Form Document Representation and Identiication ?

A form processing system aims to extract meaningful data from a form document for ooce automation 1, 2, 3]. The main interest is to extract user lled-in data which is considered to be meaningful. However, in order to perform such a task, the structure of the form should be known in advance. The form structure can be obtained by processing a blank model form on which no user lled-in data exists. The model form may be stored in a database and when an instance form is presented to the system, its type can be identiied by matching with one of the model forms in the database. Meaningful data can then be automatically extracted. A form document can be easily represented by its image. But, such a physical information may not be appropriate, since the form or its image risks to be modiied geometrically or to be distorted due to printing or digitization. On the other hand, logical structure represents the semantics of the form and same logical structure can be formatted in a variety of physical layouts. The geometrical structure should be mapped to a logical structure by considering the logical relations. In this paper, our aim is to develop a logical representation for form documents and to use the representation for identiication. We propose a heuristic algorithm in order to transform geometric structure of a form into a logical structure by using horizontal and vertical lines which exist on the form. The logical structure is represented by a hierarchical tree. The hierarchy of the tree corresponds to the hierarchy of the blocks in the form document. The proposed representation is close to human point of view for the form structure. Logically same forms have the same hierarchical tree structure. Also, geometrical modiications and slight variations on a form are handled by the proposed representation. A hierarchical structure is proposed to represent the logical layout of a form by using horizontal and vertical lines. The main aim is to partition the form into blocks which can further be divided until cells (the smallest blocks) are reached. The partitioning results in a tree where the root is the form itself and the leaf nodes correspond to the cells. The heuristic behind the approach is that the blocks which contain similar information are grouped together and these group of blocks are separated by the lines relatively longer than the others. Such lines …