Checkerboard calibration¶

This function uses images of checkerboards to correct distortions introduced by cameras. The checkerboard calibration works best with > 10 checkerboard images at different angles to the camera and in different areas of the field of view.

plantcv.transform.checkerboard_calib(img_path, col_corners, row_corners, out_dir)

returns mtx, dist

• Parameters:

  • img_path - a path to a directory of checkerboard images
  • col_corners - the number of inner corners in a column of the checkerboard
  • row_corners - the number of inner corners in a row of the checkerboard
  • out_dir - directory where the output files will be saved

• Context:

  • Used to create calibration matrices for camera calibration
  • Outputs can be passed to plantcv.transform.calibrate_camera for distortion corrections

• Example use:

Checkerboard image example

Checkerboard calibration

from plantcv import plantcv as pcv

# Set global debug behavior to None (default), "print" (to file), or "plot" (Jupyter Notebooks or X11)
pcv.params.debug = "plot"

# Create calibration matrices with checkerboard images
mtx, dist = pcv.transform.checkerboard_calib(img_path = "./img_files/", col_corners = 13, row_corners = 19, out_dir = "./output/")

# Correct distortions using the outputs from checkerboard calibration
corrected_img = pcv.transform.calibrate_camera(rgb_img = img, mtx_filename = "./output/mtx.npz", dist_filename = "./output/dist.npz")

Source Code: Here