טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentLivshitz Dmitry
SubjectRobotic Self Location Using Three Dimensional Fiducials
and Omnidirectional Cameras
DepartmentDepartment of Computer Science
Supervisor Professor Alfred Bruckstein


Abstract

This project presents a robot navigation system designated for testing a novel approach to self-location. The system consists of a mobile robot with a parabolic camera mounted on and a PC Workstation carrying out the computations. The parabolic camera provides the navigation system with full 360° field of view images which serve as a feedback for a robot trajectory correction. A robot self-location procedure uses a number of specially designed locating objects called fiducials to determine the robot position. The proposed fiducials are covered with a three dimensional pattern which makes possible the pose-estimation without complex 3D reconstruction methods as the currently available approaches require. The main idea is that if an observer looks at such a fiducial from some unknown angle he can easily figure out what this angle is. The only thing to do is to calculate the average amount of light from the fiducial reaching the observer. In terms of image processing this implies calculating an average grayscale value over the fiducial in a picture taken by the observer. Having at least two fiducials at his disposal the observer, therefore, knows the angles at which he sees them and can estimate his position. In addition, a single panoramic image obtained from the camera contains a complete scene of the robot environment along with all of the fiducials. This feature of panoramic images introduces further simplification into the self-location algorithm. Some experiments were conducted and the corresponding estimation results are presented. A shape of a mirror which maximizes the fiducials’ resolution on the image plane was calculated. Such a mirror is optimal for the presented pose estimation algorithm and can be used to enlarge the robot working area.