A Study on Object Pose and Location Estimation by Computer Vision Techniques Using Circular Shape Information for Vehicle Automation and Virtual Reality Applications

• Main Authors: Chih-Chiun Lai, 賴志群
• Other Authors: Wen-Hsiang Tsai
• Format: Others
• Language: en_US
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/39002726804286091654

博士 === 國立交通大學 === 資訊科學系 === 90 === In the field of computer vision, one of the basic and important problems is object pose and location estimation. This kind of problem means to determine the relative position and orientation between a camera and a certain feature such as a point, a line, or a curve detected on an object. Among various kinds of features, circles are very popular in the man-made environments. In this study, one purpose is to explore feasible and effective object location approaches by using combinations of features of circles and lines. Another purpose is to create new computer vision applications, in which the features of lines and circles are utilized to solve the problem of object pose and location estimation. Four methods for object pose and localization of circles are proposed in this study. Then, their applications are discussed, including moving vehicle localization, moving vehicle trajectory prediction, automatic rotorcraft landing, and camera calibration with respect to a computer monitor for virtual reality applications. An approach to estimation of moving lateral vehicle locations for driving assistance using one-wheel shape information in single 2D vehicle images by 3D computer vision techniques is proposed. There are still very few studies on the detection and localization of lateral vehicles. In this study, the wheel shape information of the lateral vehicle is employed to locate the lateral vehicle, in which the wheel information comes from images captured with a camera mounted on the driver’s vehicle. Then, the trajectory of the moving lateral vehicle is predicted by using the temporal information of single wheel shapes in consecutive image pairs. In addition, another approach to estimation of lateral moving vehicle locations and prediction of their trajectories for driving assistance using two-wheel shape information in single 2D images by 3D computer vision techniques is also proposed. The radius of a wheel need not be known in advance. No special mark on the vehicle is required. The 3D relative positions of the contact points of wheels and ground with respect to the camera are obtained by the back-projection principle as the desired relative location of a lateral vehicle. Then, the trajectory of a lateral vehicle is predicted from the spatial information obtained in single images Automatic landing system can alleviate heavy burdens on aircraft pilots. In this study, a new hierarchical approach to landmark localization by computer vision techniques is proposed. Most of the existing related vision-based methods for aircraft landing consider only a situation, in which the entire landmark is in the field of view of the camera. The proposed method instead achieves aircraft location estimation by four hierarchical stages according to the aircraft flight altitudes. In different stages, the features of different parts of the landmark are utilized to estimate the landmark location. Finally, a new approach to camera calibration with respect to a computer monitor is proposed. The camera location parameters, including three position parameters and three orientation ones, obtained from the proposed calibration method are useful for many virtual reality applications in which a camera is mounted on or located near the monitor to “look at” a user in front of the monitor. The calibration problem is solved indirectly by introducing an auxiliary tool, a pair of specially-designed eye-glasses, with a laser pointer mounted on the nosepiece between the two glass frames. Three applications of the proposed method, namely, VR scene display, cursor control by the head direction, and face view rectification for preserving eye contact in video conferencing or Internet telephony, are also discussed, with their respective mathematics derived in detail. Experiments have also been conducted with good results to prove the correctness of the derived equations and the feasibility of all the proposed approaches.