Multiple View Geometry Ilan Shimshoni Dept of Management Information Systems University of Haifa ishimshoni@mis.haifa.ac.il
Examples of Applications Visual robot navigation 3D reconstruction from video Was there a goal in a game from two video cameras?
What do we know? Camera parameters Camera position with respect to the scene Relative camera position (known or constrained) Objects in the scene Their positions Characteristics of objects in the scene Nothing!!!
The more we know the easier it is. The more we need to know the harder it is to perform the experiment. Example stereo reconstruction Camera parameters known Relative camera positions known and constrained Goal: reconstruct scene. Find for each point in the first image its corresponding point in the second image. How can we make the task easier?
Another example: scene reconstruction from a video sequence Camera parameters not known Camera positions not known Much easier for the user Something in between: Scene reconstruction from a set of images taken by a plane (geodesic dept) Position of plane known quite accurately High quality camera which has been accurately calibrated
How do we solve problems? Example: Pose estimation The algorithm is given: A model of a 3D object The geometric imaging parameters of the camera An image of the object Goal: Calculate accurately the position of the camera with respect to the object
Applications A robot would like to grab an object with its gripper using a camera which is positioned on the robot A robot would like to know where it is. The object is the room. A satellite would like to know its orientation in space from an image it took of the stars. The object is the universe
The input:
Steps in developing an algorithm Define f(X,x,) Find a method to compute such that f(X,x,) = 0 What should we do if there is measurement noise in x? How do we match x to X? How do we deal with incorrect matches (outliers)? Build a full system.
Criminisi
MIT city scanning project Produce image hemispheres Localize hemispheres using GPS Match hemispheres using vision methods Find accurate positions of cameras Reconstruct buildings Reconstruct fine details
3D reconstruction from image sequence
Cipolla 2008
Elections November 2008