Telecommunications Advancement Foundation

A nationwide survey for measuring field strengths at 40 and 60 kHz was carried out in the winter months of 2004 to estimate the service area of the standard frequency and time signals. The data obtained were analyzed in comparison with the resultant field strengths of sky waves and the ground wave which were predicted using a method developed by one of the authors. Good agreement was seen between the measured and predicted field strengths.

Abstract This paper considers a technique for prerecorded TV programs in which captions for the hearing‐impaired are automatically superimposed on the basis of the program VTR and the advance electronic script. A method of detecting the caption presentation timing by detecting the synchronization timing for the speech and captions is described. For broadcast speech on which background sound is superimposed, it is difficult to achieve high detection accuracy by timing detection based only on a phoneme HMM word spotter. Consequently, this paper proposes the following method. For each sentence in the program script, multiple timing candidates are detected by word spotting. The optimal timing for the whole program is selected by using dynamic programming based on three scores (the time‐order in the manuscript, the ratio of the utterance times estimated from the manuscript, and the likelihood of being speech) in addition to the acoustic likelihood. An evaluation experiment was performed on 10 sessions of a documentary program. Assuming tolerable detection errors of 1 and 3 seconds, detection rates of 99.0 and 99.7% were obtained, respectively, indicating that the method is of practical value. © 2004 Wiley Periodicals, Inc. Electron Comm Jpn Pt 3, 87(11): 73–82, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecjc.20121

Color reproduction systems using multispectral imaging techniques make it possible to accurately reproduce the color of the original object under various viewing illuminants. In this paper, a multispectral image compression method for high fidelity color reproduction is proposed in consideration of color degradation. In the proposed method, a spectral transform and a nonlinear quantization designed to reduce colorimetric error are combined with the discrete wavelet transform in JPEG2000. Through the experiments using some 16-band multispectral images, it is confirmed that the proposed method reduces the average and the maximum color differences in L*a*b* color space in comparison with the conventional methods.

Finding the designated video shots from a video stream within a short time is a big issue in multimedia consumer electronic applications. For a large reduction in the time needed to access the desired video shots, a new system for retrieving the specific shots has been built utilizing on-line motion detection with DSP. Specific video shots can be retrieved at a reduced processing time by using DSP because a series of Y signal image frames and motion vectors are generated on-line by newly utilizing the DSP applications. The image frame codes resulting from the retrieval easily pick up only the designated video shots from the video stream.

This paper describes a multimedia database system for distributing industrial product information, characterizing the retrieval of digital images for distributing to each user terminal the product information generated using a sketched image drawn by the customer. The image retrieval was carried out effectively by newly using the Applet and the Servlet Applications to take out industrial product information to the MMI control, with the aid of the Apache and Tomcat so that images of high definition objects could be sent from the image servers to the MMI devices. The system performance was actually tested over IPv4/IPv6 on the Japan Gigabit Networks (JGN).

Using the Pathfinder Plus high-altitude unmanned aerial vehicle, we did a digital broadcasting experiment. In the experiment, Japan's digital terrestrial broadcasting standard, ISDB-T, was used in the UHF band. From an altitude of 20 km, a radio station installed under a Pathfinder Plus wing transmitted the signal. Reception was successful at the ground station even when we used the parameter set that was least robust under poor channel conditions. The receiving power level of the ground station was measured and agreed with the expected value under the assumption of free space propagation.

We propose a new type of optical probe designed to detect magnetic near-fields with high accuracy up to the gigahertz range. The probe head consists of a loop antenna element doubly-loaded with electro-optic crystals. It optically realizes the operation of a conventional doubly-loaded loop probe and requires no metallic cables or hybrid junction. We examined the probe characteristics for magnetic field detection up to 10 GHz. We confirmed that the probe can detect magnetic fields near a microstrip line and suppress the influence of electric fields

A dynamic intelligent hub station (DIH), a hub station that moves autonomously in a wireless home network based on Wireless 1394, is proposed in order to avoid shadowing and interference without troublesome movement of terminals. We evaluate the effect of DIH in the home environment.

On-board antenna is one of key technologies for wireless access systems installed in high altitude platform station (HAPS). Many special requirements are necessary due to the speciality of HAPS. A prototype on-board digital beamformer (DBF) antenna working in the Ka band is introduced. The prototype achieved quick-response space division multiple access (SDMA) and interference suppression. The block diagrams of the antenna, including its configuration and specifications, are illustrated. Relative beamforming algorithms for the antenna, extended maximal-ratio-combining (MRC), are also presented. Experimental calibration, beamforming and direction of arrival (DOA) estimation results, along with the simulated results obtained with the algorithms are given. The results indicate that this type of antenna is worthy of future study and potentially could be developed as a practical product for use as an on -board HAPS antenna.