Ground truth for Neue Zürcher Zeitung black letter period

The Neue Zürcher Zeitung (NZZ) has been publishing in black letter from its very first issue in 1780 until 1947. From this time period, we randomly sampled one frontpage per year, resulting in a total of 167 pages. We chose frontpages because they typically contain highly relevant material and because we want to make sure not to sample pages containing exclusively advertisements or stock information. During certain periods, the NZZ was published several times a day, and there were supplements, too. Due to incomplete metadata, the sampling included frontpages from supplements.<br>We manually corrected the text on all pages, which now serve as input data for training new OCR systems and to improve their performance.

《新苏黎世报》（Neue Zürcher Zeitung，简称NZZ）自1780年创刊首刊至1947年，始终采用黑字体（black letter）排版。在此时间区间内，我们按年随机抽取一份头版，最终累计获得167页样本。我们选择头版作为样本，一是因其通常刊载相关性极强的核心内容，二是为避免仅抽取包含广告或股票信息的版面。在部分时期，《新苏黎世报》每日发行多版次，同时附带副刊。受限于元数据不全，本次抽样亦纳入了副刊的头版内容。
我们对所有样本页面的文本开展了人工校正工作，这些校正后的页面现已作为训练新型光学字符识别（Optical Character Recognition，OCR）系统的输入数据，用于优化该类系统的识别性能。