An image processing system comprising; a controller configured to receive a digital version of a document, the controller configured to execute instructions to perform a method of extracting structured data associated with a digital version of a document which has been optical character recognized, wherein the digital version of a document is in a Tagged Image File Format (TIFF), a Joint Photographic Experts Group format, a Portable Document Format, any format that can be converted to PDF, or belongs to an image-based format, such as in a scanned file, the method comprising: a) performing a layout analysis of the digital version of the document to generate one or more layout structures associated with the document, each layout structure including a plurality of structural elements vertically or horizontally aligned where each structural element is defined as a typographical box including one or more lines of textual elements associated with the digital version of the document; b) tagging one or more of the lines of textual elements with one of a plurality of content tags, a tagged line of textual elements including structured elements of information which are associated with the plurality of content tags using one or more regular expressions or closed lists; c) generating a content-layout model (clayout model) using a sequence-based method to hierarchically segment a sequence of tagged elements associated with the generated one or more layout structures, wherein the clayout model associates the one or more content tags with respective repetitive layout positions of one of the one or more layout structures; d) tagging one or more lines of textual elements which were not tagged in step b) with one of the plurality of content tags based on inferred repetitive locations of the plurality of content tags provided by the clayout model; and e) extracting the tagged lines of textual information as representative of the structured data associated with the digital version of the document; wherein the sequence-based method comprises: c1) generating an ordered sequence of textual elements from said one or more layout structures; c2) for each tagged textual element within said ordered sequence of textual elements, generating a feature associated with the element; c3) generating a set of n-grams from the sequence of textual elements, an n-gram including an ordered sequence of n features provided by a sequence of n named elements; c4) electing sequential n-grams from the set of n-grams, the sequential n-grams defined as similar contiguous n-grams; c5) selecting the most frequent sequential n-gram from the elected sequential n-grams; and c6) generating a new sequence of the elements by matching the selected most frequent substantial n-gram against the sequence of elements associated with the document, replacing matched elements of the sequence of elements with a respective node, and associating the matched elements of the sequence of elements as children of the respective node. a) performing a layout analysis of the digital version of the document to generate one or more layout structures associated with the document, each layout structure including a plurality of structural elements vertically or horizontally aligned where each structural element is defined as a typographical box including one or more lines of textual elements associated with the digital version of the document; b) tagging one or more of the lines of textual elements with one of a plurality of content tags, a tagged line of textual elements including structured elements of information which are associated with the plurality of content tags using one or more regular expressions or closed lists; c) generating a content-layout model (clayout model) using a sequence-based method to hierarchically segment a sequence of tagged elements associated with the generated one or more layout structures, wherein the clayout model associates the one or more content tags with respective repetitive layout positions of one of the one or more layout structures; d) tagging one or more lines of textual elements which were not tagged in step b) with one of the plurality of content tags based on inferred repetitive locations of the plurality of content tags provided by the clayout model; and e) extracting the tagged lines of textual information as representative of the structured data associated with the digital version of the document; c1) generating an ordered sequence of textual elements from said one or more layout structures; c2) for each tagged textual element within said ordered sequence of textual elements, generating a feature associated with the element; c3) generating a set of n-grams from the sequence of textual elements, an n-gram including an ordered sequence of n features provided by a sequence of n named elements; c4) electing sequential n-grams from the set of n-grams, the sequential n-grams defined as similar contiguous n-grams; c5) selecting the most frequent sequential n-gram from the elected sequential n-grams; and c6) generating a new sequence of the elements by matching the selected most frequent substantial n-gram against the sequence of elements associated with the document, replacing matched elements of the sequence of elements with a respective node, and associating the matched elements of the sequence of elements as children of the respective node.