PointCloud class support conert to open3d

[HowcanoeWang]

in some cases, need to use open3d for further processing

[HowcanoeWang]

def to_open3d(idp_pcd):
    final_pcd = o3d.geometry.PointCloud()
    final_pcd.points = o3d.utility.Vector3dVector(idp_pcd._points)
    color_np = idp_pcd.colors/255
    # color_np = np.insert(color_np, 2, 0.5, axis=1)
    # print(color_np)
    final_pcd.colors = o3d.utility.Vector3dVector(color_np)
    return final_pcd