Optical character recognition systems provide a transformation of pixelized images of documents into ASCII coded text which facilitates searching, substitution, reformatting of documents etc. in a computer system. One aspect of OCR functionality is to convert handwritten and typewriter typed documents, books, medical journals, etc. into for example Internet or Intranet searchable documents. Generally, the quality of information retrieval and document searching is considerably enhanced if all documents are electronically retrievable and searchable. For example, a company Intranet system can link together all old and new documents of an enterprise through extensive use of OCR functionality implemented as a part of the Intranet (or as part of the Internet if the documents are of public interest).
However, the quality of the OCR functionality is limited due to the fact that the complexity of an OCR system in itself is a challenge. It is difficult to provide an OCR functionality that can solve any problem encountered when trying to convert images of text into computer coded text. One such problem is due to imprint of at least two characters on top of each other, or with an offset between them, which may be encountered in typewriter printed documents. The printing arms or printing wheels or similar typewriter mechanisms may have some mechanical faults that provides a misalignment when the arms or the printing wheel, the paper etc. is shifted to a new position, which may result in a movement along the text line that is too small compared to the actual width of the character, resulting in a misaligned printing of the characters on a text line.
The effect of such double printed images is that the OCR system is unable to recognize the respective character images in the double printed images, and convert them to correct ASCII characters, for example. Usually, OCR systems provide output data comprising a list of uncertainly recognized characters with a measuring of the degree of uncertainty or certainty that respective characters have been recognized. This value is sometimes referred to as a score value, as known to a person skilled in the art. Such double printed character images will therefore be identifiable as such, and their position on a text page, in words etc., can be identified. However, the respective unrecognizable double printed character images must be distinguished from unrecognizable single character images.