This paper proposes a method for estimating three-dimensional (3D) motion parameters of a rigid object, of which surface is covered with a texture, by three images from a single camera. The method estimates unit normal vectors of texels and the 3D shape of the rigid object in each image by using a Shape-from-Texture technique. The rotation parameters are obtained from average vectors of the normal vectors at the three images. The translation parameters are determined as the displacement between the centroids of successive shapes. Based on the 3D motion parameters, a correspondence between texels in successive images is established. The correspondence can provide a more exact shape of the object through stereo triangulation. The estimation of exact shape and 3D motion parameters should prove to be useful technique for the content-based image retrieval.

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As reflected by the launch of satellite digital broadcasting in Japan at the end of 2000, the trend toward more advanced multimedia-oriented broadcast programs is gaining momentum. To deal with this trend and to support program production work in an efficient manner, we previously proposed a hierarchical program-information management structure that can be used throughout the program-production process, from planning to recording, editing, and secondary use. Using this structure, we have developed a hierarchical program-production technique and used it to construct a prototype system. The new technique was tested at a program-production site and was found to be efficient in terms of managing and reusing program information, and highly useful in providing a comprehensive view of story development. This paper describes the proposed technique and its features and presents an overview of the prototype production system.

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The study on image-based method, such as image-based rendering, image-based object, promotes a new problem called Image-based Shadow Generation. Image-based shadow generation aims at generating new shadows from a few reference images. As a start of the image-based shadow generation problem, building, as a representative of man-made object, is chosen as our study object in this paper. To solve the problem of image-based building shadow generation, we propose a new technique called shape from shadow silhouette, which reconstructs 3D model of building. This technique consists of three steps : shadow extracting & transforming, shadow complementing, and shape modeling. By this technique, the rough 3D model of building can be recovered from several reference shadow images, then new shadow can be generated easily and quickly by this recovered model. The experimental results are given in this paper. The efficiency of our approach is demonstrated by the results.

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[in Japanese]

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[in Japanese]

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We introduce a temporal-spatial picture model, analyze the spectra of pictures in flat displays, and discuss the effects of spatial or temporal specifications of pictures on picture quality. We found that reducing the inter-pixel gap every two pixels to increase brightness or resolution results in uneven pixel pitch. An appropriate rate of unevenness produces higher brightness or resolution and improves overall picture quality. We also found that the use of a field dispersed PWM, which disperses the driving pulse to increase the apparent field frequency, repress the flicker that often occurs with high brightness or large size displays. Moreover, we found that using a TV camera to shoot pictures for the display of a field dispersed PWM results in good picture quality and enables image signals of different field frequencies (such as NTSC or PAL) to be displayed normally. These findings are important steps toward the goal of achieving high-quality tiled displays.

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For the purpose of the improving luminous efficiency of PDP, a cathode featuring a low discharge voltage has been developed employing a thin film of Al electrode covered with Y₂O₃. This structure enables the cathode to have long life. By applying the Y₂O₃/A1 cathode, the DC-PDP can be operated using 100 V less than an ordinary panel can be using an Al cathode. In comparison to MgO as a protecting layer of AC-PDP, the Y₂O₃ has excellent secondary electron emission characteristics. In order to clarify the conduction mechanism, which is necessary for a dc discharge, the surface and depth profile of the cathode is examined with SEM, RBS, and AES. Many small cracks are found in the Y₂O₃, which are caused by the high-temperature process. From the cracks, an Al cathode bus line is sputtered during the aging process and the surface of the Y₂O₃ is covered with a thin island-like Al film and a conduction path is formed through the cracks.

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We previously developed a field-sequential stereoscopic display system with a 42-inch diagonal HDTV DC-type plasma display panel (PDP). This system uses an LCD shutter stereoscopic eyeglass, synchronized with the left and right pictures on the display by infrared signals. Stereoscopic images were displayed on the PDP using the proposed light emission scheme and gray-scale signal processing. However, it was found that cross-talk impairment was incurred due to leakage between light for the left and right images. We calculated the amount of cross-talk as a function of phosphor persistence and decay time and estimated the desirable decay time for a field-sequential stereoscopic display system. This enabled us to develop a signal processing method for reducing the cross-talk impairment, and a subjective evaluation confirms the effectiveness of the method.

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In video processing, compression techniques are required to improve the efficiency of transmission and storage of video data. Data compression methods can be classified into two basically different categories : lossy compression methods and lossless compression methods. Lossless compression methods are required for medical image processing and for compressions broadcast materials. We developed a novel video lossless compression method using the Hilbert curve, by mapping the three-dimensional data to one-dimensional data along the curve and then applying adaptive linear prediction coding to the one-dimensional data. Experimental results show that better compression ratio is obtained with our method than with lossless JPEG, although the processing time for both methods is almost equal.

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The purpose of this paper is to clarify the effects of visual information on corresponding auditory information when they are presented simultaneously in a wide frontal area (180 degrees) on a horizontal plain. Sound localization experiments were carried out both with and without visual stimuli associated with sound stimuli. In the experiments, four different visual images of a human speaker and the four corresponding speech sounds were used as the visual and sound stimuli, respectively. The visual stimuli were projected on a half-cylindrical shaped screen in five directions (-60, -30, 0, 30, 60 degrees), and the corresponding sound stimuli were reproduced in 13 directions (-90, …, -15, 0, 15, …, 90 degrees) via loudspeakers placed in each direction or transaural reproduction using a pair of loudspeakers (±30 degrees). The degree of sound localization accuracy was evaluated according to a five-grade system in cases where visual stimuli were absent. The results obtained showed that a sound image far away from its corresponding visual image (maximum 150 degrees) was affected by the visual image, and that a sound image having a relatively low degree of localization accuracy tended to be strongly affected by the visual image. These results show that, in addition to the relative position of visual and sound stimuli, the degree of sound localization accuracy is one of the important elements in auditory-visual interaction on a wide frontal area.

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In this paper, we propose narrow element spacing arrays consisting of level sensitive phase multipliers (LSPM). A level sensitive phase multiplier comprises down converters, frequency multiplies with a phase locked loop (PLL), and an amplitude modulator.
In order to confirm the capability of these arrays, we first examine the receiving patterns of two element arrays using the half wavelength dipoles and three element Yagi-Uda antennas. The number of the multiple function “n” is set to ”2” for measurement. The experimental results show that the quarter wavelength spacing arrays with LSPM have the equivalent receiving pattern of the half wavelength spacing arrays without LSPM. Second, the four element arrays using inverted-F antennas with LSPM, which have a 0.2 wavelength spacing, yield the equivalent pattern of a 0.8 wavelength spacing arrays without LSPM. In this case, the multiple function “n” is set to“4”.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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