The extrinsic calibration matrix between aux camera and left camera

[anakita]

Hi, I am trying to access the extrinsic calibration matrix between the left rectified image and the aux rectified color image. Is it published on any ros topic or is there a way to access this matrix for multisense S30?

Thank you

[mattalvarado]

Hi @anakita,

You can get the extrinsic calibration matrix from the /multisense/aux/image_rect/camera_info topic. Specifically the P matrix https://docs.carnegierobotics.com/docs/calibration/stereo.html#p-matrix from that camera info topic contains the Tx, Ty, and Tz extrinsics translation parameters. It's worth noting that the rectification process makes all the rectified images coplanar, so the rotation between the left rectified, aux rectified, and right rectified coordinate frames are all identity.

The extrinsics transform information is also dynamically populated in the published /tf network. Looking up the transform between the multisense/left_camera_optical_frame and the multisense/aux_camera_optical_frame will give you the transform matrix you are looking for.

[anakita]

Hi @mattalvarado , Thank you for the reply. I will check out the link.

[mattalvarado]

You can use the TF2 listener tutorials as a reference for doing the transform lookup between the multisense/left_camera_optical_frame and the multisense/aux_camera_optical_frame frames.