Evaluating line drawings of human face

This paper presents the results of a study in which type of line drawings intended to convey 3D faces by using the normal estimation method based on the face domain knowledge, including facial expressions, facial orientation and the regions of five senses. Estimated lines include occluding contours, suggestive contours, ridges and valleys, apparent ridges, and lines from shaded images. Our findings suggest that different style of line drawing has its own advantage in depicting different parts of human face, and that errors in depiction are localized in particular regions of human face. Our study also shows the result that which kind of lines can do better in depicting special parts of human face for different expressions, like eyes, nose, mouth and so on. Finally, we generate optimized line drawing results for different face models to illustrate the efficiency of our evaluation result.