Occupancy Grid

This section describes the Occupancy Grid, which represents the space of detected objects by dividing it into cell-sized units of fixed dimensions.

Occupancy Grid

Create Occupancy Grid

1. Go to Tools > Occupancy Grid.

2. Set the Cell Size and Number of cells per row/column, then click Create.

The terms "Interval" and "Size" in the Occupancy Grid window have been updated as shown below.

• Interval → Cell Size

• Size → Number of cells per row/column

• Grid Settings (m)

  • Cell Size : Size of one Occupancy Grid cell

    • Range value: 0.1 ~ 1

    • Default value: 0.5

  • Number of cells per row/column : A total number of Grids from the Ego Vehicle to the distance of the Occupancy Grid boundary

    • Range value: 10 ~ 20

    • Default value: 10

      Example: When set to 10 cells per row and column, the number of grids doubles to 20.

3. When an object around the Ego-vehicle is detected, its position is recognized in the cube shape.

• OccupancyGridPublisher

  • Set IP and Port.

  • Message Type : nav_msgs/OccupancyGrid

  • Default Topic :  /OccupancyGrid

    • After configuring the network, clicking Connect will publish a ROS message.

Occupancy Grid ROS Message

• Ubuntu ROS Setting

  • Run ROS bridge

    • $ roslaunch rosbridge_server rosbridge_websocket.launch

  • Run RQT

    • $ rqt

    • Confirm the published data via RQT.

      • int8[] data : Occupancy Grid data

        • Pedestrian: 10

        • Vehicle: 20

        • Road and Infrastructure: 70

        • ETC: 100

The values of Height and Width are equal to twice the number of cells per row/column.