def generate_anchors(base_size=16, ratios=(0.5, 1, 2), scales=(8, 16, 32)):
    """
    Generate anchor (reference) windows by enumerating aspect ratios X
    scales wrt a reference (0, 0, 15, 15) window.
    """

    base_anchor = np.array([1, 1, base_size, base_size]) - 1
    ratio_anchors = _ratio_enum(base_anchor, ratios)
    anchors = np.vstack(
        [
            _scale_enum(ratio_anchors[i, :], scales)
            for i in range(ratio_anchors.shape[0])
        ]
    )
    return anchors
Generate anchor (reference) windows by enumerating aspect ratios X
scales wrt a reference (0, 0, 15, 15) window.
tests/unittest/ops/test_proposal.py