Example Scene
=============

This page contains a complete example scene in JSON format that can be used
as a template or for testing.

Complete Scene JSON
-------------------

The following JSON represents a simple scene with:

- An ego vehicle with a 3-frame trajectory
- One camera sensor
- One LiDAR sensor  
- One radar sensor
- One dynamic vehicle actor

.. literalinclude:: _static/example_scene.json
   :language: json
   :caption: example_scene.json


Loading the Example
-------------------

To load and work with this example:

.. code-block:: python

    from mimic_data_api import Scene

    # Copy the JSON above to a file named "example_scene.json"
    # Then load it:
    
    with open("example_scene.json", "r") as f:
        scene = Scene.model_validate_json(f.read())

    # Inspect the loaded scene
    print(f"Ego trajectory frames: {len(scene.ego_vehicle.trajectory.timestamps)}")
    print(f"Cameras: {len(scene.ego_vehicle.sensors.cameras)}")
    print(f"LiDARs: {len(scene.ego_vehicle.sensors.lidars or [])}")
    print(f"Radars: {len(scene.ego_vehicle.sensors.radars or [])}")
    print(f"Actors: {len(scene.actors)}")


Scene Visualization
-------------------

The scene described above represents:

.. code-block:: text

    Time: t=0s                    Time: t=2s
    
         y (left)                      y (left)
         ^                             ^
         |                             |
    -----+------> x (forward)     -----+------> x (forward)
         |                             |
         
    [Actor]                       [Actor]
    x=30m, y=3.5m                 x=46m, y=3.5m
    (adjacent lane)               (adjacent lane)
    
    [Ego]                         [Ego]
    x=0m, y=0m                    x=20m, y=0m
    (origin)                      (moved forward)

The ego vehicle travels forward at 10 m/s, while the actor vehicle (in the adjacent lane at y=3.5m) travels at 8 m/s.


Minimal Scene Example
---------------------

A minimal valid scene with just a camera:

.. code-block:: json

    {
      "ego_vehicle": {
        "trajectory": {
          "timestamps": [0.0],
          "object2world": [
            [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]
          ],
          "angular_velocity": null,
          "linear_velocity": null
        },
        "sensors": {
          "cameras": [
            {
              "id": 1,
              "name": "camera",
              "camera_model": "pinhole",
              "distortion_parameters": {
                "p1": 0, "p2": 0, "k1": 0, "k2": 0, "k3": 0, "k4": 0
              },
              "extrinsics": [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]],
              "trajectory": {
                "timestamps": [0.0],
                "object2world": [
                  [[1, 0, 0, 0], [0, 1, 0, 0], [0, 0, 1, 0], [0, 0, 0, 1]]
                ],
                "angular_velocity": null,
                "linear_velocity": null
              },
              "intrinsics": {
                "fx": 500, "fy": 500, "cx": 320, "cy": 240,
                "skew": 0, "height": 480, "width": 640
              },
              "images_data": [
                {
                  "filepath": "image.png",
                  "timestamp": 0.0,
                  "undistorded": true,
                  "rolling_shutter": {
                    "readout_time": 0.0,
                    "readout_direction": "global"
                  }
                }
              ]
            }
          ],
          "lidars": null,
          "radars": null
        }
      },
      "actors": []
    }

This minimal example contains the bare minimum required fields for a valid scene.


Download
--------

:download:`Download example_scene.json <_static/example_scene.json>`