Patent ID: 7519221

Claim:
A method for creating an electronic version of a document, comprising: using a computer to perform: receiving images for the document; extracting character images from the images; generating a synthetic font for the document from the extracted character images, wherein generating the synthetic font involves: producing glyphs from the extracted character images, wherein producing glyphs from the extracted character images involves grouping similar character images into clusters, and iteratively: registering extracted character images in each cluster with sub-pixel accuracy, extracting a high-resolution, noise-reduced prototype from the registered character images for each cluster, measuring a distance from each registered character image to its associated prototype, and using the measured distances to purify each cluster via histogram analysis of inter-cluster and intra-cluster distances; obtaining character labels for the glyphs; and using the glyphs and associated character labels to form the synthetic font; and constructing the electronic version of the document by, using the synthetic font to represent text regions of the document, wherein the synthetic font represents both a logical content and a visual appearance of characters in the text regions, wherein the visual appearance of characters in the synthetic font are faithful replicas of corresponding characters on printed pages from which the images were generated, and using image-segments extracted from the images for the document to represent non-text regions of the document.