Ying, Xianghua

Professor

Research Interests: Computer vision, pattern recognition

Office Phone: 86-10-6275 9076

Email: xhying@cis.pku.edu.cn

Ying, Xianghua is a professor in the Department of Computer Science and technology, School of EECS. He obtained his B.Sc. from North China Electric Power University in 1997, and Ph.D. from Chinese Academy of Sciences in 2004 respectively. His research interests include multiple view geometry, camera calibration, 3D reconstruction.

Dr. Ying has published more than 50 research papers, and most of them are published in top-tier conferences and journals, such as TPAMI, IJCV, ICCV, CVPR, and ECCV. He has served in the Technical Program Committee of various international conferences including ICCV, CVPR, ECCV and ICRA.

Dr. Ying has more than ten research projects including NSFC, 973 programs, 863 project, etc. His research achievements are summarized as follows:

1) Vision based interaction: In many intelligent environments such smart rooms, wearable computing and tele-conferencing, conventional mice and keyboards seem not suitable, some intuitive, immersive and cost-efficient interaction devices are developed. The technique proposed can be employed to recover 3D rotation only from a set of parallel lines, therefore, we can use a rectangular parallelepiped, such as a packaging box of a bottle, which can be occluded by hands or other objects very seriously, just left three parallel lines visible which are sufficient to drive a virtual 3D objects rotated in the screen as the box do. Obviously, if there is no occlusion, it is easy to recover the 3D rotation parameters of the box. Though the packaging box is occluded by hands very seriously, but 3D rotation can yet be recovered.

2) Camera calibration using spheres: Spherical objects and vanish points are often used for camera calibration. An occluding contour of a sphere is projected to a conic in the perspective image, and using a moving active camera, the trajectory of a vanishing point in the perspective images is also a conic when the camera is rotated about a fixed 3D axis whereas the translation of the camera is arbitrary. Two linear approaches to the problems are proposed: one based on the geometric interpretation of the relation between image conics and the image of the absolute conic, and the other using the special structure of the problems in algebra. Only three such conics are needed for the two linear approaches, and the minimum number for previous nonlinear optimization methods is also three.

3) Dynamic light field acquisition system: Complex dynamic objects in a novel lighting condition to reproduce realistic environment is a key issue in recent virtual reality, digital entertainment, interactive education, and cultural heritage protection. To build fusion of visual graphics technology and light field acquisition and processing system is very important. Dynamic modeling techniques to capture the real scene are one of visual media to promote the future core technology. Based on dynamic light field acquisition system panoramic camera array and high-speed high-power LED light source, not only to capture the geometry information, texture information, scene and object motion information, but also to obtain information on the ambient light reflection properties, the scene with the surface of the object, the technology of virtual reality, immersive video conferencing, filmed entertainment, stereoscopic video and other fields have wide application.