Values for Camera Model with Distortion

In the “Edit Camera Model” for the “Camera Model with Distortion” drop-down list, there are three values 0, 3, and 5.  I could not find any explanation for these in the online manual and just curious for which scenario that a value should be selected?

Dear Chu,

This refers to the number of parameters in the distortion model. For example, there are both tangential and radial distortion parameters. You can find more information about these parameters here

https://support.pix4d.com/hc/en-us/articles/202559089-How-are-the-Internal-and-External-Camera-Parameters-defined-#gsc.tab=0

5 is the default, 3 would only correct for the radial distortions, and 0 would not correct for distortions. It is recommended to keep the default. 

Best regards,

Thank you for your response.  So for a perspective lens:

0: no distortion parameters.

3: R1, R2, R3 radial distortion coefficients.

5: R1, R2, R3 radial and T1, T2 the tangential distortion coefficients.