Yaml formats

###Camera-system calibration file (camchain.yaml) This YAML file includes the complete parameter set for the calibration of the camera intrinsic and extrinsic parameters as well as the spatial and temporal calibration parameters of the IMU with respect to the cameras.

Each camera has the following parameters:

• camera_model
  camera projection type (pinhole / omni)
• intrinsics
  vector containing the intrinsic parameters for the given projection type. elements are as follows:
  pinhole: [fu fv pu pv]
  omni: [xi fu fv pu pv]
  see Supported models for more information
  
• distortion_model
  lens distortion type (radtan / equidistant)
  
• distortion_coeffs
  parameter vector for the distortion model
  see Supported models for more information
  
• T_cn_cnm1
  extrinsic parameters, always with respect to the last camera in the chain
  (e.g. cam1: T_cn_cnm1 = T_c1_c0)
  
• T_cam_imu
  IMU extrinsics: tranformation from IMU-frame to camera frame
  
• timeshift_cam_imu
  timeshift between camera and IMU timestamps in seconds (t_imu = t_cam + shift)
  
• rostopic
  topic of the camera's image stream
• resolution
  camera resolution [width,height]

Example chain.yaml

cam0:
  camera_model: pinhole
  intrinsics: [461.629, 460.152, 362.680, 246.049]
  distortion_model: radtan
  distortion_coeffs: [-0.27695497, 0.06712482, 0.00087538, 0.00011556]
  T_cam_imu:
  - [0.01779318, 0.99967549,-0.01822936, 0.07008565]
  - [-0.9998017, 0.01795239, 0.00860714,-0.01771023]
  - [0.00893160, 0.01807260, 0.99979678, 0.00399246]
  - [0.0, 0.0, 0.0, 1.0]
  timeshift_cam_imu: -8.121e-05
  rostopic: /cam0/image_raw
  resolution: [752, 480]
cam1:
  camera_model: omni
  intrinsics: [0.80065662, 833.006, 830.345, 373.850, 253.749]
  distortion_model: radtan
  distortion_coeffs: [-0.33518750, 0.13211436, 0.00055967, 0.00057686]
  T_cn_cnm1:
  - [ 0.99998854, 0.00216014, 0.00427195,-0.11003785]
  - [-0.00221074, 0.99992702, 0.01187697, 0.00045792]
  - [-0.00424598,-0.01188627, 0.99992034,-0.00064487]
  - [0.0, 0.0, 0.0, 1.0]
  T_cam_imu:
  - [ 0.01567142, 0.99978002,-0.01393948,-0.03997419]
  - [-0.99966203, 0.01595569, 0.02052137,-0.01735854]
  - [ 0.02073927, 0.01361317, 0.99969223, 0.00326019]
  - [0.0, 0.0, 0.0, 1.0]
  timeshift_cam_imu: -8.681e-05
  rostopic: /cam1/image_raw
  resolution: [752, 480]

###IMU configuration Each IMU in the calibration is configured using a YAML file. Please refer to the example below for details:

imu.yaml

#Accelerometers
accelerometer_noise_density: 0.006  #Noise density (continuous-time) [UNIT]
accelerometer_random_walk:   0.0002 #Bias random walk [UNIT]

#Gyroscopes
gyroscope_noise_density:     0.0004  #Noise density (continuous-time) [UNIT]
gyroscope_random_walk:       4.0e-06 #Bias random walk [UNIT]

update_rate:                 200.0 #Hz (for discretization of the values above)

TODO: INSERT UNITS ABOVE!

###Calibration target configuration Please refer to the Calibration targets page.