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[Keyword] high quality(7hit)

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  • Image Quality Improvement for Capsule Endoscopy Based on Compressed Sensing with K-SVD Dictionary Learning

    Yuuki HARADA  Daisuke KANEMOTO  Takahiro INOUE  Osamu MAIDA  Tetsuya HIROSE  

     
    LETTER-Image

      Pubricized:
    2021/10/01
      Vol:
    E105-A No:4
      Page(s):
    743-747

    Reducing the power consumption of capsule endoscopy is essential for its further development. We introduce K-SVD dictionary learning to design a dictionary for sparse coding, and improve reconstruction accuracy of capsule endoscopic images captured using compressed sensing. At a compression ratio of 20%, the proposed method improves image quality by approximately 4.4 dB for the peak signal-to-noise ratio.

  • A Study on MgO-Ta2O5 System Ceramics for Microwave Component Application

    Jae-Sik KIM  Eui-Sun CHOI  Young-Hie LEE  Ki-Won RYU  

     
    PAPER

      Vol:
    E91-C No:5
      Page(s):
    772-775

    In this study, the microwave dielectric properties of the Mg4Ta2O9 and Mg5Ta4O15 ceramics with composition ratio and sintering temperature were investigated and the dielectric resonators with these ceramics were simulated. TiO2 was doped in the Mg4Ta2O9 ceramics for improvement of temperature property. The (1-x)Mg4Ta2O9-xTiO2 and Mg5Ta4O15 ceramics were prepared by solid-state reaction method. According to the X-ray diffraction data, the (1-x)Mg4Ta2O9-xTiO2 ceramics had main phase of the Mg4Ta2O9 and MgTi2O5 peaks were appeared by additions of TiO2. In the Mg5Ta4O15 ceramics, the Mg4Ta2O9 and MgTa2O6 phase were coexisted and Mg5Ta4O15 phase was appeared with increments of sintering temperature. Microwave dielectric properties of (1-x)Mg4Ta2O9-xTiO2 ceramics were affected by MgTi2O5 and TiO2 phase. The quality factor had a little decrement compared to pure Mg4Ta2O9, but there was excellent improvement in TCRF by addition of TiO2. Densifications of the Mg4Ta2O9 and MgTa2O6 and existence of the Mg5Ta4O15 phase had influence on the microwave dielectric properties of the Mg5Ta4O15 ceramics. Dielectric constant, quality factor and TCRF of the (1-x)Mg4Ta2O9-xTiO2 and Mg5Ta4O15 ceramics sintered at 1450 were 11.5622.5, 24980186410 GHz, -36.02+19.72 ppm/ and 8.2, 89473 GHz, -10.91 ppm/, respectively. ADS was used for simulation of DR. The simulated DR with the 0.5Mg4Ta2O9-0.5TiO2 and Mg5Ta4O15 ceramics had the S21 of -35.034 dB at 11.97 GHz and -28.493 dB at 10.50 GHz, respectively.

  • Robust Noise Suppression Algorithm with the Kalman Filter Theory for White and Colored Disturbance

    Nari TANABE  Toshihiro FURUKAWA  Shigeo TSUJII  

     
    PAPER-Digital Signal Processing

      Vol:
    E91-A No:3
      Page(s):
    818-829

    We propose a noise suppression algorithm with the Kalman filter theory. The algorithm aims to achieve robust noise suppression for the additive white and colored disturbance from the canonical state space models with (i) a state equation composed of the speech signal and (ii) an observation equation composed of the speech signal and additive noise. The remarkable features of the proposed algorithm are (1) applied to adaptive white and colored noises where the additive colored noise uses babble noise, (2) realization of high performance noise suppression without sacrificing high quality of the speech signal despite simple noise suppression using only the Kalman filter algorithm, while many conventional methods based on the Kalman filter theory usually perform the noise suppression using the parameter estimation algorithm of AR (auto-regressive) system and the Kalman filter algorithm. We show the effectiveness of the proposed method, which utilizes the Kalman filter theory for the proposed canonical state space model with the colored driving source, using numerical results and subjective evaluation results.

