What is K for fisheye cam?

[Alvin0629]

Hi,

if I want to use cv2.omnidir() function for fisheye undistortion, we need to know K, D and Xi. I see D and Xi in image_02.ymal, but where is the fx and fy in this case? Thanks for your reply!

A.L.

[yiyiliao]

Hi,

I am not familiar with cv2.ominidir() function. Comparing the projectPoints() function of cv2.ominidir(): https://github.com/opencv/opencv_contrib/blob/master/modules/ccalib/src/omnidir.cpp#L143-L165 to our projection function: https://github.com/autonomousvision/kitti360Scripts/blob/master/kitti360scripts/helpers/project.py#L174-L198 I think gamma1 and gamma2 in our code correspond to f[0] and f[1] in their implementation.

Btw, it is important to make sure that both adopt the same camera model, which is true as cv2.ominidir() also adopts the MEI camera model.

Best, Yiyi

[tuanho27]

Hi @Alvin0629, Have you finished testing the undistortion for fisheye image yet? Could you share the example result?

Thanks & BRs, TuanHo

[tuanho27]

Update

I tested the cv2.ominidir() to undistort the image using all given parameters (gamma, Xi, D, u,v), but the rectify output seems stretching at the edge, @yiyiliao do you have any update for this on your side, follow your comment here #39 ?

Thanks a lot, Tuan

[miangoleh]

@tuanho27 Can you share the code you've used?