A Knowledge-Aided Line Network Oriented Vectorisation Method for Engineering Drawings

Abstract:

Vectorisation is the foundation in recognising engineering components from paper form drawings. Due to the complexity of problems and the difficulty of techniques, the vectorisation method relying merely on the image itself cannot get satisfactory results. It is now widely agreed that the knowledge must be applied more or less to aid the vectorisation. The capability of the vectorisation method itself should also be thus improved. This paper analyses the problems of existing vectorisation methods, introduces the complete concept of global vectorisation, and proposes a whole new line network oriented global vectorisation method. This method uses global information to vectorise a line in one step, and carries out the global vectorisation of line networks. Therefore, the problem of separating one line is solved, and a complex analysis of crossings is avoided. The performance of vectorisation is improved clearly. Furthermore, it can vectorise lines in any orientations well, and can vectorise a dashed line in one step. Aided by the related knowledge, local details of vectorisation are refined. A performance evaluation compared with other vectorisation methods is also included.