A Free-Sketch Recognition Method for Chemical Structural Formula.

Chemical Structural Formula(CSF) recognition plays an important role in the molecular design and component retrieval. However, sketch-based CSF recognition remains an obstacle in current retrieval systems. This paper introduces a system for sketch CSF recognition on smart mobile devices. A dual-mode-based method is proposed to distinguish the gestures for character inputs and noncharacter inputs instead of the ordinary segmentation approaches. An attribute graph model is established to describe effectively all necessary information of a sketched CSF. Chemical knowledge is adopted to refine the candidates of structure relationship among elements. The experiments results demonstrate that the proposed method outperforms the existing methods for free-sketch CSFs on effectiveness and flexibility.