New Metrics for Evaluating Performance in Document Analysis Tasks_Application to the Table Case

Is an algorithm capable of high precision and recall at classifying lines as part of table really good at locating tables? Several document analysis tasks require gluing or cutting certain document elements to form others. The suitability of the commonly used precision and recall for such division/aggregation tasks is arguable, since their underlying assumption is that the granularity of the items at input is the same as at output. We propose new evaluation metrics especially suited for this type of tasks, and show their application in several table tasks. In the process we present robust table location and cell segmentation algorithms.