YAC - Yet Another Calibrator

Yet Another Calibrator (YAC) is a calibration tool for calibrating RGB cameras. Specifically:

• Camera intrinsics and extrinsics
• Camera-IMU extrinsic
• Mocap-marker to camera extrinsics

Supported projection-distortion models:

• pinhole-radtan4
• pinhole-equi4

Dependencies

# Ubuntu packages
libyaml-cpp-dev
libeigen3-dev
libceres-dev
libopencv-dev
libomp-dev (optional)

# Custom (see deps dir)
Modified apriltags (https://github.com/chutsu/apriltags)

Build

For the lazy :

git clone https://github.com/chutsu/yac
cd yac
make deps
make lib

Or standard approach:

git clone https://github.com/chutsu/yac
cd yac
mkdir -p build
cd build
cmake .. -DCMAKE_BUILD_TYPE=Release
make

Calibration Target

yac uses a grid of AprilTags, a.k.a an AprilGrid, as a calibration target.

Click here to download and print the AprilGrid. During data collection make sure the calibration target is as flat as possible.

Setting up the Calibration Configuration File

First inorder to calibrate a camera or camera-IMU we need to create the calibration configuration file. For example calib_intel_d435i.yaml configuration file:

calib_target:
  target_type: 'aprilgrid'  # Target type
  tag_rows: 6               # Number of rows
  tag_cols: 6               # Number of cols
  tag_size: 0.088           # Size of apriltag, edge to edge [m]
  tag_spacing: 0.3          # Ratio of space between tags to tagSize
                            # Example: tag_size=2m, spacing=0.5m
                            #          --> tag_spacing=0.25[-]

cam0:
  proj_model: "pinhole"
  dist_model: "radtan4"
  resolution: [640, 480]

cam1:
  proj_model: "pinhole"
  dist_model: "radtan4"
  resolution: [640, 480]

Run the Calibration

calib_camera <path to config file> <path to data>
calib_vi <path to config file> <path to data>

LICENCE

MIT