Reviewing Performance Metrics for Handwriting Recognition: Must-Rejects and Recognition Graph Scores

The performance of handwriting recognition systems is typically measured in terms of “recognition rate”. Many academic competitions work this way. However, additional external requirements may shift the view of recognition quality: Processing time and acceptable error rate may be limited, lexica may be missing, but are needed to unambiguously define result correctness. These aspects will be discussed in detail, and appropriate metrics will be proposed. A single-valued combination of these metrics may then be defined for specific application areas. It can be used in order to choose between recognition approaches or systems, and to optimize system parameters automatically.