Suppress overlapping detections.
Original code from [1]_ has been adapted to include confidence score.
.. [1] http://www.pyimagesearch.com/2015/02/16/
faster-non-maximum-suppression-python/
Examples
--------
>>> boxes = [d.roi for d in detections]
>>> scores = [d.confidence for d in detections]
>>> indices = non_max_suppression(boxes, max_bbox_overlap, scores)
>>> detections = [detections[i] for i in indices]
Parameters
----------
boxes : ndarray
Array of ROIs (x, y, width, height).
max_bbox_overlap : float
ROIs that overlap more than this values are suppressed.
scores : Optional[array_like]
Detector confidence score.
Returns
-------
List[int]
Returns indices of detections that have survived non-maxima suppression.