Improvements in image processing have recently resulted in the wide use of inspection systems. The lighting technique in such systems is very important because the quality of the image is determined by the illumination. Furthermore, the quality of the image determines the cost, speed, and stability of the inspection system. It is therefore necessary to consider what kinds of lighting technique are most suitable for each object, but there are a only few studies on lighting technique. The present theoretical study investigated how much difference was obtained by the difference of lighting technique. The brightness or intensity on the surface of a model printed circuit board was calculated by using Monte Carlo method. This study confirmed the effectiveness of supplementary light for inspecting a three-dimensional object.
The Sky can be classified according to the amount of cloud as clear sky, overcast sky or intermediate sky (where clouds are scattered), and the skylight that comes to a horizontal plane of the ground from all sky components is respectively called clear skylight, overcast skylight or intermediate skylight. This paper discusses the correlated color temperatures (CCTs) of the clear skylight, the overcast skylight and the global light that is composed of the clear skylight and direct sunlight. Consequently, the mean CCTs of clear skylight and global light for atmosphere of annual mean atmospheric transmittance in Japan, 0.70, based on visible radiation rather than on the amount of direct solar radiation, are respectively estimated to be 8000K and 5900K. The CCT of covercast skylight is similarly estimated to be 6200K, which is almost the CCT of extraterrestrial sunlight.
An investigation of the high pressure sodium arc simulation model with an energy balance equation has been carried out. Arc temperature profiles are calculated by a relaxation method taking account of an energy balance equation for thermal conduction, radiation and input power. The method involves calculation of the radiation flux density as a function of radius for a given temperature profile using an integral solution of the radiation transport equation. The line shapes of both atomic and molecular spectra have been assumed to be optically thick. Atomic spectra are calculated for resonance broadening and Stark broadening. Mercury contributions on the red wing of Na D-lines and continuum spectra near 450 nm are also taken into account. Calculated results were compared with measured data and comparatively a good agreement has been attained over the wide lamp parameter region.
“Visual Clarity” or “Brightness Sensation” of colored objects changes by changing the color rendering properties of light sources. Though visual clarity is considered one of the most important characteristics of the color rendering properties of light sources, it can not be estimated adequately by using the present CIE Ra method. For this reason, we studied the cause of visual clarity and confirmed that visual clarity was caused by the feeling of contrast between the colored objects under the illumination. In addition, we proposed the method for predicting the illuminances for the same feeling of contrast under various light sources, based on the gamut area made by the four component colors of a four-color combination in a brightness and colorfulness space. The purpose of the present study is, furthermore, to develop an estimation method of the feeling of contrast under test light sources and to propose a new index of the feeling of contrast under a test light source by using a simple transformation of the gamut area derived under the light source. The new proposed index correlated well with the illuminance ratio for equal feeling of contrast (or equal visual clarity) on various light sources reported so far. The new index is compared with the other indices, such as General Color Rendering Index Ra, Color-Discrimination Index and Flattery Index, and it is confirmed that the new index is a different measuring index from these indices. By using the new method proposed in this paper together with the present CIE Ra method, the color rendering properties of light sources can be well estimated from various points of view.
A new electronic ballast for electrodeless fluorescent lamps using a zero-voltage-switched resonant inverter is presented. The characteristic of this circuit is analyzed using an equivalent circuit of an electrodeless lamp. From the analysis, the output power of the electrodeless fluorescent lamp, the semiconductor device's stresses and zero-voltage-switching condition are derived, and a procedure for designing the electronic ballast for an electrodeless fluorescent lamp is established. The analytical results are compared with the experimental results obtained under 10MHz operation. This circuit realizes both condition of applying high resonant voltage across the excitation coil within the rating of the switches at the start of the lamp and lighting the lamp stably at the rated output power. In the experiment of 10MHz operation, the conversion efficiency over 90% is realized by zero-voltage-switching.
This paper describes an attempt to represent three-dimensional color distribution in lighting rooms using Monte Carlo simulation (MCS). Generally speaking, the lighting space is usually expected to have different spectral radiant exitances and color distributions in various positions throughout it, since lighting rooms have many types of light sources and room surface walls with various spectral properties. Because the human being perceives a color stimulus with his eyes from a wide visual field, it is important to discuss three dimensional color distribution with regard to human vision at any point in the lighting space. A formulation for the Monte Carlo simulation technique is performed to estimate three dimensional color distribution as quantitively as possible. Firstly, the model room is composed of imaginary 1, 000-unit subdivisions formed by uniformly dividing the lighting room into many single unit spaces. Next, the three-dimensional color distribution on six specified surfaces of a single unit space in the lighting room is investigated by using MCS It was found that spectral radiant exitance distributions on both sides of the imaginary partitions are quite variable according to their positions and human perceptual location, so three-dimensional color distribution is also complicated by variations in these factors.
