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[Author] Akihiro MORI(5hit)

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  • Fast Image Mosaicing Based on Histograms

    Akihiro MORI  Seiichi UCHIDA  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E91-D No:11
      Page(s):
    2701-2708

    This paper introduces a fast image mosaicing technique that does not require costly search on image domain (e.g., pixel-to-pixel correspondence search on the image domain) and the iterative optimization (e.g., gradient-based optimization, iterative optimization, and random optimization) of geometric transformation parameter. The proposed technique is organized in a two-step manner. At both steps, histograms are fully utilized for high computational efficiency. At the first step, a histogram of pixel feature values is utilized to detect pairs of pixels with the same rare feature values as candidates of corresponding pixel pairs. At the second step, a histogram of transformation parameter values is utilized to determine the most reliable transformation parameter value. Experimental results showed that the proposed technique can provide reasonable mosaicing results in most cases with very feasible computations.

  • FM Laser Operation of a Ti:Sapphire Laser

    Akihiro MORIMOTO  Tadao OKIMOTO  Akira SOGA  Tetsuro KOBAYASHI  

     
    LETTER

      Vol:
    E78-C No:1
      Page(s):
    88-90

    FM laser operation of a Ti:sapphire laser is studied experimentally for the first time with an internal phase modulator. We obtained extremely wide FM sidebands of 8 THz width whose phase modulation index was 25,000 rad at a modulation frequency of 160 MHz.

  • Generation of Flat Optical Frequency Comb Based on FM Laser Operation of Fiber Ring Laser

    Masaki HIRANO  Ryosuke YOTSUTANI  Akihiro MORIMOTO  

     
    LETTER-Lasers, Quantum Electronics

      Vol:
    E94-C No:1
      Page(s):
    132-133

    We obtained flat optical frequency combs by using the FM laser operation of a fiber ring laser and external intensity modulation. Extremely wide FM spectra can be easily obtained by the moderate internal phase modulation of an FM laser. We used an external intensity modulator to extract a linearly chirped part from the FM light in order to obtain flat spectra. In our experiments, we obtained a flat optical frequency comb with a spectral bandwidth of about 0.5 THz and a power deviation of less than 1.5 dB.

  • Analysis of High-Speed Signal Behavior in a Miniaturized Interconnect

    Akihiro MORIMOTO  Koji KOTANI  Kazushi TAKAHASHI  Shigetoshi SUGAWA  Tadahiro OHMI  

     
    PAPER

      Vol:
    E85-C No:5
      Page(s):
    1111-1118

    Precise interconnect analysis is strongly required for giga-scale integration the operation frequency of which is excess 10 GHz. In this study, detailed and accurate analyses of a coaxial interconnect and an actual rectangular interconnect have been performed by the direct evaluation of Maxwell's equations and the finite element method, respectively. It has been revealed that there are two propagation modes for LSI interconnects: skin depth limited propagation mode and interconnect induced slow wave mode. In a miniaturized interconnect, the propagation mode is the interconnect induced slow wave mode; therefore, we cannot obtain the light-speed propagation due to such an interconnect-induced effect. In order to overcome this speed limitation or to improve signal integrity, it is essential to introduce a short interconnect for a miniaturized structure, and a much larger interconnect than the skin depth. We propose a gas-isolated interconnect as a candidate for an ultimately low-k structure in order to increase the signal-propagation speed. By the introduction of such structures, the performance of miniaturized devices in the deep submicron region will be effectively enhanced.

  • Ultrashort Optical Pulse Shaping by Electrooptic Synthesizer

    Dae-Sik KIM  Tattee KHAYIM  Akihiro MORIMOTO  Tetsuro KOBAYASHI  

     
    LETTER

      Vol:
    E81-C No:2
      Page(s):
    260-263

    We demonstrate an electrooptic synthesis technique for generating arbitrarily shaped short optical pulses from a CW narrow linewidth laser. For the optical pulse shaping, a large-amplitude electrooptic phase modulator is specially fabricated by employing the quasi-velocity-matching. The phase modulated light having sidebands as wide as 1 THz is separated and phase-only-controlled spatially by a liquid crystal modulator array. After composing the light by using a grating, nearly 1. 2 ps of Fourier-transform-limited optical pulses is obtained.