On-line freehand sketching recognition using conic section

Freehand sketching is an efficient way for conceptual design stage, and on-line sketching recognition is a precondition for human-computer interface. This paper brings usual polyline into conic section based on generalized conic section category. To avoid imaginary curves, this paper adopts least median square curvilinear regression to label stroke as a single primitive or composite primitive. For the latter, this paper put forward two-pass algorithm to process composite primitive. The experiment results show the method is effective. It is a foundation for 3D object regularization and reconstruction.