In order to clarify the relationship between the evaluation of the complexions of Japanese women and their chromaticity coordinates for various chromatic adaptations, a series of experiments were conducted. The complexions of three female models were estimated under 40 kinds of illumination by the semantic-differential method using 31 adjective pairs rated by 20 observers on the chromatic adaptations of 3000K and 4200K, to compare them with previous results on the chromatic adaptation of 6100K. Evaluations of human complexions under the illuminations were determined by two main factors, “activeness” and “refinement” on various chromatic adaptations. The factor score for “activeness” correlated well with the u' value of the corresponding color to D65 adaptation using the CIE chromatic adaptation formula, when it was less than 0.25. The u' value of about 0.25 was the maximum value for the evaluation of“activeness”. The highest factor score for“refinement” had almost all the same chromaticity coordinates for the various chromatic adaptations. The factor score became lower as the chromaticity coordinates of the human complexion under the illumination became further from that having the highest factor score.
The dependence of 253.7 nm emission efficiency on the discharge tube radius in argon-mercury-mixture gases is investigated using the simulation model for a positive column. The calculated waveforms of electric field, 253.7nm emission, electron energy and electron density show good agreement with the measured waveforms, respectively, for 50 Hz and 50 kHz operations. The obtained results are as follows: (1) The 253.7 nm emission efficiency takes a maximum with the tube radius under the constant discharge power and the constant mercury atom density condition, even though the dependence of emission efficiency on the discharge tube radius is rather weak except for the small radius region.(2) At the large radius region, the effective radiative decay-time increases with the radius. The density at radiative excitation level also decreases with the radius due to the decrement of electron energy and electron density. Thus, 253.7 nm emission decreases even if the discharge volume is increased.(3) At the small radius region, the increasing rate of the density at radiative excitation level begins to decrease with the radius, since the excited atoms at the triplet levels are excited to higher levels. Thus, 253.7 nm emission decreases with a decreasing discharge volume.
The luminous flux transfer method has been used widely as a calculation method of the illuminance distribution on a working plane in interior lighting. However, the conventional method was considered inapplicable in case of unempty room with louvered light sources. In this paper, we propose a new method to calculate the illuminance distribution on the working plane in a room with louvered light sources. This new method is based on the assumption that the luminous intensity distribution for louvered light source can be represented as a polynomial expression with the components of cosine to the nth power. The illuminance distribution on the working plane was calculated by the sum of the illuminance of each component of the luminous intensity distribution. The illuminance distributions on working plane calculated by this new method are in good agreement with the measured results. The new method is simple and saves time. It may also be used to solve a kind of interreflection problem without difficulty.
The crystal field splittings of the Eu2+ ion have been calculated with the eigen functions |f6 α1S1L1, sd1;SLJMJ>. The equation for calculating matrix elements of the crystal field Hamiltonian (Hc) was derived from the application of the tensor operator technique. The calculation was carried out for both O h and D 3h symmetries. Complete equality between calculated results and related predictions with the group theory could justify this derived equation. Further energy splittings with the lowest excited multiplets of a Eu2+ free ion were calculated from the matrix of Hamiltonian H=H c+Hel + H so using eigen functions |f6 α1S1L1, sd1;SLJMJ>. Here, Hel and H so denote electrostatic interactions and spinorbit interactions, respectively. It was shown that the lowest excitation levels in arbitrary symmetries could be easily obtained from a single matrix, even in the d-f coupling scheme.
The laser-induced fluorescence (LIF) method is a useful technique to examine activities in the growing process of plants. In this investigation, a LIF system was devised using an optical multichannel spectrometer, and Ar laser and He-Ne laser lights for excitation. Fluorescence spectra were measured for intact leaves of rice plants with various amounts of nutrients, and rice chlorina mutant plants lacking in chlorophyll b and chlorophyll contents. The chlorophyll fluorescence spectra of rice leaves had two peaks at around 685nm (F II) and 740nm (F I) in relation to photosystem II and I, respectively. These chlorophyll fluorescence spectra showed changes depending on the chlorophyll contents and various amounts of the chlorophyll a/b ratio. The ratios of the two peaks (F I /F II) were proportional to the amount of chlorophyll contained in the rice plant leaves. we conclude that the mesurement of laser induced fluorescence is a powerful method for the study of the activity of plants in the plant factory.
Two psychological experiments were camed out to evaluate visual comfort to a colored environment. One measured the number of colors contained in the colored image of a natural scene briefly presented on a CRT display by asking the subject to report all the perceived colors based on the categorical color naming technique. The other measured the optimum rate of chromaticness at which the subject felt the most comfortable impression against the scene when the chromaticness of every point of the colored image was gradually changed at the same proportional rate to the original chromaticness of each point. The results showed that the direct estimation of comfort to an image was in good negative correlation with the number of categorical colors, and in good positive correlation with the optimum rube of chromaticness. It was concluded that the both the number of categorical colors and the rate of chromaticness employed here were useful measures for evaluating visual comfort to a colored environment.
In a situation where an observer stays inside of a room and looks at the outdoor scene through an window, he obtains two recognized visual space of illumination (RVSI) for the respective spaces. These two RVSIs differ normally as the illumination situation differs between the two spaces. It is possible, however, to equate them by controlling the illumination situation of the room, where the observer experiences a feeling of continuity between the two spaces. By using a normal house as the experimental place the illuminance of a dining room was obtained to assure the continuity point during early morning as well as toward the sunset. It was found a simple linear relation exists between the illuminance in the room and that in the outside when the values were expressed in logarithmic unit. It is suggested to employ the relation to control a room illumination in order to offer the residents the amenity.