In this paper the authors deal with a research on some characteristics of the shadow on the illuminated plane due to aglobe which is set under a horizontal linear light source as a shadow caster. First, the calculation procedure of the illuminance within the shadow is explained briefly and the calculated values are compared with the measured values experimentally. Next, the shadow characteristics at the varied positions of the globe under the fixed condition of the horizontal linear light source, and vice versa, are described.
Likening a perspective view looking at a cubic source from a calculating point to a flat surface source, the illuminance is readily obtainable by a simple procedure using a modified contour integration formula, even if the shape is complex such as a troidal source. However, the external contour takes on a curious property of tentatively-named “abnormal continuation” when it is in a nearest state being positioned at which an troidal source is looked on its slender side, therefore the correct value of illuminance is unobtainable resulted from a careless execution of the aformentioned definite integral due to the disorder of calculated value. Now, analyzing the cause of such “abnormal continuation” phenomenon is made, and the means of solving it will be p resented hereinafter.
An attempt was made to develop a method to measure simultaneously for twin wavelength regions (from 400 nm to 750 nm and from 700 nm to 2500 nm) using first and second orders diffraction spectra of a grating. The second order diffraction spectrum of a grating, whose first order diffraction spectrum was used for the infrared spectral measurement, was able to be measured precisely for the visible spectrum of light sources. First and second order diffraction spectra of a grating were separated from each other with a cold mirror, so that the visible and infrared spectrum of a light source were able to be measured simultaneously. As a result, visible and infrared spectral measurement was carried out efficiently and precisely with a infrared grating monochromator.
A physiological intensity transform function, y=Xn/ (Xn+Sn); (sigmoidal function) was introduced by examining the stimulus-response relationship in the retinal neural-cell to lightness scale. The responses of the photoreceptor and horizontal cell show that the light intensity is transformed to be nonlinear. Their transform function is the sigmoidal one, which fits to the psychological functions at low light level of the power function and at middle level of the logarithmic one. This function also explained the characteristics of Weber's ratio as a function of light intensity by adopting the effectof light adaptation, and simulated the Munsell gray scale as well as the CIE lightness function.
In order to create the comfortable and pleasant lighting environment, it is required to make both the function and the atmosphhere of the space suitable to the purpose of facilities using lighting installations. Especially in the case of shop, it is important not only to satisfy the functional requirement such as the visual performance of goods, but also to make the atmosphere preferable. Accordingly, it is necessary to develop the techniqueproducing the luminous environment having the required atmosphere. The problem is composed of the following two steps, which require new technical development. (1) To clarify the required atmospheres in the space quantitatively. (2) To develop the lighting method to realize the required atmosphere. Especially in the case of shop, it is important to produce the required atmosphere. Authors studied on the factor analysis in the semantic differential method by experimental appraisal concerning the required atmosphere. Consequently, it is clarified that the important factors are activity, unusualness, modernity and refineme In addition, for example, the required atmosphere for the several shops are shown by using the factor of activity and modern ity.
Of the xenon lamp specified by the Japanese Industrial Standard JIS Z-8902 established in 1965, the spectral power distribution had been previously calculated at wavelength intervals of 5 nm by simply averaging the values measured at wavelength intervals of 1 nm in the region including the line spectra and continuous spectrum. The present paper describes the spectral power distribution of the lamp re-calculated by using weighted mean method, which is a better form for minimizing the error of colorimetric calculation and has been adopted in the new versionof JIS Z-8902-1984.
Semi-cyrindrical illuminance is proposed as illuminance level which shows the brightness of human face and the illuminating space of sports facilities. We made two kinds of experiment regarding the relation between the identification of expression of human face and Semi-cylindrical illuminance as below, and examined its adequacy. Experiment 1; Identification experiment of strips on a cylindrical surface. Experiment 2; Identification experiment of expression of a human face. In Experiment 1, we had the result that there is almost no change in the identification of visual targets regardless thedirection (horizontal angle ψ≥120°) of light if Semi-cylindrical illuminance is fixed. In Experiment 2, it is found that the identification of expression of human face can be determined by Semi-cylindrical illuminance, although the modelling is important factor.