DaStereoWithConics

Chair for Computer Aided Medical Procedures & Augmented Reality
Lehrstuhl für Informatikanwendungen in der Medizin & Augmented Reality

Master thesis: Stereo Vision with Conical and Circular Features

Thesis by: Veselin Dikov Advisor: Nassir Navab Supervision by: Nassir Navab Due date: finished

Abstract

The topic of this master thesis is stereo vision with conical (elliptical) and circular features. Stereo vision is a major subject in the scientific field of computer vision. The main task in stereo vision is the 3D reconstruction of a scene given images of the scene taken by two cameras. But first, the geometrical relations between both cameras, represented by the so called epipolar geometry, need to be found. The traditional algorithms that estimate the epipolar geometry between two images are based on point image features.

Ellipses and circles as image features have certain advantages compared to point features: they can be extracted more easily and with higher accuracy from the image, even when they are partially occluded, and they can be identified more easily in multiple images. Such features can be found in many man-made objects, even if point features are completely missing. It is theoretically proven that four conical features in general position are enough for estimation of the epipolar geometry, but, unfortunately, not in a linear manner.

Innovative ideas for handling linearly this estimation problem for certain specific cases are developed in this thesis. We propose an algorithm, which finds groups of ellipses that lie on one and the same plane in space. Based on the results of this algorithm, we develop linear methods for estimating the epipolar geometry. We show that the minimal configuration of three ellipses suffices, given that two of the ellipses lie on one plane. Furthermore, we show that the epipolar geometry can be computed from two circles on one plane. For this we deploy selfcalibration methods, which were not used in combination with binocular stereo vision so far. In the case when the cameras are known ( i.e. their parameters like focal length and relative position) we show that two coplanar ellipses or two circles in general position are also sufficient.

Resources

Literature


Students.ProjectForm
Title: Stereo Vision with Conical and Circular Features
Abstract: The topic of this master thesis is stereo vision with conical (elliptical) and circular features. Stereo vision is a major subject in the scientific field of computer vision. The main task in stereo vision is the 3D reconstruction of a scene given images of the scene taken by two cameras. But first, the geometrical relations between both cameras, represented by the so called epipolar geometry, need to be found. The traditional algorithms that estimate the epipolar geometry between two images are based on point image features. Ellipses and circles as image features have certain advantages compared to point features: they can be extracted more easily and with higher accuracy from the image, even when they are partially occluded, and they can be identified more easily in multiple images. Such features can be found in many man-made objects, even if point features are completely missing. It is theoretically proven that four conical features in general position are enough for estimation of the epipolar geometry, but, unfortunately, not in a linear manner. Innovative ideas for handling linearly this estimation problem for certain specific cases are developed in this thesis. We propose an algorithm, which finds groups of ellipses that lie on one and the same plane in space. Based on the results of this algorithm, we develop linear methods for estimating the epipolar geometry. We show that the minimal configuration of three ellipses suffices, given that two of the ellipses lie on one plane. Furthermore, we show that the epipolar geometry can be computed from two circles on one plane. For this we deploy selfcalibration methods, which were not used in combination with binocular stereo vision so far. In the case when the cameras are known ( i.e. their parameters like focal length and relative position) we show that two coplanar ellipses or two circles in general position are also sufficient.
Student: Veselin Dikov
Director: Nassir Navab
Supervisor: Nassir Navab, Stefan Rahmann
Type: DA/MA/BA
Area:  
Status: finished
Start:  
Finish:  
Thesis (optional):  
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