# VOXL 2 Stereo Calibration

Source: https://forum.modalai.com/topic/1559/voxl-2-stereo-calibration
Category: VOXL 2 and VOXL 2 Mini (https://forum.modalai.com/category/26/voxl-2-and-voxl-2-mini)
Tags: voxl-2
Posted: 2022-11-21 20:19:24 UTC by bendraper
Replies: 7 · Views: 1183

## bendraper · 2022-11-21 20:19:24 UTC

Hi all,

Trying to do a stereo camera calibration on a VOXL 2 and getting pretty large re-projection errors when calibrating the extrinsics but okay error for the individual cameras. Followed the documentation for calibrating the cameras and sifted through the forums but can't seem to find a solution to this. Is there a step to calibrating that isn't specified in the documentation? or is there a best practice for doing these calibrations?  Thanks!

![f87d5bbe-8fb2-4812-8cb5-6546d299bc2f-image.png](https://forum.modalai.com/assets/uploads/files/1669061719883-f87d5bbe-8fb2-4812-8cb5-6546d299bc2f-image.png)

## Reply by bendraper · 2022-11-21 20:40:22 UTC

the actual distance between cameras is about 0.0857 but that is not what it is calculating

## Reply by modaltb (ModalAI staff) · 2023-01-03 20:01:15 UTC

@bendraper ,

Sorry for the lag here, I'm cleaning up open topics and saw this message a bit late....  Any progress on this issue?

## Reply by bendraper · 2023-01-05 19:50:09 UTC (in reply to modaltb)

@modaltb No problem! I think I'm getting close. Im pretty consistently getting a reprojection error ~0.6 at this point so still have yet to successfully calibrate stereo extrinsics. Tried new stereo cams, refocusing, different lighting, different scales of checkerboards, but can't get sub 0.5

## Reply by Cheng Sheng Weng · 2023-01-06 06:54:02 UTC

I also have the same problem.

## Reply by bendraper · 2023-01-06 16:25:55 UTC

Lol today it decided to finally work. error 0.39

## Reply by Adrian Hidalgo (ModalAI staff) · 2023-01-06 17:19:35 UTC (in reply to bendraper)

@bendraper Curious to know if some factors changed from the last time you got the large errors

## Reply by bendraper · 2023-01-06 18:25:14 UTC (in reply to Adrian Hidalgo)

@Adrian-Hidalgo I redesigned the mounting piece for the cameras, used new refocused cameras, and fixed some errors in my general camera extrinsics file (although I'm not sure that last one is related)