Additional literature for QA Spec

[kba]

More references you might want to include:

• Leifert & Labahn 2019: End-to-End Measure for Text Recognition (on CER and derived metrics, analysis of reading order, segmentation and geometry influences)
• Zhang et al 2021: Rethinking Semantic Segmentation Evaluation for Explainability and Model Selection (semantic segmentation metrics like IoU discussed specifically with regard to over-segmentation and under-segmentation, proposes new metrics too)
• Rice 1996: Measuring the Accuracy of Page-Reading Systems (on distance algorithms, rates, derived metrics)
• Kanai & Rice 1995: Automated Evaluation of OCR Zoning (on layout evaluation, with metrics like Move Counting)
• Alberti et al 2017: Open Evaluation Tool for Layout Analysis of Document Images (basic metrics around layout evaluation)
• Clausner et al 2011: Scenario Driven In-Depth Performance Evaluation of Document Layout Analysis Methods (original PRImA Layout Performance Score and discussion)

Originally posted by @bertsky in https://github.com/OCR-D/spec/pull/225#pullrequestreview-1301262274