Bag format

All applications in Kalibr use ROS bags as a source for the image and IMU data.

How to use ROS2 bag file format?

Kalibr requires ROS1 bags, thus you need to convert your bags. You can follow the ROS2 Calibration Using Kalibr guide or convert through the static files using the below bagcreater.

How to use image files and IMU data as CSV files?

A bagcreater script is provided to use image files and/or IMU data for the calibration

bagcreater

This script allows you to create a ROS bag from raw image files and optionally IMU data. The files have to be organized in folders as illustrated below. The example uses a system with two cameras and one IMU:

+-- dataset-dir
    +-- cam0
    │   +-- 1385030208726607500.png
    │   +--      ...
    │   \-- 1385030212176607500.png
    +-- cam1
    │   +-- 1385030208726607500.png
    │   +--      ...
    │   \-- 1385030212176607500.png
    \-- imu0.csv

The imu0.csv file uses the format below: (timestamps=[ns], omega=[rad/s], alpha=[m/s^2])

timestamp,omega_x,omega_y,omega_z,alpha_x,alpha_y,alpha_z
1385030208736607488,0.5,-0.2,-0.1,8.1,-1.9,-3.3
 ...
1386030208736607488,0.5,-0.1,-0.1,8.1,-1.9,-3.3

To create the ROS bag run the following command:

kalibr_bagcreater --folder dataset-dir/. --output-bag awsome.bag

In the example above the data would be written to the following topics:

• /cam0/image_raw
• /cam1/image_raw
• /imu0

bagextractor

The bagextractor exports a ROS bag containing image and/or IMU data to image files and an IMU CSV file.

Example usage:

kalibr_bagextractor --image-topics /cam0/image_raw /cam1/image_raw --imu-topics /imu0 --output-folder dataset-dir --bag awsome.bag

NOTE: If you are using the Docker container the output-folder should be relative to the /data volume directory which is mounted of launch of the container.