def _filter_boxes(boxes, min_size):
        """ Remove all boxes with any side smaller than min_size """
        ws = boxes[:, 2] - boxes[:, 0] + 1
        hs = boxes[:, 3] - boxes[:, 1] + 1
        keep = np.where((ws >= min_size) & (hs >= min_size))[0]
        return keep
 Remove all boxes with any side smaller than min_size 
faster_rcnn/operator_py/proposal.py