In recent years, a communications system, the Body Area Network, which uses the human body as a transmission path has attracted attention, and there is increasing expectation that it will be used more widely. However, there are still several points on the signal transmission mechanism of using the human body in this way that remain to be clarified, and there has been little research into the interaction of electromagnetic waves and the human body. Therefore, we used the Finite Difference Time Domain (FDTD) method to calculate the Efield distributions around simple and realistic models of the whole human body in free space with a weareble device. Moreover, E-field calculations were carried out when the positions of the body were changed. Our results show that using the simple homogeneous whole human body model is valid for the E-field calculation, and the dominant component of the E-field is normal to the body/air interface in all the positions that the human body assumes in daily life. Furthermore, in the state where the human body is shunted to the Earth ground, it was shown clearly that the E-field distribution is not mostly different from when a body is floating in free space. It can be concluded that these results provide useful information in improving the design of wearable devices.

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Many recent studies of distributed-display environments discuss how to augment large workspaces with mixed reality technology. In addition to overcoming the difficulty of directly touching virtual objects located where a user cannot touch them in such large space environments, the usability of a distant access interface, which determines the total usability of the hard-to-reach objects, is the key issue in these studies. In this paper, we first discuss the metaphor of a shadow cast by a user's palm and extend it to a media as a user interface in augmented environments. Then, we introduce a new intuitive accessing method using hand gestures by image recognition. The proposed system, PALMbit-Silhouette, provides a distant user interface that enables a user to move an icon among distributed large displays with natural grasp-and-release gestures. Experiments with a prototype system showed that it enabled users to interact seamlessly with virtual objects in distributed-display environments.

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We have been studying an advanced satellite broadcasting system which is aimed at improving the Integrated Services Digital Broadcasting for Satellite (ISDB-S) system. By making use of LDPC codes and the reduced roll-off factor, this advanced system can increase its transmission channel capacity to 30% that of the ISDB-S one. Furthermore, by applying multi-level amplitude phase shift keying (M-APSK) modulation schemes, we can increase the transmission channel capacity. We report on LDPC codes that are designed for the transmission format of the advanced satellite broadcasting system. The computer simulation results of B/Q/8PSK performances under the AWGN channel model are also reported. We also discuss and report the optimization result gained from a computer simulation of the radius ratio of LDPC-coded 16APSK and 32APSK modulation, which is proposed in this advanced system, with respect to Bit Error Rate (BER) under the AWGN channel model.

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We investigated the effect of asynchronization between visual and auditory stimuli of speech movies upon the correct acquisition of the speech contents under various auditory-noise-conditions. We presented movies of a female announcer's face uttering short sentences to subjects who were asked to repeat the sentence aurally. All sentences consist of five words of the same word order (subject time location object verb). The utterance speed was 120 or 150 ms/mora. Audio-visual asynchronies were 0, ±1, ±2, ±4, ±8, ±16, and ±32 frames (1 frame = 1/30 s, +: visual preceding condition, -: audio preceding condition). Pink noise of -10 dB or -15 dB was imposed on the speech sound. The same procedure was done using the stimuli with no visual image (audio-only) as a control. Increase of word recognition rate compared with the level of audio-only was found within an asynchronization of ±4 frames delay indicating that the facilitation by visual information occurs within that period. On the other hand, a decrease of the recognition rate was observed when the delay is over ±8 frames, which indicates that visual information does not improve, or in some conditions, even disturbs the speech recognition. To examine the effect of word order, the same experiment was done using sentences but with a different word order. Subject performed best when presented with the order used in news reading i.e., time location subject object verb, and recognized the subject word more frequently than any others in all conditions. It is interesting that the time range of visual-facilitation is comparable with the time range of audiovisual simultaneity reported in psychophysical studies.

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We have been conducting research with the objective of achieving three-dimensional (3D) television using integral photography. Extremely high-resolution (EHR) elemental images are necessary to enhance integral 3D image quality. Presently, projection display systems are practical for displaying EHR images and have some advantages for 3D imaging. However, any geometric distortion of the projection lens will cause a positional error between the elemental images and elemental lenses. This positional error subsequently results in a distortion of the reconstructed image and a smaller viewing area. We theoretically and experimentally analyzed the effects of distorted elemental images on a reconstructed image. As a result, a slight distortion of the projection lens, which is proportional to the square of the image height, caused a positional error of the reconstructed 3D image. The depth-direction error of the reconstructed image was larger than that of the lateral direction. Furthermore, the viewing area decreased due to the distortion of the elemental images. From experimental results using a projection-type integral system, we found that image processing for distortion compensation is effective in eliminating distortion and improving the viewing area of the reconstructed 3D image.

