Sensor Configuration

Stereo Camera: Custom Underwater Stereo Camera
Doppler Velocity Log: WaterLinked A50 DVL
IMU: MICROSTRAIN 3DM-GX5-AHRS IMU
Depth Sensor: Blue Robotics Bar 30 Pressure/Depth

The sensor frames are defined as follows:

Note that the actual extrinsic parameters between the sensors may vary slightly due to the mounting process. Please refer to the provided parameter files for accurate extrinsic calibration.

Sensor frames side view Sensor frames top view

Data Format

All data is provided by ROS bag and raw data associated with parameter YAML files.

ROS Bag

Topic	Type	Description	HZ
/camera/left/ image_dehazed/compressed	`sensor_msgs/CompressedImage`	Left image from the stereo cameras.	20
/camera/right/ image_dehazed/compressed	`sensor_msgs/CompressedImage`	Right image from the stereo cameras.	20
/imu/data	`sensor_msgs/Imu`	IMU data.	333
/dvl/data	`waterlinked_a50_ros_driver/DVL`	DVL data.	5
/depth/data	`nav_msgs/Odometry`	Depth data from pressure sensor.	30
/apriltag_slam/GT	`nav_msgs/Odometry`	GT pose provided by AprilTag SLAM.	20
/apriltag_slam/GT_full	`nav_msgs/Odometry`	Full ground truth pose fused by AprilTag SLAM and AQUA SLAM.	2.5
/aqua_slam/pose	`nav_msgs/Odometry`	Pose estimate from AQUA SLAM.	2.5

Please note that the /apriltag_slam/GT_full topic is not available in Structure_Easy, Medium and Hard sequences. Since /apriltag_slam/GT already provides high-accuracy full ground truth trajectories, the fusion with AQUA SLAM is not necessary for these sequences.

Raw Data

In addition to the ROS bag files, we provide a Raw Data Conversion Script to extract the raw data from the ROS bag.

The raw data includes the images from the stereo camera, the depth data from the pressure sensor, the DVL data, the IMU data, and the GT data. An example of the folder structure of Structure_Easy sequence is shown as follows:

Parameter file

The parameter files provide the camera’s intrinsic parameters and the extrinsic parameters between the sensors in YAML format.

Please note the extrinsic parameters may vary slightly for different sequences due to the mounting process. Please use the corresponding parameter files for different sequences.

#Camera Intrinsics
Camera.fx: 655.0
Camera.fy: 655.0
Camera.cx: 306.0
Camera.cy: 256.0

# stereo baseline times fx
Camera.bf: 78.89165891925023

# Sensor Extrinsic between IMU and Camera
T_imu_camera: !!opencv-matrix
  rows: 4
  cols: 4
  dt: f
  data: [ -0.0165,   -0.0175,   -0.9997,   -0.211687435,
          -0.0106,    0.9998,   -0.0173,    -0.097259169,
          0.9998,    0.0103,   -0.0167,    -0.056238089,
          0,  0,   0,    1 ]

# Sensor Extrinsic between DVL and Camera    
T_dvl_camera: !!opencv-matrix
  rows: 4
  cols: 4
  dt: f
  data: [ -0.0030,    0.0292,    0.9996,   0.132344740,
          0.9995,    0.0328,    0.0021,    0.032085643,
          -0.0327,    0.9990,   -0.0293,    -0.240100175,
          0,  0,   0,    1 ]

          