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[Author] Takeshi YOSHITOME(8hit)

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  • Image Retargeting with Protection of Object Arrangement

    Kazu MISHIBA  Takeshi YOSHITOME  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E97-D No:6
      Page(s):
    1583-1589

    The relative arrangement, such as relative positions and orientations among objects, can play an important role in expressing the situation such as sports games and race scenes. In this paper, we propose a retargeting method that allows maintaining the relative arrangement. Our proposed retargeting method is based on a warping method which finds an optimal transformation by solving an energy minimization problem. To achieve protection of object arrangement, we introduce an energy that enforces all the objects and the relative positions among these objects to be transformed by the same transformation in the retargeting process. In addition, our method imposes the following three types of conditions in order to obtain more satisfactory results: protection of important regions, avoiding extreme deformation, and cropping with preservation of the balance of visual importance. Experimental results demonstrate that our proposed method maintains the relative arrangement while protecting important regions.

  • Three-Layer Cooperative Architecture for MPEG-2 Video Encoder LSI

    Mitsuo IKEDA  Toshio KONDO  Koyo NITTA  Kazuhito SUGURI  Takeshi YOSHITOME  Toshihiro MINAMI  Jiro NAGANUMA  Takeshi OGURA  

     
    PAPER

      Vol:
    E83-C No:2
      Page(s):
    170-178

    This paper presents an architecture for a single-chip MPEG-2 video encoder and demonstrates its flexibility and usefulness. The architecture based on three-layer cooperation provides flexible data-transfer that improves the encoder from the standpoints of versatility, scalability, and video quality. The LSI was successfully fabricated in the 0.25-µm four-metal CMOS process. Its small size and its low power consumption make it ideal for a wide range of applications, such as DVD recorders, PC-card encoders and HDTV encoders.

  • A Distributed Stream Multiplexing Architecture for Multi-Chip Configuration beyond HDTV

    Takayuki ONISHI  Ken NAKAMURA  Takeshi YOSHITOME  Jiro NAGANUMA  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E91-D No:12
      Page(s):
    2862-2867

    This paper proposes a distributed stream multiplexing architecture for video codec LSIs with multi-chip configuration. This distributed architecture utilizes a built-in media multiplexing unit with an external stream input and inter-chip communication interfaces. Parallel protocol processing, with an autonomous inter-chip control mechanism to mix and concatenate packets through daisy-chained transfer paths, provides a complete multi-chip stream output at the end of the chain. Dispensing with external post-processing devices contributes to both high throughput and downsizing of high-end video codec systems. It is configurable for parallel encoding of super high-resolution video, multi-view/-angled HDTV vision and multiple HDTV programs. The architecture was successfully implemented in a fabricated single-chip MPEG-2 422P@HL codec LSI and utilized for the development of a super high-resolution video codec system.

  • Improvement of Colorization-Based Coding Using Optimization by Novel Colorization Matrix Construction and Adaptive Color Conversion

    Kazu MISHIBA  Takeshi YOSHITOME  

     
    PAPER-Image Processing and Video Processing

      Pubricized:
    2015/07/31
      Vol:
    E98-D No:11
      Page(s):
    1943-1949

    This study improves the compression efficiency of Lee's colorization-based coding framework by introducing a novel colorization matrix construction and an adaptive color conversion. Colorization-based coding methods reconstruct color components in the decoder by colorization, which adds color to a base component (a grayscale image) using scant color information. The colorization process can be expressed as a linear combination of a few column vectors of a colorization matrix. Thus it is important for colorization-based coding to make a colorization matrix whose column vectors effectively approximate color components. To make a colorization matrix, Lee's colorization-based coding framework first obtains a base and color components by RGB-YCbCr color conversion, and then performs a segmentation method on the base component. Finally, the entries of a colorization matrix are created using the segmentation results. To improve compression efficiency on this framework, we construct a colorization matrix based on a correlation of base-color components. Furthermore, we embed an edge-preserving smoothing filtering process into the colorization matrix to reduce artifacts. To achieve more improvement, our method uses adaptive color conversion instead of RGB-YCbCr color conversion. Our proposed color conversion maximizes the sum of the local variance of a base component, which resulted in increment of the difference of intensities at region boundaries. Since segmentation methods partition images based on the difference, our adaptive color conversion leads to better segmentation results. Experiments showed that our method has higher compression efficiency compared with the conventional method.