  • Adaptive Modulation System with Punctured Convolutional Code for High Quality Personal Communication Systems

    Hidehiro MATSUOKA  Seiichi SAMPEI  Norihiko MORINAGA  Yukiyoshi KAMIO  

     
    PAPER-Modulation, Demodulation

      Vol:
    E79-B No:3
      Page(s):
    328-334

    This paper proposes an adaptive modulation system with a punctured convolutional code for land mobile communications to achieve high quality, high bit rate, and high spectral efficient data transmission in multipath fading environments. The proposed system adaptively controls the coding rate of the punctured convolutional code, symbol rate, and modulation level according to the instantaneous fading channel conditions. During good channel conditions, the modulation parameters are selected to increase the transmission rate as much as possible with satisfying a certain transmission quality. As channel conditions become worse, lower rate modulation parameters are applied or transmission is stopped. The performances in fading environments are evaluated theoretically and by computer simulations. The results show that the proposed system can realize higher quality transmission without the degradation in average bit rate compared to conventional adaptive modulation systems.

  • A Specific Design Approach for Automotive Microcomputers

    Nobusuke ABE  Shozo SHIROTA  

     
    PAPER

      Vol:
    E76-C No:12
      Page(s):
    1788-1793

    When used for automotive applications, microcomputers have to meet two requirements more demanding than those for general use. One of these requirements is to respond to external events within a time scale of microseconds; the other is the high quality and high reliability necessary for the severe environmental operating conditions and the ambitious market requirements inherent to automotive applications. These needs especially the latter one have been responded to by further elaboration of each basic technology involved in semiconductor manufacturing. At the same time, various logic parts have been built into the microcomputer. This paper deals with several design approaches to the high quality and high reliability objective. First, testability improvement by the logical separation method focusing on the logic simulation model for generating test vectors, which enables us to reduce the time required for test vector development in half. Next, noise suppression methods to gain electromagnetic compatibility (EMC). Then, simplified memory transistor's analysis to evaluate the V/I-characteristics directly via external pins without opening the model seal, removing the passivation and placing a probe needle on the chip. Finally, increased reliability of on-chip EPROM using a special circuit raising the threshold value by approximately 1(V) compared to EPROM's without such a circuit.

  • Conversion of Image Resolutions for High Quality Visual Communication

    Saprangsit MRUETUSATORN  Hirotsugu KINOSHITA  Yoshinori SAKAI  

     
    PAPER-Image Processing, Computer Graphics and Pattern Recognition

      Vol:
    E76-D No:2
      Page(s):
    251-258

    This paper discusses the conversion of spatial resolution (pixel density) and amplitude resolution (levels of brightness) for multilevel images. A source image is sampled by an image scanner or a video camera, and a converted image is printed by a printer with the capability of higher spatial but lower amplitude resolution than the image input device. In the proposed method, the impulse response of the scanner sensor is modeled to obtain pixel values from the convolution of the impulse and the image signal. Discontinuous areas (edge) of the original image are detected locally according to the impulse model and neighbouring pixel values. The edge route is estimated which gives the pixel values for the output resolutions. Comparison of the proposed method with two conventional methods, reciprocal distance weight interpolation and pixel replication, shows higher edge quality for the proposed method.

  • Property of Circular Convolution for Subband Image Coding

    Hitoshi KIYA  Kiyoshi NISHIKAWA  Masahiko SAGAWA  

     
    PAPER-Image Coding and Compression

      Vol:
    E75-A No:7
      Page(s):
    852-860

    One of the problems with subband image coding is the increase in image sizes caused by filtering. To solve this, it has been proposed to process the filtering by transforming input sequence into a periodic one. Then filtering is implemented by circular convolution. Although this technique solves the problem, there are very strong restrictions, i.e., limitation on the filter type and on the filter bank structure. In this paper, development of this technique is presented. Consequently, any type of linear phase FIR filter and any structure of filter bank can be used.