The Impact Centre of Competence dataset contains more than half a million representative text-based images compiled by a number of major European libraries. Covering texts from as early as 1500, and containing material from newspapers, books, pamphlets and typewritten notes, the dataset is an invaluable resource for future research into imaging technology, OCR and language enrichment. A carefully selected subset of these images has been reproduced with accompanying “ground truth”. In digital imaging and OCR, ground truth is the objective verification of the particular properties of a digital image, used to test the accuracy of automated image analysis processes. The…