Pre-marking methods for 3D object recognition

Two premarking methods are proposed for a new 3D object recognition system under development at the University of Toronto. In this system, an object is modeled using only a small number of 2D distinct perspective views (standard views) predefined wit the help of markers placed on the object. During the recognition process, a standard view is acquired by first determining its surface normal (standard-view axis), and then aligning the camera´s optical axis with it. Standard-view axes are obtained by analyzing the images of the markers. A morphological skeleton transform (MST) is used for the extraction of required marker features. This work presents the analytical solution for the two proposed premarking schemes, based on circular markers, that can be used in acquiring standard views of objects. Specific issues addressed include: the determination of the perspective distortion and its relative importance, the determination of the transformation parameters required for camera alignment, and the use of a class of MST, pseudo-Euclidean skeletons, for feature extraction