Abstract Pattern matching is the most widely used technique for the compression of printed bi-level text images. In some printed scripts, letters normally attach to each other, or some letters have a simple relation to each other, or there may be undesired touching characters. Detecting such situations and exploiting them to reduce the library size, has a rather great effect on the compression ratio. In this paper, a lossy/lossless compression method for printed typeset bi-level text images is proposed for archiving purposes. For this, three techniques are proposed. First, the number of library prototypes is reduced by detecting and exploiting the mentioned situations. Second, a new effective encoding scheme is proposed for patterns and numbers. Third, three levels are proposed for lossy compression. Experimental results show that the proposed method works better, as high as 1.4–3.3 times in lossy case and 1.2–2.7 times in lossless case at 300 dpi, than the best existing compression methods or standards.

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