Computer graphics have become indispensable to the confirmation and evaluation of three-dimensional luminosity in lighting plans. However, when we simulate lighting environments using monochromatic light sources such as low pressure sodium lamps, red and green do not come out, because in calculation of object color, most computer graphics systems convert the spectral distribution of light source and the spectral reflectance and transmittance of objects to red, green and blue values. Here, we report a technique that solves this problem. First, each object color is obtained from the spectral distribution of the light source and the spectral reflectance or spectral transmittance of each object. Those values are then input as attribute data for objects into an existing computer graphics system. The results confirmed that the problem of color reproduction is solved without increasing the computation load. The results also demonstrate that computer graphics can simulate low pressure sodium lamp lighting in tunnels.
An objective method for deriving the luminance difference threshold of the eyes adapted to the actual non-uniform field of view was developed by Narisada et. al. This method is based on the theory that an additivity law between the luminance difference threshold determined by the foveal adaptation luminance and that determined by the equivalent veiling luminance exists, but that theory had not been verified experimentally. Therefore, in the present study, the luminance difference theresholds of eyes adapted to fields consisting of various combinations of foveal adaptation luminances and veiling luminances were obtained by observations. These thresholds were compared with those caluculated for the same conditions of adaptation by using the method of Narisada et. al. Because the luminance difference theresholds obtained by observation agree well with those obtained by calculation, it is concluded that the theory has been verified experimentally.
We made a nagative glow lamp (having no positive column), measured the plasma characteristics of that lamp, and found that the characteristics of this plasma depend only on the distance from the cathode, and that there seems to be two groups of electrons in the negative glow. We therefore made the following hypotheses. (1) There are two groups of electrons in this plasma, here called first electrons and second electrons. The first electrons are emitted from the cathode and accelerated by the electric force of the ion sheath. They collide with nothing in the ion sheath, and their energy in the plasma is determined by the cathode fall voltage. The second electrons are the electrons created by two ways. One way is as a result of the inelastic collisions of the first electrons and neutral atoms. Another way is as a result of the ionization between other second electons and excited atoms. And they disappear by ambipolar diffusion. (2) In this plasma there is not the accelerating electric field, which exists in the positive column, but there is the electric field produced by diffusion. The second electrons are given their energy by the collision of electrons, not by the electric field. And the energy of the second electrons is constant in any place of lamp. we calculated the continuity of the electron density, the continuity of the current, and the continuity of the energy, and we got results that agreed with the measurement results.
We compared the concentration of subjects under general illumination, where the ambient illuminance was equal to the task illuminance, with the concentration of subjects under partial illumination, where the ambient illuminance was lower than the task illuminance. The level of concentration of the subjects was evaluated by subjective appraisals, observations of the behavior of the subjects, and measurements of lambda responses (a brain response). The subjective appraisals showed that the subjects found it easiest to concentrate on routine office duties under the general illumination, but they found it easiest to concentrate on more intellectually demanding duties like planning and studying under the partial illumination. Observations of subject behavior and lambda responses measurements clearly showed that the subjects could concentrate better on their work under the partial illumination than they could under the general illumination when they had to do both intellectually demanding duties and just routine office duties. Furthermore, it was confirmed that subjective appraisals, objective evaluations such as observation of subject behavior and measurements of physiological responses are indispensable in evaluating the influence of illumination on the concentration of subjects.
The CIE daylight illuminant is based on the data measured about thirty years ago at high latitudes in the northern hemisphere in the U. S. A., Canada, and England. A similar measurement was made at Amagasaki and Nagaoka in Japan, and the result was compared with the CIE daylight illuminant. The typical daylight loci in the two Japanese cities intersected the CIE daylight locus in the range of high color temperature; in the visible range the spectral distributions were almost the same as the CIE spectral distributions, but in the ultraviolet range the spectral energy was somewhat higher than that of the CIE. The purpose of this work was to measure the spectral irradiance from the north skylight at Atsugi and to compare the spectral distributions of the reconstituted daylight calculated from the data measured with those of the CIE daylight illuminant. The typical daylight locus on the (x, y) chromaticity diagram at Atsugi was expressed by the quadratic equation: y=-1.850x2+2.101x-0.1520, and the locus intersects the CIE daylight locus at about 14000 K, deviating from the CIE daylight locus to the purple side at low color temperatures and to the green side at high color temperatures. In the visible range, the spectral distributions were almost the same as those of the CIE, but in the ultraviolet range they were slightly lower than the spectral distributions of CIE daylight illuminant.
According to the theory of the recognized visual space of illumination (RVSI), a space can be made brighter by arranging colored furniture as the initial visual information, as previously confirmed. A question about the effect of number of pieces of furniture remained and the present investigation therefore measured the brightness of a miniature room in which pieces of colored furniture was varied from 0 to 6. The brightness increased markedly as the number increased from 0 to 3, but further increases did not affect the brightness of the room greatly. Further analysis found no strong correlation between the brightness increase of the room and the area of the furniture in the visual field of the observers. This implies that it is mostly the number of pieces of furniture of different colors that affects the room brightness.