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[Author] Takahiro YAMAGUCHI(5hit)

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  • Automatic Defect Pattern Detection on LSI Wafers Using Image Processing Techniques

    Kazuyuki MARUO  Tadashi SHIBATA  Takahiro YAMAGUCHI  Masayoshi ICHIKAWA  Tadahiro OHMI  

     
    PAPER-Integrated Electronics

      Vol:
    E82-C No:6
      Page(s):
    1003-1012

    This paper describes a defect detection method which automatically extracts defect information from complicated background LSI patterns. Based on a scanning electron microscope (SEM) image, the defects on the wafer are characterized in terms of their locations, sizes and the shape of defects. For this purpose, two image processing techniques, the Hough transform and wavelet transform, have been employed. Especially, the Hough Transform for circles is applied to non-circular defects for estimating the shapes of defects. By experiments, it has been demonstrated that the system is very effective in defect identification and will be used as an integral part in future automatic defect pattern classification systems.

  • VBR Dynamic Access Control for Wireless ATM

    Riwu JIN  Takahiro YAMAGUCHI  Shinji SUGAWARA  Tetsuya MIKI  Luis LOYOLA  

     
    PAPER-Wireless Communication Technology

      Vol:
    E85-B No:7
      Page(s):
    1247-1256

    This paper presents an efficient scheme for access bandwidth control for VBR (Variable Bit Rate) traffic between radio mobile terminals and their base stations in a WATM (Wireless ATM) network. After introducing the wireless ATM system model, we describe a new algorithm that enables dynamic slot allocation under TDMA/TDD (Time Division Multiple Access/Time Division Duplex) Media Access Control, making use of UPC (Usage Parameter Control) parameters and traffic characteristics. We show more efficient bandwidth utilization with our proposed algorithm, compared to other conventional algorithms. Moreover, we reveal that our algorithm improves cell transmission delays.

  • An MMT-Based Hierarchical Transmission Module for 4K/120fps Temporally Scalable Video

    Yasuhiro MOCHIDA  Takayuki NAKACHI  Takahiro YAMAGUCHI  

     
    PAPER

      Pubricized:
    2020/06/22
      Vol:
    E103-D No:10
      Page(s):
    2059-2066

    High frame rate (HFR) video is attracting strong interest since it is considered as a next step toward providing Ultra-High Definition video service. For instance, the Association of Radio Industries and Businesses (ARIB) standard, the latest broadcasting standard in Japan, defines a 120 fps broadcasting format. The standard stipulates temporally scalable coding and hierarchical transmission by MPEG Media Transport (MMT), in which the base layer and the enhancement layer are transmitted over different paths for flexible distribution. We have developed the first ever MMT transmitter/receiver module for 4K/120fps temporally scalable video. The module is equipped with a newly proposed encapsulation method of temporally scalable bitstreams with correct boundaries. It is also designed to be tolerant to severe network constraints, including packet loss, arrival timing offset, and delay jitter. We conducted a hierarchical transmission experiment for 4K/120fps temporally scalable video. The experiment demonstrated that the MMT module was successfully fabricated and capable of dealing with severe network constraints. Consequently, the module has excellent potential as a means to support HFR video distribution in various network situations.

  • Decoding via Sampling

    Shigeki MIYAKE  Jun MURAMATSU  Takahiro YAMAGUCHI  

     
    PAPER-Coding Theory

      Vol:
    E102-A No:11
      Page(s):
    1512-1523

    We propose a novel decoding algorithm called “sampling decoding”, which is constructed using a Markov Chain Monte Carlo (MCMC) method and implements Maximum a Posteriori Probability decoding in an approximate manner. It is also shown that sampling decoding can be easily extended to universal coding or to be applicable for Markov sources. In simulation experiments comparing the proposed algorithm with the sum-product decoding algorithm, sampling decoding is shown to perform better as sample size increases, although decoding time becomes proportionally longer. The mixing time, which measures how large a sample size is needed for the MCMC process to converge to the limiting distribution, is evaluated for a simple coding matrix construction.

  • An Improvement of PDP Picture Quality by Using a Modified-Binary-Coded Scheme with a 3D Scattering of Motional Artifacts

    Takahiro YAMAGUCHI  Shigeo MIKOSHIBA  

     
    INVITED PAPER

      Vol:
    E80-C No:8
      Page(s):
    1079-1085

    When moving images are displayed on color PDPs, motional artifacts such as disturbances of gray scales and colors are often observed. Reduction of the disturbances is essential in achieving PDPs with acceptable picture quality for TV use. The moving picture quality has been improved by using a modified-binary-coded light-emission-period scheme and a 3dimensional (2D in space and 1D in time) scattering technique. In the 10-sub-field modified-binary-code scheme for 256 gray level expression, sub-field B (of period equivalent to 64) and C (128) of conventional 8-sub-field binary-coded scheme are added and then re-distributed into four sub-fields D (48). The modifiedbinary-coded scheme therefore has the light-emitting-period ratio 1:2:4:8:16:32:48:48:48:48. The maximum period, 128 of the conventional, is reduced to 48. By using the modified-binary-coded scheme, the motional artifacts are reduced significantly, but still perceptible because they appear in forms of continuous lines. In order to make the disturbance less conspicuous, a 3D scattering technique is introduced. The technique has been made possible because of the redundancies of the modified-binary-coded scheme: namely, (1) the position of sub-field-block A (63) can be placed at one of the five positions among four sub-fields D (48), (2) there are various choices when newly assigning one of the four sub-fields D, (3) one can arbitrarily choose whether or not to assign a new sub-field D between the gray levels 48-63, 96-111, 144-160, and 192-207. By randomly selecting one of these emission patterns, the disturbances change their forms from continuous lines to scattered dots. The randomization can be performed at each horizontal line of the display, at each vertical line, at each pixel, of at each TV field. An appreciable improvement of moving picture quality has been realized without influencing the still image.