Scanning a high contrast image in bilevel mode results in image degradation. This is caused by two primary effects: blurring and thresholding. This paper expands on a method of estimating a joint distortion parameter, called the edge spread, from a star sector test chart in order to calculate the values of the point spread function width and binarization threshold. This theory is also described for variations in the source pattern which can represent degradations caused by repetition of the bilevel process as would be seen in printing then scanning, or in repeated photocopying. Estimation results are shown for the basic and extended cases.
This document was originally published by IEEE in Proceedings Sixth International Conference on Document Analysis and Recognition, 2001. Copyright restrictions may apply. DOI: 10.1109/ICDAR.2001.953968
Barney Smith, Elisa H.. (2001). "Scanner Parameter Estimation Using Bilevel Scans of Star Charts". Proceedings Sixth International Conference on Document Analysis and Recognition, 2001, 1164-1168. http://dx.doi.org/10.1109/ICDAR.2001.953968