Structural rectification of non-planar document images: Application to graphics recognition

Abstract

Document analysis and graphics recognition algorithms are normally applied to the processing of images of 2D documents scanned when flattened against a planar surface. Technological advancements in recent years have led to a situation in which digital cameras with high resolution are widely available. Consequently, traditional graphics recognition tasks may be updated to accommodate document images captured through a camera in an uncontrolled environment. In this paper the problem of document image rectification is discussed. The rectification targets the correction of perspective and geometric distortions of document images taken from uncalibrated cameras, by synthesizing new views which are better suited for existing graphics recognition and document analysis techniques. The proposed approach targets cases in which the document is not necessarily flat, without relaying on specific modeling assumptions, and by utilizing one or more overlapping views of the document. Document image rectification results are provided for several cases.