On the Recovery of Oriented Documents from Single ImagesPaul Clark, Majid Mirmehdi, On the Recovery of Oriented Documents from Single Images. CSTR-01-004, Department of Computer Science, University of Bristol. November 2001. PDF, 822 Kbytes.
A method is presented for the fronto-parallel recovery of text documents in imag es of real scenes. Initially an extension of the standard 2D projection profile, commonly used in d ocument recognition, is introduced to locate the horizontal vanishing point of t he text plane. This allows us to segment the lines of text, which are then analysed to reveal t he style of justification of the paragraphs. The change in line spacings exhibited due to perspective is then used to recover the vertical vanishing point of the document. We do not assume any knowledge o f the focal length of the camera. Finally, a fronto-parallel view is recovered, suitable for OCR or other high-lev el recognition. We provide results demonstrating the algorithm's performance on documents over a wide range of orientations.