A sensitive antenna attached to the rear window of a car has been designed for diversity reception of digital terrestrial television broadcasting. The proposed antenna efficiently utilizes heat wires located on the rear window and the antenna elements to improve the directive gain in the horizontal direction. The field tests show that the proposed antenna using heat wires gives an antenna gain of 2.5 dB compared to the conventional rear-window half-wavelength dipole antenna. By computer simulation, we also show that the proposed diversity scheme, which is composed of two wire antennas with heat wires, can improve the gain in the front direction.
Using a digital camera with a fisheye lens, we measured the incident light at the surface of a mobile display in 112 different environments, including outdoor and indoor environments, and the interior of a car. The data were analyzed the some typical environments in which mobile displays are used. The results were usedto evaluate the clarity of reflective or transflective LCDs and to establish a method for measuring the reflection properties of mobile displays.
We investigated how luminous efficiency depends on the distance between the principal discharge portion and stripe rib for PDPs using DDF (Discharge Deactivation Film). We expected that luminous efficiency would increase with the distance because the plasma energy loss due to collisions against the rib walls might be smaller. Howeverthe experimental results shows a different tendency : the efficiency is maximized at an optimal distance. This tendency is significant when a gas of Ne-Xe10% (by volume) at 600 hPa is used instead of Ne-Xe5% at 700 hPa. To explain this, we hypothesize that higher Xe partial pressure causes a greater decline of generated UV radiation due to self-adsorption. Using the former gas condition, the luminous efficiency is maximized when the principal discharge portion nearly touches the rib in the plan view. We estimate that the optimal distance for our 46-in. HD PDP model is around 10m.
Calculating an induced field is generally complicated even if an optical illusion phenomenon makes the shape look simple. In addition, a technique did not previously exist for explaining an optical illusion in a figure with line width. This paper describes a method for estimating the quantity of optical illusions of a figure by composing an induced field to produce a figure constituted by arranging multiple points. We first clarified that the quantity of estimated optical illusions resembles the felt optical illusion phenomena. Next, we quantitatively estimated the weakened effect of optical illusion phenomena for figures, and, we also quantitatively estimated the influence of line width on optical illusion phenomena.
We propose a robust road sign recognition system under various illumination conditions. The proposed approach has two steps : segmentation and recognition. The segmentation, which is the focus of this paper, is performed using morphological operations and relative color. The segmented regions are recognized by a template matching method using modified standard deviation. The algorithm works for various types of circular and pentagonal road signs.In experiments under various illumination conditions, the segmentation rate was 100% in the daytime and evening and 80% even in the night-time, and the recognition rate was 100% for all of the segmented regions under all illumination conditions. The effectiveness of the proposed system was confirmed through experiments using 200 images of road signs taken under a great variety of illumination conditions including fog and light rain.
This paper clarifies the relation and characteristics of the accommodation and motion detection mechanisms while multiple apparent motion stimuli are being observed. We made these clarifications by measuring the correspondence between motion appearances and accommodative responses to double apparent motion stimuli consisting of two kinds of sine-waves shifted abruptly in opposite directions. We found that (1) a critical spatial frequency exists where two kinds of motion appearances (capture and transparency) dependent on attention change into one kind of motion appearance (capture) independent of attention, (2) different accommodative states are induced depending on the differences in motion appearance under the critical frequency and in spatial frequency structure over the critical frequency, and (3) the above results are independent of the average temporal frequency and the frame number per period of the apparent motion. These results suggest that the relation of the two mechanisms is also cooperative for multiple apparent motion stimuli and is independent of the degree of their intermittent motion.