k1 distortion parameter for KANNALA_BRANDT camera model?

[sandeepnmenon]

As per OpenCV, the KANNALA_BRANDT mode has the camera parameters named
fx, fy, cx, cy, and distortion parameters as k1, k2, k3 and k4

However, as mentioned in the code in this repo
https://github.com/hengli/camodocal/blob/7211aaf6869c94e5de4696c93ece8ade975a3e56/src/camera_models/EquidistantCamera.cc#L17-29

I understand that mu and mv are fx and fy respectively
Similarly, u0 and v0 are cx and cy respectively.

How about the distortion coefficients? Where is the parameter k1?

[fickrie67]

As per OpenCV, the KANNALA_BRANDT mode has the camera parameters named fx, fy, cx, cy, and distortion parameters as k1, k2, k3 and k4

However, as mentioned in the code in this repo https://github.com/hengli/camodocal/blob/7211aaf6869c94e5de4696c93ece8ade975a3e56/src/camera_models/EquidistantCamera.cc#L17-29

I understand that mu and mv are fx and fy respectively Similarly, u0 and v0 are cx and cy respectively.

How about the distortion coefficients? Where is the parameter k1?

k1 is 1 here