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[Keyword] motion vector field(3hit)

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  • A Novel Local Smoothness Constrained Side-Information Frame Generator

    Peng WANG  Jia WANG  Songyu YU  Yuye PANG  

     
    LETTER-Coding Theory

      Vol:
    E91-A No:2
      Page(s):
    692-694

    The quality of the Side-information frame (S frame) influences significantly the rate-distortion performance in the Distributed Video Coding (DVC). In this letter, we propose an efficient Side-Information Frame Generator (SIFG). It considers smoothness constraints of both the motion vector field and spatial adjacent pixels. Simulation results show that the proposed techniques provide potential rate-distortion performance advantages. Besides, the fine visual quality of the S frame is obtained.

  • Real Time Feature-Based Facial Tracking Using Lie Algebras

    Akira INOUE  Tom DRUMMOND  Roberto CIPOLLA  

     
    LETTER

      Vol:
    E84-D No:12
      Page(s):
    1733-1738

    We have developed a novel human facial tracking system that operates in real time at a video frame rate without needing any special hardware. The approach is based on the use of Lie algebra, and uses three-dimensional feature points on the targeted human face. It is assumed that the roughly estimated facial model (relative coordinates of the three-dimensional feature points) is known. First, the initial feature positions of the face are determined using a model fitting technique. Then, the tracking is operated by the following sequence: (1) capture the new video frame and render feature points to the image plane; (2) search for new positions of the feature points on the image plane; (3) get the Euclidean matrix from the moving vector and the three-dimensional information for the points; and (4) rotate and translate the feature points by using the Euclidean matrix, and render the new points on the image plane. The key algorithm of this tracker is to estimate the Euclidean matrix by using a least square technique based on Lie algebra. The resulting tracker performed very well on the task of tracking a human face.

  • Left Ventricular Motion Analysis of 4-D SPECT Imaging Using Normal Direction Constraint

    I-Cheng CHANG  Chung-Lin HUANG  Chen-Chang LEIN  Liang-Chih WU  Shin-Hwa YEH  

     
    PAPER

      Vol:
    E77-D No:11
      Page(s):
    1262-1272

    For medical imaging, non-rigid motion analysis of the heart deformability is a nontrivial problem. This paper introduces a new method to analyze the gated SPECT (Single Photon Emission Computed Tomography) imges for 3-D motion information of left ventricular. Our motion estimation method is based on a new concept called normal direction constraint" in that the normal of a surface patch of some deforming objects at certain time instant is constant. This paper consists of the following processes: contour extraction, slices interpolation, normal vector field generation, expanding process, motion estimation for producing a 2-D motion vector field, and deprojection for a 3-D motion vector field. In the experiments, we will demonstrate the accuracy of our method in analyzing the 3-D motion field of deforming object.