Data Collection for Camera intrinsic Calibration
Last updated
Last updated
Checkerboard of more than two horizontal inner corners and vertical inner corners. You can use the attached pdf. It has seven internal corners horizontally and nine internal corners vertically. https://drive.google.com/file/d/1mTR8HTpvROE1Pv0rmXEBVLSxs_yMDnvf/view?usp=sharing
Charucoboard of more than two horizontal and vertical squares. Click here for supported Charuco dictionaries.
Place the checkerboard in the field of view of the camera and make sure the checkerboard is in the camera's focus. Move the checkerboard or the camera to different positions and take images so that the coverage of the checkerboard in the camera's field of view is as high as possible. While moving the checkerboard or camera, it is necessary that the entire checkerboard is present in the camera's field of view. In addition, the checkerboard should be tilted slightly in different directions for each image. Do not move the board or the camera while taking the images. Also, do not hold the checkerboard by hand to minimize blur due to shaking. You can also use a computer monitor instead of a physical checkerboard for intrinsic calibration. Monitors are very accurate and flat. You can show this PDF file on the monitor for calibration.
Place the charucoboard in the field of view of the camera and make sure the charucoboard is in the camera's focus. Move the charucoboard or the camera to different positions and take images so that the coverage of the charucoboard in the camera's field of view is as high as possible. While moving the charucoboard or camera, it is not necessary that the entire charucoboard is present in the camera's field of view. In addition, the charucoboard should be tilted slightly in different directions for each image. Do not move the board or the camera while taking the images. Also, do not hold the charucoboard by hand to minimize blur due to shaking. You can also use a computer monitor instead of a physical charucoboard for intrinsic calibration. Monitors are very accurate and flat. Please visit our website to download charucoboard: https://calibrate.deepen.ai/target-generator
For cameras with high distortions, such as fisheye and wide-angle cameras, we need to pay special attention to the field of distortion. If each board only covers a small portion of the image, it is likely to lead to overfitting of the field of distortion. i.e. Locally correct distortion but globally incorrect distortion. We recommend to have at least one image where the board covers most of the field of view. It can give useful information on the distortion across the entire field of view.
For cameras with long focal length and narrow (<= 30 degree) field-of-view, it is difficult to obtain the focal length and principal point accurately. If all boards face the camera almost directly, there may be large errors in the vanishing points and focal length. We need some images where the board is very tilted to obtain accurate vanish points, focal length, and principal point.
