Object Height Estimation

Abstract

This thesis describes methods that mainly deals with the real world height measurement of objects from various images of scenes. The concept of Projective Geometry is used extensively. It forms the basis for accurate estimation algorithms. The thesis is mainly focused on techniques that deals with uncalibrated images; that is the intrinsic properties (focal length and aspect ratio) of the camera or its pose (orientation and position) are not known. There is no need of special calibration device as the geometric characteristics of the scene is extensively used. Initially the height is estimated by using the pinhole projection formula. But it requires the use of camera intrinsic properties. So we move on to metrology techniques. The geometry of single views is explored and height of the objects in the scene is estimated from the image. To achieve this the properties of planar homographies and planar homologies are extensively exploited. Then properties of vanishing points and lines are also exploited to calculate distances from planes. This also helps in determining the height of the objects in the scene. The general techniques used in this thesis can be applied to several areas. Examples are presented of commercial, industrial and artistic use.