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Visitors cannot always view objects displayed in the cases in most museums as well as desired because of light reflecting from the glass. Not only their fade color but also highlights of the glass in the showcases make studying them in detail difficult. We present an overlapped multi-projection display system for creating a high-color appearance onto the surface of an object. Our system can also be used to compensate for the distortion caused by the reflection. Such as system is suitable for compensating for the distortion caused by the maximum color and brightness of images presented with conventional projectors. To reduce the loss of quality caused by the highlights, each projector automatically excludes the specular direction area, and then another projector complements the exclusion. Using this combined approach expands the range of the colors that can be reproduced and reduces the detrimental effect of the brighter area. We introduce overlapped multi-projection and show experimental results for when the appearance of the color of regular gradation patterns was changed and the appearance of a painting that had naturally degraded. Our method can be applied to all types of projection onto screens that do not have a matt surface.

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HARP (High-gain Avalanche Rushing amorphous Photoconductor) photoconductive films have high sensitivity by means of avalanche multiplication in amorphous selenium (a-Se) . A 15-μm-thick HARP photoconductive film that has a photoelectric-conversion efficiency for red light that is twice that of the conventional one has been developed. The HARP film, which mainly consists of a-Se with a band gap of about 2.0 eV, does not have sufficient photoelectric-conversion efficiency for red light. To solve this problem, the film is doped with Te with a band gap of about 0.3 eV. Doping a-Se with a larger amount of Te increases the efficiency. However, it can also deteriorate characteristics such as dark current, defect occurrence, and lag, because it creates many trap levels for electrons in the Te-doped a-Se layer. Trapped electrons increase the internal electric field around the incidentlight-side interface. We investigated Te-doping conditions that would not cause these problems.

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This paper presents a dynamic range expansion technique for CMOS image sensors using dual charge storage in a pixel and multiple exposures. Each pixel contains two photodiodes, PD1 and PD2 whose sensitivity can be set independently by the accumulation time. The difference of charge accumulation time in both photodiodes can be widely controlled to expand the dynamic range of the sensor. It allows flexible control of the dynamic range since the accumulation time in the PD2 signal is adjustable. The multiple exposure technique used in the sensor reduces the motion blur in the synthesized wide dynamic range image when capturing fast-moving objects. It also reduces the signal-to-noise ratio dip at the switching point of the PD1 signal to the PD2 signals in the synthesized wide dynamic range image. To reduce the read out time, a comparator-controlled selective readout of the PD1 and PD2 signals has been tested. The synthesis of the captured images to produce wide dynamic range image is also described. A wide dynamic range image sensor with 320x240 pixels has been implemented and tested. It is found that the use of 4 exposures in one frame for the short accumulation time signals is sufficient for the reduction of motion blur in the synthesized wide dynamic range image, and the signal-to-noise ratio dipping at the switching point of the PD1 to PD2 signals is reduced by 6 dB using 4 short-time exposures.

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We propose the use of a fast algorithm for estimating background models. This algorithm makes use of Parzen density estimation in non-stationary scenes. Each pixel has a probability density function this is used to approximate the value of pixels observed in a video sequence. Estimating this function quickly and accurately is important. In our approach, theprobability density function is partially updated within the range of a window function based on the value observed. The model quickly adapts to changes in the scene and foreground objects can be robustly detected. Several experiments show the effectiveness of our approach.

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By subjective assessment, this paper investigates the effects of group (or inter-destination) synchro-nization control in multipoint communications where users have a conversation with each other by using voice and video. The results of our assessment show that the fairness among the users can be kept high by using the group synchronization control in networked competitive work. We also demonstrate that the synchronization qual-ity of networked collaborative work in which the interactivity is not so important can be improved by using the group synchronization control. However, the group synchronization control deteriorates the easiness of networked collaborative work in which the interactivity is important.

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We propose the use of a sketch image retrieval system that uses global and local features. These features are extracted on the basis of the relative position of the edge pixel as the global feature and higher order local autocorrelation(HLAC) as the local feature. Experimental results of applying this method to 6,500 images in a Corel photo gallery showed that this method performed well.

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We describe a method of using computer graphics to represent the flow of a river in real-time. As rivers are usually narrow and long, the water surface can be seen in detail only in the near view, but it cannot be seen as clearly from a distance. Therefore, the level of water wave model should be dynamically changed on the basis of the distance from the viewpoint. In the near view, the water wave and the reflection at the riverbank can be seen, but this is impossible from the far view. However, the changes in direction of the wave caused by wind can be seen even in the far view. We also propose a method of generating patterns of waves caused by wind. We applied our method to simulations of a landscape and clarified the behavior of a river in real-time.

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