ITE Transactions on Media Technology and Applications
Online ISSN : 2186-7364
ISSN-L : 2186-7364
8 巻, 3 号
選択された号の論文の8件中1~8を表示しています
Special Section on Media Engineering and Its Applications
Regular Section
  • Yuichiro Yamashita, Rihito Kuroda, Shigetoshi Sugawa
    2020 年 8 巻 3 号 p. 161-169
    発行日: 2020年
    公開日: 2020/07/01
    ジャーナル フリー

    A preserved-color-pixel (PCP) concept is proposed. The PCP color filter array (CFA) is arranged to construct "PCP pixels". A PCP pixel is surrounded by “buffer pixels” having color filters of the same color spectrum as that of the PCP pixel, so that most of color cross-talk from pixels of different colors are absorbed by the buffer pixels. The color cross-talk components of the buffer-pixel signals are computationally canceled by a proposed non-parametric method called "similarity-based blind cross-talk correction (SBC)," where signals of PCP pixels are used as the ground truth to estimate the signals of buffer-pixels without influence of the cross-talk. The demosaicing of each color planes' images sampled with a PCP-CFA arrangement is implemented by the adaptive normalized convolution (ANC) in conjunction with the proposed "post-convolutional-variation-minimization (PCVM)" algorithm for its cost function. Both SBC and PCVM-ANC are especially useful for image acquisition with a pixel array in a sub-half-micron generation, where its pixel pitch is approximately, or smaller than, 0.5 μm. The concept is verified with image simulation, and its effectiveness is quantified with the slanted-edge based spatial frequency response (SFR) modular transfer function (MTF) method by using the parametric color cross-talk analysis based on proposed "scalable-single-parameter (SSP)" color cross-talk model. The image simulation confirms the color reproductivity, together with the effectiveness of image resolution improvement under the influence of the complication of color cross-talk between pixels and lateral chromatic aberration (LCA) of the taking-lens. The benefit is also verified by peak-signal-to-noise-ratio (PSNR) analysis with simulated images based on a real-world picture, indicating that the proposed concept can maintain PSNR when color crosstalk increases.

  • Satoshi Abe, Takefumi Hiraki, Shogo Fukushima, Takeshi Naemura
    2020 年 8 巻 3 号 p. 170-185
    発行日: 2020年
    公開日: 2020/07/01
    ジャーナル フリー

    Communication between screens and cameras has attracted attention as a ubiquitous information source, motivated by the widespread use of smartphones and the increase of public information screens. The method that encodes data into visible patterns impairs the user's visual experience. Previously, embedding matrix barcodes into images on displays by utilizing imperceptible color vibration was proposed. In this approach, the visual experience is maintained considering that barcodes are imperceptible, and it can be implemented on almost any display and camera. Herein, we describe a sophisticated modulation protocol and restoration procedure whereby device characteristics such as the display's gamma feature and the smartphone's rolling shutter are taken into consideration. Extensive experiments reveal the parameters for the modulation and that this system works under practical situations. In addition, scenarios of potential practical applications and a user study examining imperceptibility of barcodes and usability of the system are presented to illustrate the technological capabilities.

  • Toshiro Nunome
    2020 年 8 巻 3 号 p. 186-194
    発行日: 2020年
    公開日: 2020/07/01
    ジャーナル フリー

    In this paper, we assess subjective QoE (Quality of Experience) and objective application-level QoS (Quality of Service) of video IP transmission with error concealment mechanisms of H.264/AVC and AL-FEC (Application-Level Forward Error Correction) of MMT (MPEG Media Transport), which is an application-level protocol for video transmission. The mutual effect is expected to realize more efficient video streaming from a QoE point of view. The experiment treats two contents, two types of the number of slices per picture frame, and two types of the total bitrate of video and its FEC code. We experiment with several load conditions. We then compare FEC schemes with three code rate values and no FEC scheme. We show from the assessment results that the appropriate code rate for QoE enhancement depends on not only network conditions but also contents.

feedback
Top