The Journal of The Institute of Image Information and Television Engineers
Online ISSN : 1881-6908
Print ISSN : 1342-6907
ISSN-L : 1342-6907
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Volume 66, Issue 7
Displaying 1-28 of 28 articles from this issue
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  • Performance Improvement of Channel Equalizer for Multipath Outside the Guard Interval of ISDB-T Signals
    Tomoaki Takeuchi, Koichiro Imamura, Hiroyuki Hamazumi, Kazuhiko Shibuy ...
    2012 Volume 66 Issue 7 Pages J196-J206
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J196
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    Most digital terrestrial television broadcasting systems including Integrated Services Digital Broadcasting-Terrestrial (ISDB-T) system use the orthogonal frequency division multiplexing (OFDM) scheme, which is robust against echoes (multipath interference) due to the insertion of a guard interval. However, echoes can occur outside the guard interval and degrade the quality of the received signal, especially in single frequency network (SFN). To overcome this problem, a channel equalizer that performs a Fast Fourier transform (FFT) on several OFDM symbols in combination and then equalizes the frequency characteristics in the frequency domain has been shown to be effective. In this paper, we extend this scheme and propose an equalization algorithm using serially concatenated two-frequency domain equalizers. Simulation results showed that the performance was improved, especially when the delay spread was within the guard interval length. We also added an adaptive control method to the leak process part of the channel estimation. Results of a field experiment in a receiving environment with reflection waves from the mountains further demonstrated the effectiveness of the proposed method.
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  • Algorithm for Vectorizing Measured Drawings of Archaeological Remains
    Nobuyuki Umezu, Shuichi Hasegawa
    2012 Volume 66 Issue 7 Pages J207-J213
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J207
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    We present an algorithm for vectorizing measured drawings of archaeological remains. Since archaeological excavation is essentially a destructive process, measured drawings are one of the most important records. Most of these drawings are first hand-drawn at excavation sites and then archaeologists spend an enormous amount of time clicking several points to convert scanned drawings into digital vector formats. Our raster-vector conversion algorithm will make this process more convenient. The algorithm assumes that a measured drawing has three layers: first, periodical sectional patterns on a sheet of paper; second, connected components of measured archaeological objects, and third, annotations with long lines. Vectorization experiments were done with scanned measured drawings of the archaeological remains at Tel Rekhesh, Israel. The resultant drawings demonstrate that our algorithm can significantly reduce the following process of manual clicking and editing. Future work will include the implementation of a web service to convert raster images into vector drawings and the improvement of the proposed algorithm by using more of these drawings.
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  • Intelligible High-speed Playback Technology Using the Acoustic Features of Speech Prosody
    Atsushi Imai, Naoyuki Tazawa, Yukio Iwahana, Tohru Takagi, Nobumasa Se ...
    2012 Volume 66 Issue 7 Pages J214-J220
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J214
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    We have developed an intelligible high-speed speech rate conversion technology using the acoustic feature quantities that contribute to prosody. In contrast to the conventional method, which plays back accelerated speech at the same uniform rate from the beginning to end, our proposed approach varies the playback rate adaptively on the basis of acoustic detection of the position of an utterance and any fluctuations in a speaker's fundamental frequency (F0) and power. In so doing, we hope to make high-speed playback easier to listen to by providing the listener with a "slowed-down" playback effect. Since this approach converts speech rate using just the acoustic features of audio data, it can be applied to not only Japanese but other languages as well. While the algorithm we developed in this study is optimized for the Japanese language, we aim to implement the proposed approach in a wider array of commercial devices and customize the technology to various languages.
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  • A Two Million Frames Per Second 300kpixel Single Chip Ultra-high-speed Color Camera with Dynamic Range Compensation for Broadcast Use
    Toshiki Arai, Jun Yonai, Kazuya Kitamura, Hiroshi Ohtake, Tetsuya Haya ...
    2012 Volume 66 Issue 7 Pages J221-J226
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J221
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    We successfully developed a two million fps 300kpixel single chip ultra-high-speed color camera with dynamic range compensation. To reduce the drop in the dynamic range, which is dependent on frame rate, dynamic range compensation was developed, which improved the dynamic range at a frame rate of over 700,000 fps. The ultra-high-speed color camera with an ultra-high-speed CCD V6 with Bayer color filter and a driving circuit with dynamic range compensation was developed. In the experiment, a dynamic range of 41.5dB was measured at a frame rate of two million fps, which was an improvement of 4.7dB compared to using the camera without dynamic range compensation.
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  • Support Vector Data Dscription-Based Method for Finding New Benthic Species and Estimating Their Taxonomy Position from Microscopic Images.
