Tracing and representation of human line drawings

An approach to the representation of arbitrary line drawings is presented. With this approach the system makes a tracing of line drawings similar to the way a human normally does, and incorporates the result of the tracing sequence into the structural representation of the line drawing. Following the sequence of line drawings identified by the tracing, the critical point segmentation method is proposed to extract all the local feature points for representation. To make the representation size and rotation invariant, the authors introduce the critical point normalization method based on orthonormal transformation. Experimental results are shown