Sharif Digital Repository

Human tracking is one of the most important research topics in computer vision with application in surveillance, crowd analysis, human motion and behavior analysis, and human-computer interaction. Availability of a large number of cameras has caused the need of designing automatic tracking methods. One of the most important challenges in automatic tracking is the occlusion of objects. Several methods have been proposed in the literature to solve this problem. One of the most popular and powerful methods is based on the usage of multiple views of the same scene in a cooperative manner between cameras. The most important challenge in using multiple cameras is the complexity of the tracker in... 

Camera calibration in sport videos has applications such as sport video analysis, insertion of virtual graphical elements, and 3D reconstruction. Our goal in this research is to fully calibrate cameras in soccer match videos. By calibration parameters, we mean the internal and the external camera parameters. We can have a mapping from world coordinates to image coordinates if we have all the calibration parameters. The cameras used in this research are stationary pan-tilt-zoom cameras. The main challenges in camera calibration are noise, blur, bad lighting conditions, lack of useful information image,fast movement of camera and radial distortion. In addition, as another challenge, we assume... 

Determination of the position of an object in the 3D world is one of the most basic preprocessing steps in the field of computer vision. It is used in many practical applications such as video surveillance, human action analysis, and human-computer interaction. For this determination, calibrated cameras are usually used for which the internal and external camera parameters are already known. But, in some real-life applications, a pre-access to the camera is not possible. This thesis studies the homography matrix extraction for determination of the position of soccer players. The pan-tilt-zoom (PTZ) cameras are used. (For a stationary camera, a Homography matrix is obtained once.) To... 

In recent decades, many researchers have focused on inferring camera calibration from soccer videos. This task is usually used to provide more information to the audience by adding graphical elements to the field. Indeed, the problem of inserting graphical elements in sport field videos is the problem of calculating projection matrix in continuous frames with which we can insert graphical elements. Basic challenges in this regard are the lack of information in some frames, bad lighting conditions, noise and blur, quick changes of camera viewpoint and radial distortion. Despite previous methods which aimed to propose an algorithm for a specific region of the field, we have introduced a novel...