204 lines
8.8 KiB
Markdown
204 lines
8.8 KiB
Markdown
<h1>Measurements</h1>
|
|
|
|
!!! important
|
|
Since version 0.8.0 the measurements received by the client are in SI
|
|
units. All locations have been converted to `meters` and speeds to
|
|
`meters/second`.
|
|
|
|
Every frame the server sends a package with the measurements and images gathered
|
|
to the client. This document describes the details of these measurements.
|
|
|
|
Time-stamps
|
|
-----------
|
|
|
|
Every frame is described by three different counters/time-stamps
|
|
|
|
Key | Type | Units | Description
|
|
-------------------------- | --------- | ------------ | ------------
|
|
frame | uint64 | | Frame number (it is **not** restarted on each episode).
|
|
platform_timestamp | uint32 | milliseconds | Time-stamp of the current frame, as given by the OS.
|
|
game_timestamp | uint32 | milliseconds | In-game time-stamp, elapsed since the beginning of the current episode.
|
|
|
|
In real-time mode, the elapsed time between two time steps should be similar
|
|
both platform and game time-stamps. When run in fixed-time step, the game
|
|
time-stamp increments in constant time steps (delta=1/FPS) while the platform
|
|
time-stamp keeps the actual time elapsed.
|
|
|
|
Player measurements
|
|
-------------------
|
|
|
|
Key | Type | Units | Description
|
|
-------------------------- | ----------- | ------ | ------------
|
|
transform | Transform | | World transform of the player (contains a locations and a rotation) respect the vehicle's mesh pivot.
|
|
bounding_box | BoundingBox | | Bounding box of the player.
|
|
acceleration | Vector3D | m/s^2 | Current acceleration of the player.
|
|
forward_speed | float | m/s | Forward speed of the player.
|
|
collision_vehicles | float | kg*m/s | Collision intensity with other vehicles.
|
|
collision_pedestrians | float | kg*m/s | Collision intensity with pedestrians.
|
|
collision_other | float | kg*m/s | General collision intensity (everything else but pedestrians and vehicles).
|
|
intersection_otherlane | float | | Percentage of the vehicle invading other lanes.
|
|
intersection_offroad | float | | Percentage of the vehicle off-road.
|
|
autopilot_control | Control | | Vehicle's autopilot control that would apply this frame.
|
|
|
|
<h4>Transform</h4>
|
|
|
|
The transform contains the location and rotation of the player.
|
|
|
|
Key | Type | Units | Description
|
|
-------------------------- | ---------- | ------- | ------------
|
|
location | Vector3D | m | World location.
|
|
orientation *[deprecated]* | Vector3D | | Orientation in Cartesian coordinates.
|
|
rotation | Rotation3D | degrees | Pitch, roll, and yaw.
|
|
|
|
<h4>BoundingBox</h4>
|
|
|
|
Contains the transform and extent of a bounding box.
|
|
|
|
Key | Type | Units | Description
|
|
-------------------------- | ---------- | ------- | ------------
|
|
transform | Transform | | Transform of the bounding box relative to the vehicle.
|
|
extent | Vector3D | m | Radii dimensions of the bounding box (half-box).
|
|
|
|
<h4>Collision</h4>
|
|
|
|
Collision variables keep an accumulation of all the collisions occurred during
|
|
this episode. Every collision contributes proportionally to the intensity of the
|
|
collision (norm of the normal impulse between the two colliding objects).
|
|
|
|
Three different counts are kept (pedestrians, vehicles, and other). Colliding
|
|
objects are classified based on their tag (same as for semantic segmentation).
|
|
|
|
!!! Bug
|
|
See [#13 Collisions are not annotated when vehicle's speed is low](https://github.com/carla-simulator/carla/issues/13)
|
|
|
|
Collisions are not annotated if the vehicle is not moving (<1km/h) to avoid
|
|
annotating undesired collision due to mistakes in the AI of non-player agents.
|
|
|
|
<h4>Lane/off-road intersection</h4>
|
|
|
|
The lane intersection measures the percentage of the vehicle invading the
|
|
opposite lane. The off-road intersection measures the percentage of the vehicle
|
|
outside the road.
|
|
|
|
These values are computed intersecting the bounding box of the vehicle (as a 2D
|
|
rectangle) against the map image of the city. These images are generated in the
|
|
editor and serialized for runtime use. You can find them too in the release
|
|
package under the folder "RoadMaps".
|
|
|
|
<h4>Autopilot control</h4>
|
|
|
|
The `autopilot_control` measurement contains the control values that the in-game
|
|
autopilot system would apply as if it were controlling the vehicle.
|
|
|
|
This is the same structure used to send the vehicle control to the server.
