Fuzzy reasoning has been used in the control of various types of electrical equipment, temperature control, traffic systems, and so on. Conventional lighting control methods have been investigated to save-energy and for amenity in lighting apparatus. Since those conventional controls employ sequential control, they do not exactly satisfy human expectations. We applied fuzzy theory to the lighting control of fluorescent lamps so as to satisfy human expectations. This report describes a lighting control model that uses fuzzy reasoning, and the control characteristics produced by several typical reasoning methods. The results verify the utility of this fuzzy lighting control.
One can immediately judge the state of illumination of a room by observing various objects in the room such as furniture and wall paper. The appearance of the objects, e.g., their color and brightness, constitutes the initial visual information about the room, and the recognized visual space of illumination, RVSI, of the room that the observer gains is based on that information. The observer's later judgment about the appearance of objects in the room is based on the RVSI. Here, we consider the interaction between RVSIs for two rooms connected by a window of variable size: one for an observer's room with Dlight type illumination and the other for a test room with Alight type illumination. The RVSI of the test room was evaluated by measuring the appearance of colors of nine test color charts placed in the test room as a function of the illuminance of the observer's room, which was varied between 0lx and 270lx, with the illuminance of the test room constant at 270lx; it was also measured as a function of the window size. The RVSI of the test room was not affected by the RVSI of the observer's room for the illuminance of 0lx through 1lx, but it was affected for illuminance above 1lx, and the effect increased for higher illuminance values. A greater effect was also found for smaller windows. The direction of color change of the color charts varied along the hue circle, depending on the hues. That phenomenon was explained using a chromaticity diagram.
We performed a visual experiment to determine the characteristics of discomfort glare caused by a flashing light in the periphery of the visual field. Subjects adjusted the luminance of a flashing light and a steady light to the borderline between comfort and discomfort (BCD) at various flashing frequencies and retinal eccentricities. The results show that the BCD decreases as the flash frequency increases between the frequencies of 0.25 and 4 Hz. In the periphery, the BCD of the flashing light at upper vertical positions is greater than that at lower vertical positions. The BCD is higher for the steady light than for the flashing light, regardless of the retinal eccentricity. The BCD of the flashing light can not be obtained from the effective value calculated using the Blondel and Rey equation.
Analysis of light scattering by atmospheric particles is useful for studying theappearance of light signals. The spatial distribution of scattered lamplight was calculated by Monte Carlo simulation. Comparison of simulation results with measured values revealed that 1) the simulation results agree well with the measured values, 2) the maximum times of scattering in the simulation must be increased as the optical depth increases, and 3) when simulating airport lights, the maximum scattering times should be about60 for optical depths of up to 10 and calculation error of less than 1%.
Analysis of how lamplight scattering affects the visibility of lights is useful for determining the optimum operation of a light signal system. However, the accurate measurement of particle size distributions and other such requirements have so far prevented the accurate analysis in fog experiments. We performed an experiment involving observation of the light signal system using the computer-generated images that take account of scattered light. The results revealed that 1) for matrix lights, the adverse effect of scattered lamplight on visibility becomes severe as the number of lights increases, 2) for airport lights, scattered lamplight has a worse effect on the visibility of the runway lights than dose that of the approach lights, because the runway lights are located behind the approach lights in the landing route, and 3) the effect of scattered lamplight on visibility varies with the particle size distribution, the optical depth, and the method of measuring transmittance.
This paper describes a method to measure the spectral responsivity of an infrared detector by using two Fourier-transform infrared (FT-IR) spectrometers. The principal part of the measuring system consists of the two FT IR spectrometers, a silicon-carbide infrared cavity radiator, and an optical arrangement to measure the spectral radiance with the FT-IR spectrometers. The measurement of an spectral responsivity of an infrared detector by this method consists of two steps. The first is measurement of the spectral radiance of interferogram at an optical path difference of zero on an FT-IR spectrometer, and the second step is determination of the spectral responsivity by combining the FT-IR spectrometer measurements with the known spectral radiance at an optical path difference of zero. In the experiment, the infrared detector used was a liquid-nitrogen-cooled HgCdTe photoconductive detector, and the spectral radiance of the interferogram at the optical path difference of zero on an FT-IR spectrometer  was determined by a comparison with that of the silicon-carbide infrared cavity radiator using an FT-IR spectrometer . The spectral responsivity of the HgCdTe detector was measured by combining the above FT-IR spectrometer  results with the known spectral radiance at an optical path difference of zero. The results of these experiments suggested that our proposed methods are effective for measuring the spectral responsivity of an infrared detector.
Indoor evaluation experiments have been carried out on the perception of the brightness of car speed indications projected by an automobile head-up display (HUD). We did two types of experiment. One was to examine the influence of the observer's age on the evaluation data. The observers were to determine the appropriate brightness of the HUD as it changed from dark to bright (ascending order) and from bright to dark (descending order). The observers were categorized by age levels (in their 20s, 40s, or 60s). The other experiment had observers evaluate the brightness while we interfered with their observational concentration by having them do subsidiary tasks during the evaluation. As well as the subjective evaluation results, we also examined electrocardiograms from the subjects to calculate the RRV (R-R Variance), which expresses the extent of a mental load. The main results are: (1) The range of HUD brightness judged as appropriate is narrower for older people than for younger people. (2) Subjective judgments of HUD brightness perception changed when the observers also had to do a subsidiary task. In other words, evaluations range from too bright or too dark to neither too bright or too dark. (3) The RRV values revealed that the extent of the mental load differs according to the nature of the subsidiary task. When there was a heavy mental load, an observer's subjective judgments changed considerably.
Concerning the continuous dimmer circuit with a TRIAC for a high pressure mercury discharge lamp, the authors propose an new operating circuit through which current is nearly sinusoidal and runs with power factor close to 100%. We connect the by-pass circuit to the tap at the point of near the power source side. The self-inductance employed here is larger than the one for conventional ballast. It is shown that the operating circuit, of which the input current is sinusoidal with power factor of 100%, is realized, by adjusting the circuit constant, self-inductance L, self-inductance of choke coil of by-pass circuit Lb and capacitance Cb to appropriate values for each firing angle of TRIAC.