hi, i want to download dataset form https://npm3d.fr/kitti-carla , but the speed is too slow，the download failed soon, Is there any solution to this problem?

KITTI paper:

1. Height of LIDAR: 1.73m
2. Height of Cameras: 1.65m
3. Distance between the stereo cameras is 0.54m

But in the scripts :

1. Height of LIDAR to be: 1.80m
   "The LiDAR is attached to the vehicle body with a global
   translation of (X = 0.0m, Y = 0.0m, Z = 1.80m)"

2. Height of cameras to be: 1.70m

3. Distance between the stereo cameras to be: 0.50m
   "Cameras are attached to the vehicle body with a global translation of (X = 0.30m, Y = 0.0m, Z = 1.70m)
   for camera 0 and (X = 0.30m, Y = 0.50m, Z = 1.70m) for
   camera 1"

Are these ok for a working code ? Or does usage of CARLA have something to do with this ?

Since the KITTI-CARLA is an (almost) exact simulation of the KITTI, can I reuse the calib.txt file in data_odometry_calib.zip file ?

The contents of the calib.txt file in each of the sequences is as follows:

P0: 7.188560000000e+02 0.000000000000e+00 6.071928000000e+02 0.000000000000e+00 0.000000000000e+00 7.188560000000e+02 1.852157000000e+02 0.000000000000e+00 0.000000000000e+00 0.000000000000e+00 1.000000000000e+00 0.000000000000e+00
P1: 7.188560000000e+02 0.000000000000e+00 6.071928000000e+02 -3.861448000000e+02 0.000000000000e+00 7.188560000000e+02 1.852157000000e+02 0.000000000000e+00 0.000000000000e+00 0.000000000000e+00 1.000000000000e+00 0.000000000000e+00
P2: 7.188560000000e+02 0.000000000000e+00 6.071928000000e+02 4.538225000000e+01 0.000000000000e+00 7.188560000000e+02 1.852157000000e+02 -1.130887000000e-01 0.000000000000e+00 0.000000000000e+00 1.000000000000e+00 3.779761000000e-03
P3: 7.188560000000e+02 0.000000000000e+00 6.071928000000e+02 -3.372877000000e+02 0.000000000000e+00 7.188560000000e+02 1.852157000000e+02 2.369057000000e+00 0.000000000000e+00 0.000000000000e+00 1.000000000000e+00 4.915215000000e-03
Tr: 4.276802385584e-04 -9.999672484946e-01 -8.084491683471e-03 -1.198459927713e-02 -7.210626507497e-03 8.081198471645e-03 -9.999413164504e-01 -5.403984729748e-02 9.999738645903e-01 4.859485810390e-04 -7.206933692422e-03 -2.921968648686e-01

When I run the data generation code, after one map there are always errors ERROR: Invalid session: no stream available with id, do you know how to solve it? It seems that it is because the sensors are not deleted totally.

I changed number of frames from 5000 to 50 and when loading the second map the program seg faults

Export : KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town01/generated/images_depth/0049_20.png
Export : KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town01/generated/images_depth/0049_21.png
Export : KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town01/generated/frames/frame_0049.ply
Export : KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town01/generated/poses_lidar.ply
Stop record
Destroying 50 vehicles
Destroying 32 walkers
Destroying KITTI
Elapsed time : 71.06980013847351

Map Town02
Segmentation fault (core dumped)

Anyone seen this problem before ?

It seems to work only one town at a time.

python KITTI_data_generator.py
Map Town02
Created Actor(id=135, type=vehicle.tesla.model3)
Number of spawn points : 101

..

Stop record
Destroying 50 vehicles
Destroying 33 walkers
Destroying KITTI
Elapsed time : 65.43478298187256

Map Town03
Segmentation fault (core dumped)

The self.set_attributes is a method in the sub-class. Is this a good design ? Perhaps the super class should only do a basic setup and actual setup should be sub-classes ?

class Sensor:
    initial_ts = 0.0
    initial_loc = carla.Location()
    initial_rot = carla.Rotation()

    def __init__(self, vehicle, world, actor_list, output_folder, transform):
        self.queue = queue.Queue()
        self.bp = self.set_attributes(world.get_blueprint_library())

python KITTI_data_generator.py

Map Town01
Created Actor(id=1669, type=vehicle.tesla.model3)
('Number of spawn points : ', 255)
Spawned 1 vehicles and 1 walkers
Waiting for KITTI to stop ...
KITTI stopped
('Elapsed total time : ', 35.62052607536316)
Traceback (most recent call last):
File "KITTI_data_generator.py", line 177, in
main()
File "KITTI_data_generator.py", line 86, in main
gen.screenshot(KITTI, world, actor_list, folder_output, carla.Transform(carla.Location(x=0.0, y=0, z=2.0), carla.Rotation(pitch=0, yaw=0, roll=0)))
File "/home/libing/source/simulator/kitti_carla_simulator/generator_KITTI.py", line 297, in screenshot
RGB.set_attributes(world.get_blueprint_library())
TypeError: unbound method set_attributes() must be called with RGB instance as first argument (got BlueprintLibrary instance instead)

Can anyone say what the benefit of having the LIDAR point backwards ?
lidar_transform = carla.Transform(carla.Location(x=0, y=0, z=1.80), carla.Rotation(pitch=0, yaw=180, roll=0))

Also the lidar to camera translation makes difference of lidar to camera

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]])))

Should it not be the other way around ?
@jedeschaud, Could you give some hints on this ?

Also the sensors are not synchronized:

Camera data timestamp:  3.4262565394164994
Export: KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town07/generated/image_2/000000.pngSaving lidar pointcloud at timestamp  3.525256544118747
Export: KITTI_Dataset_CARLA_v0.9.12/Carla/Maps/Town07/generated/velodyne/000000.bin

The current version of KITTI 3D dataset has the points clouds in .bin format, and I noticed that the code saves in .ply. Am I missing something?

Thanks for sharing the code!

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 ?

Hello @jedeschaud ,

How are these fixed transforms are determined ?
As I understand the (0,0,0) of a car is fixed to be the middle of the rear axle

 # Set sensors transformation from KITTI
            lidar_transform = carla.Transform(carla.Location(x=0, y=0, z=1.80), carla.Rotation(pitch=0, yaw=180, roll=0))
            cam0_transform = carla.Transform(carla.Location(x=0.30, y=0, z=1.70), carla.Rotation(pitch=0, yaw=0, roll=0))
            cam1_transform = carla.Transform(carla.Location(x=0.30, y=0.50, z=1.70), carla.Rotation(pitch=0, yaw=0, roll=0))


Atleast from the KITTI sensor setup diagram I cant seem to figure out how atleast the Location is decided from a CARLA left hand rule perspective..

Hello @jedeschaud I have found that the labels are ot present in the given synthetic dataset. I am working on synthetic to realistic point cloud data conversion. Please help on this