Possible errors in the transform_lidar_to_camera function ?

[RaviBeagle]

Hello @jedeschaud ,

The code for the function:

def transform_lidar_to_camera(lidar_transform, camera_transform):
    R_camera_vehicle = rotation_carla(camera_transform.rotation)
    R_lidar_vehicle = np.identity(3) #rotation_carla(lidar_tranform.rotation) #we want the lidar frame to have x forward
    R_lidar_camera = R_camera_vehicle.T.dot(R_lidar_vehicle)
    T_lidar_camera = R_camera_vehicle.T.dot(translation_carla(np.array([[lidar_transform.location.x],[lidar_transform.location.y],[lidar_transform.location.z]])-np.array([[camera_transform.location.x],[camera_transform.location.y],[camera_transform.location.z]])))
    return np.vstack((np.hstack((R_lidar_camera, T_lidar_camera)), [0,0,0,1]))


According to this post: https://robotics.stackexchange.com/questions/21401/how-to-make-two-frames-relative-to-each-other

R_lidar_camera = R_camera_vehicle.T.dot(R_lidar_vehicle) should be 
R_lidar_camera = R_lidar_vehicle.T.dot(R_camera_vehicle)

Also the difference in translation is: translation_carla(np.array([[lidar_transform.location.x],[lidar_transform.location.y],[lidar_transform.location.z]])-np.array([[camera_transform.location.x],[camera_transform.location.y],[camera_transform.location.z]])))

Should it not be camera - lidar ?

[RaviBeagle]

The following code gives me the correct results

def get_transform_lidar_to_camera(lidar_transform,camera_transform):
    R_camera_vehicle = rotation_carla(camera_transform.rotation)
    R_lidar_vehicle = rotation_carla(lidar_transform.rotation)
    T_camera_vehicle = np.array([[camera_transform.location.x],[-camera_transform.location.y],[camera_transform.location.z]])
    T_lidar_vehicle = np.array([[lidar_transform.location.x],[-lidar_transform.location.y],[lidar_transform.location.z]])
    Tr_camera_vehicle = np.vstack((np.hstack((R_camera_vehicle, T_camera_vehicle)), [0,0,0,1]))
    Tr_lidar_vehicle = np.vstack((np.hstack((R_lidar_vehicle, T_lidar_vehicle)), [0,0,0,1]))
    return np.linalg.inv(Tr_lidar_vehicle).dot(Tr_camera_vehicle)


[[ 1.          0.          0.          0.27000001]
 [ 0.          1.          0.          0.        ]
 [ 0.          0.          1.         -0.08000004]
 [ 0.          0.          0.          1.        ]]

which is the correct transformation when the LIDAR is not at a 180 yaw to the camera..

[zorzpapaduby]

Hello! Running this simulation is extremely slow in my case. I have noticed that if I change fps_simu to fps_simu=10 instead of 1000. Simulation runs faster, but I am not sure how it influence data generation and will it influence the final output which is supposed to be KITTI like. Do you have any suggestions on how I should approach this? Thanks