Document style census for OCR

Four methods of converting paper documents to computer-readable form are compared with regard to hypothetical labor cost: keyboarding, omnifont OCR, style-specific OCR, and style-constrained or style-adaptive OCR. The best choice is determined primarily by (1) the reject rates of the various OCR systems at a given error rate, (2) the fraction of the material that must be labeled for training the system, and (3) the cost of partitioning the material according to style. For large corpora, sampling strategies are proposed both for estimating conversion costs and for taking advantage of style homogeneity.