|
|
|
|
Key | Type | Description
|
|
-------------------------- | --------- | ------------
|
|
steer | float | Steering angle between [-1.0, 1.0] (*)
|
|
throttle | float | Throttle input between [ 0.0, 1.0]
|
|
brake | float | Brake input between [ 0.0, 1.0]
|
|
hand_brake | bool | Whether the hand-brake is engaged
|
|
reverse | bool | Whether the vehicle is in reverse gear
|
|
|
|
To activate the autopilot from the client, send this `autopilot_control` back
|
|
to the server. Note that you can modify it before sending it back.
|
|
|
|
```py
|
|
measurements, sensor_data = carla_client.read_data()
|
|
control = measurements.player_measurements.autopilot_control
|
|
# modify here control if wanted.
|
|
carla_client.send_control(control)
|
|
```
|
|
|
|
(*) The actual steering angle depends on the vehicle used. The default Mustang
|
|
has a maximum steering angle of 70 degrees (this can be checked in the vehicle's
|
|
front wheel blueprint).
|
|
|
|
|
|
|
|
Non-player agents info
|
|
----------------------
|
|
|
|
!!! important
|
|
Since version 0.8.0 the player vehicle is not sent in the list of non-player
|
|
agents.
|
|
|
|
To receive info of every non-player agent in the scene every frame you need to
|
|
activate this option in the settings file sent by the client at the beginning of
|
|
the episode.
|
|
|
|
```ini
|
|
[CARLA/Server]
|
|
SendNonPlayerAgentsInfo=true
|
|
```
|
|
|
|
If enabled, the server attaches a list of agents to the measurements package
|
|
every frame. Each of these agents has an unique id that identifies it, and
|
|
belongs to one of the following classes
|
|
|
|
* Vehicle
|
|
* Pedestrian
|
|
* Traffic ligth
|
|
* Speed limit sign
|
|
|
|
Each of them can be accessed in Python by checking if the agent object has the
|
|
field enabled
|
|
|
|
```python
|
|
measurements, sensor_data = client.read_data()
|
|
|
|
for agent in measurements.non_player_agents:
|
|
agent.id # unique id of the agent
|
|
if agent.HasField('vehicle'):
|
|
agent.vehicle.forward_speed
|
|
agent.vehicle.transform
|
|
agent.vehicle.bounding_box
|
|
```
|
|
|
|
<h6>Vehicle</h6>
|
|
|
|
Key | Type | Description
|
|
------------------------------- | --------- | ------------
|
|
id | uint32 | Agent ID
|
|
vehicle.forward_speed | float | Forward speed of the vehicle in m/s, is the linear speed projected to the forward vector of the chassis of the vehicle
|
|
vehicle.transform | Transform | Agent-to-world transform
|
|
vehicle.bounding_box.transform | Transform | Transform of the bounding box relative to the vehicle
|
|
vehicle.bounding_box.extent | Vector3D | Radii dimensions of the bounding box in meters
|
|
|
|
<h6>Pedestrian</h6>
|
|
|
|
Key | Type | Description
|
|
--------------------------------- | --------- | ------------
|
|
id | uint32 | Agent ID
|
|
pedestrian.forward_speed | float | Forward speed of the pedestrian in m/s
|
|
pedestrian.transform | Transform | Agent-to-world transform
|
|
pedestrian.bounding_box.transform | Transform | Transform of the bounding box relative to the pedestrian
|
|
pedestrian.bounding_box.extent | Vector3D | Radii dimensions of the bounding box in meters (*)
|
|
|
|
<small>(*) At this point every pedestrian is assumed to have the same
|
|
bounding-box size.</small>
|
|
|
|
<h6>Traffic light</h6>
|
|
|
|
Key | Type | Description
|
|
---------------------------- | --------- | ------------
|
|
id | uint32 | Agent ID
|
|
traffic_light.transform | Transform | Agent-to-world transform
|
|
traffic_light.state | enum | Traffic light state; `GREEN`, `YELLOW`, or `RED`
|
|
|
|
<h6>Speed limit sign</h6>
|
|
|
|
Key | Type | Description
|
|
---------------------------- | --------- | ------------
|
|
id | uint32 | Agent ID
|
|
speed_limit_sign.transform | Transform | Agent-to-world transform
|
|
speed_limit_sign.speed_limit | float | Speed limit in m/s
|
|
|
|
<h4>Transform and bounding box</h4>
|
|
|
|
The transform defines the location and orientation of the agent. The transform
|
|
of the bounding box is given relative to the vehicle. The box extent gives the
|
|
radii dimensions of the bounding box of the agent.
|
|
|
|
|