Implement functionality for the segmentation-free paradigm

[sfikas]

Related issues

1. what happens if a detector returns 0 hits for a query ? p at X should be 0 -- we need to 'punish' this detector since it evidently failed .

• what if a detector returns a set of bboxes B, where a subset S of B contains bboxes that correspond to hits for a single query ? Solution: Only one of the bboxes in S should count as a hit.
• The reason is that if we count more than one bbox in S as a hit, (1) the effectiveness of this detector appears to be boosted (when it really isn't) (2) we open the possibility for a detector to cheat, just by submitting a S with large |S|.
• we should keep only the 'best' hit in S, in some well-defined sense.