Automatic performance evaluation for video text detection

We propose an objective, comprehensive and difficulty-independent performance evaluation protocol for video text detection algorithms. The protocol includes a positive set and a negative set of indices at textbox level, which evaluate the detection quality in terms of both location accuracy and fragmentation of the detected textboxes. In the protocol, we assign a detection difficulty (DD) level to each ground truth textbox. The performance indices can then be normalized with respect to the textbox DD level and are therefore independent of the ground truth difficulty. We also assign a detection importance (DI) level to each ground truth textbox. The overall detection rate is the DI-weighted average of the detection qualities of all ground truth textboxes, which makes the detection rate more accurate to reveal the real performance. The automatic performance evaluation scheme has been applied on a text detection approach to determine the best parameters that can yield the best detection results.