1. A method for enabling a data capture system to capture data from a document image corresponding to a document, the method comprising: defining a flexible structure description for the document, the flexible structure description comprising descriptions of structures in the document and detection information to facilitate detection of said structures in the document image, wherein the detection information specifies whether a structure is to be detected with reference to its placement within a page of the document, or with reference to its placement within the document as a whole; and provisioning a data capture system with the flexible structure description.