This paper describes our efforts in building a heritage corpus of Alpine texts. We have already digitized the yearbooks of the Swiss Alpine Club from 1864 until 1982.
This corpus poses special challenges since the yearbooks are multilingual and vary in orthography and layout. We discuss methods to improve OCR performance and experiment with combining two different OCR programs with the goal to reduce the number of OCR errors. We describe a merging procedure that uses a unigram language model trained on the uncorrected corpus itself to select the best alternative, and report on evaluation results which show that the merging procedure helps to improve OCR quality.