    Takashi Hasegawa, Takahiro Ogawa, Hidemi Watanabe, Miki Haseyama
    2012 Volume 66 Issue 7 Pages J240-J250
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J240
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    This paper presents a support vector data description (SVDD)-based method for finding new benthic species from microscopic images and its application to taxonomy position estimation. First, the proposed method generates hyperspheres that represent taxonomic species taxa of known species and enables automatic species classification. Furthermore, weight estimation of visual features based on multiple kernel learning (MKL) is used in this approach to realize automatic weighting of categorical traits that are traditionally determined by taxonomists. Next, based on the traditional taxonomic classification scheme, the proposed method merges the hyperspheres of similar species and generates new hyperspheres that represent ultra-species taxa in higher hierarchies. Then, from the obtained results, a new decision tree, whose nodes are hyperspheres of species taxa and ultra-species taxa, is constructed. By using this decision tree, new benthic species can be found from target samples, and their taxonomic positions can also be estimated.
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  • Identifying Scenes with the Same Person in Video Content on the Basis of Scene Continuity and Face Similarity Measurement
    Tatsunori Hirai, Tomoyasu Nakano, Masataka Goto, Shigeo Morishima
    2012 Volume 66 Issue 7 Pages J251-J259
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J251
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    We present a method that can automatically annotate when and who is appearing in a video stream that is shot in an unstaged condition. Previous face recognition methods were not robust against different shooting conditions, such as those with variable lighting, face directions, and other factors, in a video stream and had difficulties identifying a person and the scenes the person appears in. To overcome such difficulties, our method groups consecutive video frames (scenes) into clusters that each have the same person's face, which we call a “facial-temporal continuum,” and identifies a person by using many video frames in each cluster. In our experiments, accuracy with our method was approximately two or three times higher than a previous method that recognizes a face in each frame.
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  • Performance of ISDB-T HDTV Mobile Reception Using 8-branch Space Diversity with Iterative Decoding
    Yoshikazu Narikiyo, Masahiro Okano, Masayuki Takada
    2012 Volume 66 Issue 7 Pages J260-J266
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J260
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    We are studying how to improve ISDB-T HDTV mobile reception technology. We have proposed a new reception method that has two core technologies. One is 8-branch space diversity reception, and the other is iterative decoding between Viterbi decoding and Reed-Solomon decoding. We describe the computer simulation results and the performance of field experiments on the proposed prototype receiver in the Kanto area. We compared the performance of mobile reception with two reception methods: conventional 4-branch space diversity without iterative decoding and proposed 8-branch space diversity with iterative decoding. Both results show that the proposed method was improved by approximately 6 dB.
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  • Effects of Super Slow Movie on Motion Observation of Javelin Throw
    Tadayoshi Ise, Takeaki Shionome, Shinichi Watabe
    2012 Volume 66 Issue 7 Pages J267-J270
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J267
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    Recently, video footage has been used for motion observation of primary players for sports instruction. In this paper, we analyze motion observation of an expert javelin thrower at several frame rates of attempt movie. We obtained an interview with an expert javelin instructor to investigate the effectiveness of high speed movies on motion observation with frame rates of 30, 60, 120, and 240 fps. As a result, (1) playback times, (2) pause times, (3) fast-forward or rewind times, and (4) playback order were measured. In addition, 57 of the meaningful units for instruction were obtained from the interview analysis. The results also show that the high speed movie is effective for figuring out a player's conscious of bodymotion and setting an agenda to adjust motion in dynamic postures for motor learning. The differences of the tendency of motion observation between each frame rate were also discussed.
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  • Effect of Accommodation on Apparent Distance Specified by Vergence
    Tomoyuki Daijogo, Masahiro Ishii, Masayuki Sato
    2012 Volume 66 Issue 7 Pages J271-J274
    Published: 2012
    Released on J-STAGE: June 25, 2012
    DOIhttps://doi.org/10.3169/itej.66.J271
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    Apparent distance is modulated by accommodation or vergence. There is conflicting evidence about the effect on distance perception when vergence and accommodation are presented simultaneously. In the current study, we investigated whether apparent distance defined by vergence is modulated by changes of accommodation. Subjects observed a dichoptic stimulus that evoked vergence by looking at a fixation target, through concave or convex lenses. This stimulus is called the reference stimulus. Similarly, they observed a target by looking through non-refractive lenses. This stimulus is called the test stimulus. The reference stimulus and the test stimulus appear at different distances if accommodation modulates apparent distance. We examined the point of subjective equality. The subjects changed the apparent distance of the test stimulus by changing the vergence angle of the test stimulus to make them have the same apparent distance. The result showed that apparent distance is modulated by changes of accommodation.
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