Automatic table location in documents

Table-like structures in documents are located by analysis of sub-regions (crops) thereof. The analysis involves determining the location of lines having lengths above a certain threshold and assigning these lines to groups. A set of adjacent lines is assigned to a common group if the separation between adjacent pairs of lines within the set is less than a threshold value. The crop selected as the location of the table-like structure is that having a group with the greatest number of lines. When the technique is applied to locating title-blocks in technical drawings, it is preferred to analyse crops corresponding to the corners or ends of the document. It is advantageous to analyse an image of the document at reduced resolution.