Camera Calibration

Source: really comprehensive

I have an Arducam B0497 (USB3 8.3MP) which I want to calibrate using a 7x9 checkerboard that I downloaded at www.calib.io. The size is 7x9 with a Checker Size of 20mm. Because the algorithm counts the interior vertex, the size parameter needs to be passed as 8x6.

• First, I had to check what video stream sources I have on Ubuntu through ls \dev\video*. It returned something like this:

• Second, I call v4l2-ctl --device=/dev/video4 --all in the terminal to see what device it represents. For example, video 0 and 1 come from my iPhone’s camera, video 2 and 3 come from my MacBook camera, etc.

• Third, I run gst-launch-1.0 v4l2src device=/dev/video4 ! videoconvert ! autovideosink to check the stream and quality.

• Fourth, I go and modify video_device at sudo nano /opt/ros/noetic/share/usb_cam/launch/usb_cam-test.launch with /dev/video6.
• Fifth, I open 2 new terminals and I call roslaunch usb_cam usb_cam-test.launch and rosrun camera_calibration cameracalibrator.py --size 8x6 --square 0.02 image:=/usb_cam/image_raw camera:=/usb_cam to run the camera_calibrator ROS package.

Files of interest

Camera settings such as port and resolution are found at ~/opt/ros/noetic/share/usb_cam/launch/usb_cam-test.launch and the final matrices returned by the cameracalibrator.py script can be accessed at ~/.ros/camera_info/head_camera.yaml