In OpenCV.fisheye, What is difference between 'calibrate()' and 'undistortimage()' functions?

Question

I read OpenCV.fisheye official manual, and I'm confused about the use of calibrate() and undistortImage() functions.

I know that both are used to fix some distortion in an image but, it looks too similar to me.

The docs I referred to are:

• https://docs.opencv.org/trunk/db/d58/group__calib3d__fisheye.html
• https://hackaday.io/project/12384-autofan-automated-control-of-air-flow/log/41862-correcting-for-lens-distortions

If you know, explain the difference between them, please share it... :)

Answer 1

calibrate() returns you your camera's intrinsic parameters / distortion coefficients which then can be passed into undistortImage() to correct for the lens warping.