesophyll tissue were measured at various wavelengths. The F741/F687 ratio increased in the case of light with a high absorption coefficient by chlorophyll. We conclude that the MFI system is a useful method to study in order to select the spectral quality of light for plant irradiation.
In order to evaluate the Helmholtz-Kohlrausch effect, heterochromatic lightness matches on 64 Munsell colors of 4/were made by 26 obsevers, and 88 Munsell colors of 6/by 24 observers. A bipartite field subtending a visual angle of 3°×3° with a surround was used. A surround of N4 was used for the test colors of 4/and of N6 for those of 6/. All heterochromatic lightness matches were made under fluorescent light (x =0.3126, y=0.3168; 4551x), and the viewing geometry was normal (0°) illumination with approximately 45°viewing. The individual data obtained by all observers and also their means are given in tabular form and the latter are also given in graphical form. The mean data were examined on the basis of the CIELAR color space, then an experimental formula was derived which gives the correlate for lightness of a surface color in terms of L*, C*, and h°. These results are compared with similar ones reported previously by other researchers. The results obtained in the present study indicate that the lightness of surface colors may be substantially predicted by a rather nonlinear equation of C* than linear one and there is a weak trend whereby the Helmholtz-Kohlrausch effect on surface colors having constant value of C* shows another shallow minimum at h°=300 which has never been reported.
The purpose of the present study is to describe the subject of the presnt CIE method of specifying color rendering properties of light sources and to propose a revised method to solve the subject. The revised method is as follows: (1) Test color samples consist of eight colors selected from the MacBeth Color-Checker with two actual skin colors added.(2) 5reference illuminants are selected.(3) CIE LAB color space and CIE chromatic adaptation transform are used to calculate the color rendering indices of light sources. The revised Ra values by this proposal correlated well with the Ra values of the present CIE method. A part of revised method of this proposal was suggested to CIE TC1-33.