Traffic behavior surveys by hand require both a lot of money and human resources. Recently, traffic behavior surveys using information technology have been carried out. In this study, we propose a method to extract staying points from GPS-based positional data and identify the types of staying facilities by using Google Places API, a facility ontology, the regularity which is analyzed from trip chains about traffic behavior. This method could identify 68.5% types of staying facilities correctly in the evaluation using GPS location data from the Traffic Behavior Survey in Nagasaki.

Motion-compensated (MC) prediction is one of the most effective coding tools for high-compression video coding. In former works, adaptive interpolation filter (AIF) technology, which improves the coding performance of the fractional-pel MC, has been proposed. As for the real-time codec system, the implementation of AIF based on the Wiener filter algorithm is difficult because of its high computational complexity. To overcome this problem, in this paper, we propose a low-complexity AIF scheme, which can maintain the coding performance achieved by the conventional AIF. The key technology is the efficient filter design process based on the amplitude characteristic analysis with the precise estimation of MC error signal. The experimental result confirmed that almost the same coding performance was maintained at only 30% of the complexity compared to the conventional AIF.

To improve high resolution video coding efficiency under low bit-rate condition, an appropriate coding mode is required from an R-D optimization (RDO) perspective, although a coding mode defined within the H.264 standard is not always optimal for RDO criteria. With this in mind, we previously proposed extended SKIP modes with close-to-optimal R-D characteristics. However, the additional modes did not always satisfy the optimal R-D characteristics, especially for low bit-rate coding. In this paper, we propose an enhanced coding mode capable of providing a candidate corresponding to the minimum R-D cost by controlling the residual signal associated with the extended SKIP mode. The experimental result showed that the PSNR improvement against H.264 and our previous approach reached 0.42 dB and 0.24 dB in the maximum case, respectively.

Digital terrestrial broadcasting in Japan specifies a service profile not only for fixed receivers in the home, but also for personal mobile terminals such as acellular phones and PDAs. Services for personal mobile terminals are expected to become more attractive with sufficient functionality and flexibility by utilizing the network connectivity of mobile terminals. In order to verify the possibilities of digital television broadcasting (DTV) services for personal mobile terminals and clarify technical problems at the commercial level, we developed a prototype mobile terminal capable of receiving digital terrestrial broadcasting in addition to the Internet. This paper describes the assumed DTV service for personal mobile terminals and the technical architecture of the developed mobile terminal with regard to the hardware and the software. Several experiments using the developed mobile terminal were conducted and the performance was evaluated.

For contribution and primary distribution of television, i.e., television transmission to broadcasting stations, parallel transmission links that include codecs are often set up for reliability. However, this configuration still faces the following issues: 1) during normal periods, the reserve link is totally wasted and 2) when a failure occurs, the disrupted signal continues to be transmitted until the system switches to the reserve link. In addition, in digital video transmission, automatic assessment of received video quality is an important issue. To address these issues, the authors developed a processing system for parallelly transmitted video signals, which mainly consists of the following three elements: 1) when both links are normal, outputting the average signal of both links reduces compression coding noise and improves picture quality compared to only one link (efficiency); 2) comparison of the pictures from the two links enables failure detection in either link, to switch to the normal link (support of failure detection); and 3) comparison of the two normally decoded pictures enables evaluation of picture quality (automatic coding noise evaluation). This unique system improves the reliability and operational efficiency of conventional parallel video transmission links.

Motion JPEG2000 has been developed as a new video coding standard for motion pictures, utilizing the still image coding standard JPEG2000. Motion JPEG2000 specifies a normative bitstream syntax that the decoder must recognize and allows flexible selection of detailed coding parameters at the encoder. The compression performance largely depends, therefore, on the encoder design. However, the simple implementation of JPEG2000 encoder might cause picture quality degradation due specifically to wavelet image coding of interlaced TV signals and unsatisfactory bit assignments. That degradation might then become conspicuous in subjective picture quality especially during low bit-rate coding. To overcome this problem, we investigated an optimal design for a Motion JPEG2000 encoder that can be used for primary distribution applications of HDTV programs, assuming that the available bit-rate is approximately 50 Mbps. Our study introduces advanced key technologies not yet recognized officially. Coding experiments using those technologies confirmed that a significant coding gain was achieved versus conventional encoding schemes.

Presenting images from a free viewpoint is a promising interactive video application. Though reference images from one viewpoint and their depth maps are often used to render free viewpoint images, picture quality degradation may occur because of lack of information in background regions that are occluded by foreground regions. In this paper an interpolation method for free viewpoint images using multilayered dynamic background buffers is proposed. In the proposed method, the buffers, updated using the reference images divided in each frame, are used to store the background regions and the output images are interpolated by the background buffers. Since the background buffers are created and updated using only the reference images and their depth maps, additional information on the background buffers is not required for the interpolation. The effectiveness of the proposed method was evaluated by several simulation experiments.

MPEG-2 is an international standard specifying a normative bitstream syntax that decoders must recognize and that allows flexible selection of detailed coding parameters at the encoder. The compression performance is therefore largely dependent on the encoder design and the difference in coded picture quality is present even among encoders developed by different codec makers at identical bit-rates. Conventional MPEG-2 encoders were also designed for high picture quality transmission at an adequate bit-rate, and the overhead portion occupancy in a coded bitstream can be ignored in the final picture quality. However, the unexpected increase in overhead portion occupancy might cause fatal picture quality degradation at extremely low bitrates. To overcome this problem, we investigated an optimal design for an MPEG-2 encoder for use in HDTV digital terrestrial broadcasting where the available bit-rate is limited to less than 0.2 bit/pixel. In our study, advanced key technologies which have not been clearly recognized until now were introduced into possible optimization points, picture type selection macroblock coding mode selection and rate control, and a significant coding gain versus conventional encoding schemes was confirmed in coding experiments.

