Zhihu Chen

Publications (8)6.08 Total impact

• Article: A Stratified Approach for Camera Calibration Using Spheres

  K.-Y.K. Wong, Guoqiang Zhang, Zhihu Chen
  [show abstract] [hide abstract]
  ABSTRACT: This paper proposes a stratified approach for camera calibration using spheres. Previous works have exploited epipolar tangents to locate frontier points on spheres for estimating the epipolar geometry. It is shown in this paper that other than the frontier points, two additional point features can be obtained by considering the bitangent envelopes of a pair of spheres. A simple method for locating the images of such point features and the sphere centers is presented. An algorithm for recovering the fundamental matrix in a plane plus parallax representation using these recovered image points and the epipolar tangents from three spheres is developed. A new formulation of the absolute dual quadric as a cone tangent to a dual sphere with the plane at infinity being its vertex is derived. This allows the recovery of the absolute dual quadric, which is used to upgrade the weak calibration to a full calibration. Experimental results on both synthetic and real data are presented, which demonstrate the feasibility and the high precision achieved by our proposed algorithm.
  IEEE Transactions on Image Processing 03/2011; · 3.04 Impact Factor
• Source

  Available from: hku.hk

  Article: A stratified approach for camera calibration using spheres.

  Kwan-Yee Kenneth Wong, Guoqiang Zhang, Zhihu Chen
  [show abstract] [hide abstract]
  ABSTRACT: This paper proposes a stratified approach for camera calibration using spheres. Previous works have exploited epipolar tangents to locate frontier points on spheres for estimating the epipolar geometry. It is shown in this paper that other than the frontier points, two additional point features can be obtained by considering the bitangent envelopes of a pair of spheres. A simple method for locating the images of such point features and the sphere centers is presented. An algorithm for recovering the fundamental matrix in a plane plus parallax representation using these recovered image points and the epipolar tangents from three spheres is developed. A new formulation of the absolute dual quadric as a cone tangent to a dual sphere with the plane at infinity being its vertex is derived. This allows the recovery of the absolute dual quadric, which is used to upgrade the weak calibration to a full calibration. Experimental results on both synthetic and real data are presented, which demonstrate the feasibility and the high precision achieved by our proposed algorithm.
  IEEE Transactions on Image Processing 02/2011; 20(2):305-16. · 3.04 Impact Factor
• Conference Proceeding: Pose estimation from reflections for specular surface recovery.

  Miaomiao Liu, Kwan-Yee Kenneth Wong, Zhenwen Dai, Zhihu Chen
  IEEE International Conference on Computer Vision, ICCV 2011, Barcelona, Spain, November 6-13, 2011; 01/2011
• Conference Proceeding: Robust and Unbiased Foreground / Background Energy for Multi-view Stereo.

  Zhihu Chen, Kwan-Yee Kenneth Wong
  VISAPP 2011 - Proceedings of the Sixth International Conference on Computer Vision Theory and Applications, Vilamoura, Algarve, Portugal, 5-7 March, 2011; 01/2011
• Article: A Stratified Approach for Camera Calibration Using Spheres.

  Kwan-Yee Kenneth Wong, Guoqiang Zhang, Zhihu Chen
  IEEE Transactions on Image Processing. 01/2011; 20:305-316.
• Conference Proceeding: Self-calibrating depth from refraction.

  Zhihu Chen, Kwan-Yee Kenneth Wong, Yasuyuki Matsushita, Xiaolong Zhu, Miaomiao Liu
  IEEE International Conference on Computer Vision, ICCV 2011, Barcelona, Spain, November 6-13, 2011; 01/2011
• Source

  Available from: hku.hk

  Conference Proceeding: Single-view reconstruction from an unknown spherical mirror.

  Zhihu Chen, Kwan-Yee Kenneth Wong, Miaomiao Liu, Dirk Schnieders
  18th IEEE International Conference on Image Processing, ICIP 2011, Brussels, Belgium, September 11-14, 2011; 01/2011
• Conference Proceeding: Specular Surface Recovery from Reflections of a Planar Pattern Undergoing an Unknown Pure Translation.

  Miaomiao Liu, Kwan-Yee Kenneth Wong, Zhenwen Dai, Zhihu Chen
  Computer Vision - ACCV 2010 - 10th Asian Conference on Computer Vision, Queenstown, New Zealand, November 8-12, 2010, Revised Selected Papers, Part II; 01/2010