Sensor Calibration Format: ncamera, imu-sigmas

ROVIOLI uses three different calibration files:

  • ncamera_calibration

  • imu_parameters_maplab

  • imu_parameters_rovio

Additionally, the standard config file is required to sit in the same directory as the calibration files. Please consult the rovio Wiki pages for the meaning of the specific parameters.


The ncamera file determines the camera calibration. It can be obtained from tools like Kalibr. E.g., the ncamera file may look like the following:

label: "Euroc - original_calibration"
id: 412eab8e4058621f7036b5e765dfe812
- camera:
    label: cam0
    id: 54812562fa109c40fe90b29a59dd7798
    line-delay-nanoseconds: 0
    image_height: 480
    image_width: 752
    type: pinhole
      cols: 1
      rows: 4
      data: [458.6548807207614, 457.2966964634893, 367.2158039615726, 248.37534060980727]
      type: radial-tangential  
        cols: 1
        rows: 4
        data: [-0.28340811217029355, 0.07395907389290132, 0.00019359502856909603,
    cols: 4
    rows: 4
    data: [0.0148655429818, -0.999880929698, 0.00414029679422, -0.0216401454975,
           0.999557249008, 0.0149672133247, 0.025715529948, -0.064676986768,
          -0.0257744366974, 0.00375618835797, 0.999660727178, 0.00981073058949,
          0.0, 0.0, 0.0, 1.0]


This file contains IMU parameters to be used in maplab. These are used within the bundle adjustment and other console commands. The label field in this file determines the rostopic for data to listen on. The file may look like this:

label: imu0
saturation_accel_max: 150.0
saturation_gyro_max: 7.5
gravity_magnitude: 9.81
    acc_noise_density: 4e-3
    acc_bias_random_walk_noise_density: 4e-3
    gyro_noise_density: 1e-4
gyro_bias_random_walk_noise_density: 1e-4


This file contains the IMU noise parameters to be used within ROVIO. This is only used within ROVIO itself, and not in any console commands. Note, that these values may differ to the ones provided in the maplab file. The ROVIO IMU parameters file may look like this:

acc_noise_density: 1e-4
acc_bias_random_walk_noise_density: 1e-8
gyro_noise_density: 7.6e-7
gyro_bias_random_walk_noise_density: 3.8e-7