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