![Page 1: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/1.jpg)
Multiple Lidar Calibration
Surface Registration
Aras AkbariDr.Liam Pedersen
![Page 2: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/2.jpg)
LER (SEV) System Overview
SICK LMS 291 Lidar•70 Hz scan rate •180° range, •0.25° angular resolution
Hokuyo UTM-30LX Lidar•45 Hz scan rate •180° range, •0.25° angular resolution
![Page 3: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/3.jpg)
Problem StatementPoint clouds from different lidars not well aligned using best estimates (digital level)
![Page 4: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/4.jpg)
PHHP itit
w
t
}{},{ PPw
t
w
refdMinimiz
Pos at time t
Laser pose WRT Robot
Point at time t in lidar fram
Optimize
Problem Statement
![Page 5: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/5.jpg)
Surface Registration
ICP: point To point matching
Finding the rotation, translation between two point clouds by solving the orientation problem using Horn's quaternion-based method.
Result :
Reason -> No point to point correspondences.
![Page 6: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/6.jpg)
Terrain Problem The Terrains are different.
*** *
*
**
* * **
*
**
∆t•Time difference •Pose estimator error
![Page 7: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/7.jpg)
Surface Registration
Used Nelder Mead method to minimize the Mahalanobis distance between the corresponding points
PHHHP itite
w
t
)()( 1)(, xxP
TW
txDx
Where is the mean vector and ∑ is the covariance matrix of closets point to x in Pref
![Page 8: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/8.jpg)
Solved globally
PHHP itit
w
t
PHHHP itite
w
t
![Page 9: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/9.jpg)
Multiple Lidar Calibration
Calibrate lidar’s wrt primary:
Pose at time t
reference lidar point set (global coords)
adjusted lidar points (wrt rover) at time t
calibration correction
![Page 10: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/10.jpg)
No calibration target required
But need some verticalrelief.
![Page 11: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/11.jpg)
![Page 12: Multiple Lidar Calibration Surface Registration Aras Akbari Dr.Liam Pedersen](https://reader030.vdocuments.mx/reader030/viewer/2022032607/56813050550346895d95fd9b/html5/thumbnails/12.jpg)
Question ?Question ?? Questions??