To realize practical orbital servicing missions in the 21/sup st/ century, we have developed a new system concept for an orbital servicing vehicle named Hyper-OSV (Orbital Servicing Vehicle), which has higher speed manipulation capability and larger operation area than OSVs that were proposed in the 1990's. The main feature of Hyper-OSV (HOSV) is the separation of the operation function and the long-term in-orbit surviving functions such as a solar panel and a large communication antenna. This releases HOSV from attitude restrictions and flexible dynamics and provides a large operation area. The second feature of HOSV is the reconfigurable function that allows HOSV to perform various orbital servicing missions. One of the most difficult missions of HOSV is the noncooperative satellite capture. Separation of the operation function and the long-term in-orbit survival functions gives HOSV an agile working ability. Thus, we have proposed a satellite capturing strategy using an agile orbital servicing vehicle like HOSV and have been conducting its feasibility study. This paper outlines Hyper-OSV first, and then presents the satellite capturing strategy using an agile orbital servicing vehicle and feasibility studies of the satellite capturing.

The conventional full-redundant duplicate transmission scheme, which is often adopted in video transmission that requires high reliability such as contribution and primary distribution, has a drawback in that the efficiency of utilization of transmission links is low. In order to improve this, it would be effective to realize "flat multi-scalable video transmission", in which the picture can be reconstructed by using any single channel, while combining more than one channel leads to the reconstruction of the picture with even higher quality. In this paper, for this purpose, the authors propose a "complementary sampling method". In this method, the improvement in picture quality is achieved by cancelling out the coding noise which is included in more than one channel. Moreover, it is shown that in this scheme, the objective assessment of picture quality can be performed based only on the received pictures. The authors hope that this study will help to construct a visual communication system with high efficiency and high reliability.

This paper describes advanced rate control technologies suitable for the digital compression coding based on MPEG-2 multi-view profile for transmitting three dimensional stereo HDTV signals at bit-rates 45 Mbps for PDH networks or 52 Mbps for SDH networks. First of all, a common buffer control is introduced, which achieves statistical multiplexing effect while keeping the picture qualify of both the left and right pictures well balanced. Under the assumption of applying this common buffer control, we investigate the optimal setting of GOP structure which has a close relation with the rate control. And then, a discriminatory bit allocation is proposed which improves the left picture quality without any degradation of the right picture. From the results of coding experiment conducted to evaluate the coding picture achieved by this coding scheme, it is confined that our coding scheme gives satisfactory picture quality even at 45 Mbps including audio and FEC data.

The motion compensated interframe differential pulse code modulation (DPCM) and discrete cosine transform (DCT) hybrid (MC DCT) coding was nominated as a standard scheme for component TV signals by ISO and ITU-R. However, in cases where an NTSC composite TV signal is used such as the United States and Japan, applying the MC DCT scheme with its luminance/chrominance separating and composing process causes unavoidable quality degradation. The reason for this additional process required for MC DCT is that a composite TV signal presents a "color subcarrier phase shift problem" in which the color subcarrier phase varies between a coding block and reference block according to the motion vector. In this paper, we propose a Walsh Hadamard transform (WHT)-based composite motion compensated NTSC interframe direct coding scheme. In this scheme, phase shifts of a color subcarrier and modulated chrominance components between a coding block and reference block can be effectively compensated by a simple process of coefficient permutation and polarity changes of several pairs of WHT coefficients to which 100% of the subcarrier energy and most of the modulated chrominance component's energy are packed. In the motion compensated DCT scheme, however, the energy of the color subcarrier and modulated chrominance components are spread over too many coefficients and a pair-based coefficient handling rule is not given to solve this problem. This paper demonstrates that the proposed scheme provides higher coding performance for a composite NTSC signal than does the motion compensated DCT scheme with its luminance/chrominance separating and composing process.

This paper describes a 15/30 Mbit/s TV codec with a new approach to high-efficiency coding for TV signals, i.e., median adaptive prediction. The 15/30 Mbit/s codec, commonly applicable to NTSC, PAL, and SECAM (525/60 and 625/50) systems, uses adaptive prediction incorporating a motion-compensated interframe, an interfield, and an intrafield predictor. Its performance for digital transmission is presented. This universal codec is designed, based on CCIR recommendations concerning digital TV coding parameters for studios (Rec. 601) and general principles on long-distance digital TV transmission (Rec. 604). A field trial of 15 Mbit/s digital TV transmission using this codec between earth stations with a 30 m diameter antenna and a 5 m diameter antenna is reported.

As a high efficiency coding method for TV signals, variable length coding, such as Huffman coding, is extremely effective. However, when this variable length coding is applied to an actual TV codec which requires high-speed real-time processing, maximum word length will be limited for the hardware configuration. This correspondence describes an algorithm for the construction of a modified Huffman code with limited maximum word length by means of a "top-down" procedure meeting this requirement instead of the conventional "bottom-up" algorithm.