  • Improved Seam Merging for Content-Aware Image Resizing

    Kazu MISHIBA  Masaaki IKEHARA  Takeshi YOSHITOME  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E96-D No:2
      Page(s):
    349-356

    In this paper, we propose an improved seam merging method for content-aware image resizing. This method merges a two-pixel-width seam element into one new pixel in image reduction and inserts a new pixel between the two pixels in image enlargement. To preserve important contents and structure, our method uses energy terms associated with importance and structure. Our method preserve the main structures by using a cartoon version of the original image when calculating the structure energy. In addition, we introduce a new energy term to suppress the distortion generated by excessive reduction or enlargement in iterated merger or insertion. Experimental results demonstrate that the proposed method can produce satisfactory results in both image reduction and enlargement.

  • A Flexible Video CODEC System for Super High Resolution Video

    Takeshi YOSHITOME  Ken NAKAMURA  Jiro NAGANUMA  Yoshiyuki YASHIMA  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E91-D No:11
      Page(s):
    2709-2717

    We propose a flexible video CODEC system for super-high-resolution videos such as those utilizing 4k2k pixel. It uses the spatially parallel encoding approach and has sufficient scalability for the target video resolution to be encoded. A video shift and padding function has been introduced to prevent the image quality from being degraded when different active line systems are connected. The switchable cascade multiplexing function of our system enables various super-high-resolutions to be encoded and super-high-resolution video streams to be recorded and played back using a conventional PC. A two-stage encoding method using the complexity of each divided image has been introduced to equalize encoding quality among multiple divided videos. System Time Clock (STC) sharing has also been implemented in this CODEC system to absorb the disparity in the times streams are received between channels. These functions enable highly-efficient, high-quality encoding for super-high-resolution video.

  • Hierarchical Analysis System for VLSI Power Supply Network

    Takeshi YOSHITOME  

     
    PAPER

      Vol:
    E76-A No:10
      Page(s):
    1659-1665

    Since, in a VLSI circuit, the number of transistors and the clock frequency are constantly increasing, it is important to analyze the voltage drop and current density on a full chip's power networks. We propose a new hierarchical power analysis system named XPOWER. A new reduction algorithm for the resistance and current source network is used in this system. The algorithm utilizes the design hierarchy in nature and is independent of network topology. Networks at each level are reduced into small and equivalent networks, and this reduction is performed recursively from the bottom levels of the design hierarchy. At each step of the reduction, the network under consideration consists of two kinds of objects: (1) reduced child networks, and (2) the interconnection between child networks. After all networks have been reduced, circuit equationa are solved recursively from the top. This allows to decrease the size of the matrix to be solved and to reduce the execution time. Experimental results show that the factor of reduction in matrix size is from 1/10 to 1/40 and execution is six times faster than with flat analysis. The power networks of a 16 bit digital signal processor was analyzed within 15 minutes using XPOWER.

  • Content Aware Image Resizing with Constraint of Object Aspect Ratio Preservation

    Kazu MISHIBA  Masaaki IKEHARA  Takeshi YOSHITOME  

     
    PAPER-Image Processing and Video Processing

      Vol:
    E96-D No:11
      Page(s):
    2427-2436

    In this paper, we propose a novel content-aware image resizing method based on grid transformation. Our method focuses on not only keeping important regions unchanged but also keeping the aspect ratio of the main object in an image unchanged. The dual conditions can avoid distortion which often occurs when only using the former condition. Our method first calculates image importance. Next, we extract the main objects on an image by using image importance. Finally, we calculate the optimal grid transformation which suppresses changes in size of important regions and in the aspect ratios of the main objects. Our method uses lower and upper thresholds for transformation to suppress distortion due to extreme shrinking and enlargement. To achieve better resizing results, we introduce a boundary discarding process. This process can assign wider regions to important regions, reducing distortions on important regions. Experimental results demonstrate that our proposed method resizes images with less distortion than other resizing methods.