Read the road plane from file

[Durant35]

• Ground plane dataset for KiTTI: https://drive.google.com/open?id=1yjCwlSOfAZoPNNqoMtWfEjPCfhRfJB-Z

# Plane
Width 4
Height 1
-3.335541e-03 -9.999398e-01 1.045457e-02 1.655293e+00

[Durant35]

• ./wavedata/wavedata/tools/obj_detection/obj_utils.py

def get_road_plane(img_idx, planes_dir):
    """Reads the road plane from file

    :param int img_idx : Index of image
    :param str planes_dir : directory containing plane text files

    :return plane : List containing plane equation coefficients
    """

    plane_file = planes_dir + '/%06d.txt' % img_idx

    with open(plane_file, 'r') as input_file:
        lines = input_file.readlines()
        input_file.close()

    # Plane coefficients stored in 4th row
    lines = lines[3].split()

    # Convert str to float
    lines = [float(i) for i in lines]

    plane = np.asarray(lines)

    # Ensure normal is always facing up.
    # In Kitti's frame of reference, +y is down
    if plane[1] > 0:
        plane = -plane

    # Normalize the plane coefficients
    norm = np.linalg.norm(plane[0:3])
    plane = plane / norm

    return plane

Width和Height似乎没有使用到，只用到了路面参数：(a, b, c, d)