Loading...
Search for:
camera-calibration
0.009 seconds
Projection matrix by orthogonal vanishing points
, Article Multimedia Tools and Applications ; Volume 76, Issue 15 , 2017 , Pages 16189-16223 ; 13807501 (ISSN) ; Fouladi, S ; Kasaei, S ; Sharif University of Technology
Springer New York LLC
2017
Abstract
Calculation of camera projection matrix, also called camera calibration, is an essential task in many computer vision and 3D data processing applications. Calculation of projection matrix using vanishing points and vanishing lines is well suited in the literature; where the intersection of parallel lines (in 3D Euclidean space) when projected on the camera image plane (by a perspective transformation) is called vanishing point and the intersection of two vanishing points (in the image plane) is called vanishing line. The aim of this paper is to propose a new formulation for easily computing the projection matrix based on three orthogonal vanishing points. It can also be used to calculate the...
, M.Sc. Thesis Sharif University of Technology ; Sayyadi, Hassan (Supervisor) ; Abbaspour, Madjid (Supervisor)
Abstract
Now a day measuring dimensions plays an important role in industries. Improving the technology of measuring the dimensions, leads to higher quality of production. It is important for industries to have a rapid and accurate dimensions in short time. In this thesis, we worked on measuring dimensions with 3D laser scanner and in the end, the results related to accuracy and speed and efficiency of the system was shown in the thesis
Hand Posture Recognition through Stereo Vision System
, M.Sc. Thesis Sharif University of Technology ; Jahed, Mehran (Supervisor)
Abstract
The mankind has always utilized vision as the most essential tool in evaluating his environment. Currently, one of the most important research areas in computer vision is to characterize a three dimensional object through its features in a natural scene. This task may be conducted through a stereo vision system. The objective of this study is to introduce a quantitative measure in order to evaluate the operation of an automatic recognition system for selected hand postures. A key application of our proposed system is to train a prosthetic hand through surface electromyogram (sEMG) signals. At the onset of this process, the patient conducts a certain posture through application of sEMG...
Calibration of PTZ Cameras from Multiview Soccer Match Videos
, M.Sc. Thesis Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
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...
Extracting Homography Matrix to Determine 3D Position of Soccer Players
, Ph.D. Dissertation Sharif University of Technology ; Kasaei, Shohreh (Supervisor)
Abstract
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...
3D Reconstruction and Extrinsic Parameters Calibration of Non-Overlapping Cameras
, M.Sc. Thesis Sharif University of Technology ; Razvan, Mohammad Reza (Supervisor) ; Moghadasi, Reza (Co-Supervisor) ; Kamali Tabrizi, Mostafa (Co-Supervisor)
Abstract
Non-overlapping Cameras in multi-camera systems have become prevalent in robotics and computer vision research; therefore, it is possible to cover the wide field of view, and researches have been done for computing extrinsic parameters of cameras. These cameras do not have any overlap in their views, so obtaining the corresponding point in their images is somehow impossible. Light and shadow geometry is analogous to Structure from Motion problem. In this thesis,we study Structure from Motion problem and have tried to propose an approach for estimating extrinsic parameters of non-overlapping cameras in Multi-camera systems. We formulate the problem by using light and shadow geometry and...
Projection matrix by orthogonal vanishing points
, Article Multimedia Tools and Applications ; 2016 , Pages 1-35 ; 13807501 (ISSN) ; Fouladi, S ; Kasaei, Sh ; Sharif University of Technology
Springer New York LLC
Abstract
Calculation of camera projection matrix, also called camera calibration, is an essential task in many computer vision and 3D data processing applications. Calculation of projection matrix using vanishing points and vanishing lines is well suited in the literature; where the intersection of parallel lines (in 3D Euclidean space) when projected on the camera image plane (by a perspective transformation) is called vanishing point and the intersection of two vanishing points (in the image plane) is called vanishing line. The aim of this paper is to propose a new formulation for easily computing the projection matrix based on three orthogonal vanishing points. It can also be used to calculate the...
Human body 3D reconstruction in multiview soccer scenes by depth optimization
, Article 24th Iranian Conference on Electrical Engineering, 10 May 2016 through 12 May 2016 ; 2016 , Pages 1591-1596 ; 9781467387897 (ISBN) ; Kasaei, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
In soccer matches, 3D reconstruction is a main part of many applications including free-viewpoint broadcasting, match analysis, augmented reality, and refereeing examination. The main challenge of 3D reconstruction in soccer scenes is the human body reconstruction. Although 3D reconstruction methods have been improved to a high extent in controlled condition, still there are lots of uncovered issues in outdoor scene reconstructions with uncontrolled conditions. In this paper, a view-dependent depth optimization method is presented which addresses two of these issues in soccer scenes. These issues include inaccurate camera calibrations and limited number of input cameras. This method will...
Evaluation and Improvement of the Existing Methods for Output Measurement of Structures Using Image Processing Applicable for Dynamic Parameter Identification Strategies
, M.Sc. Thesis Sharif University of Technology ; Rahimzadeh Rofooei, Fayaz (Supervisor) ; Mahdavi, Hossein (Co-Supervisor)
Abstract
Damage and collapse of structural systems due to externally applied loadings, are inevitable, which cause financial and human losses. Therefore, the application of structural health monitoring (SHM) strategies has attracted a lot of attention in order to estimate structural damages, optimal maintenance and preventing structural collapse. Hence, in recent decades, the development of research activities in the field of structural health monitoring and its application in civil engineering, has led to the invention of various techniques and methods in assessing the safety of structures. These methods not only should be accurate enough for confidently identifying diverse severity of damages, but...