Trying to understand how the optimization parameters work for Lio-mapping

[ghost]

Hey. My question is are follows. What do the following parameters do in the indoor_test_config.yaml file in the lio_mapping package?

optimization options

run_optimization: 1

update_laser_imu: 1 gravity_fix: 1

plane_projection_factor: 0

imu_factor: 1 point_distance_factor: 1

prior_factor: 0

marginalization_factor: 1

odom_io: 6

pcl_viewer: 0

I am especially interested in odom_io as it seems to be affecting the trajectory of my odometry, but I am not sure how it affects it.

Thanks

[hyye]

Hi @SoguMax, thanks for your interest. For some of the parameters you may refer to https://github.com/hyye/lio-mapping/issues/20#issuecomment-514591841. The odom_io is used to skip several frames. For example, odom_io: 2 means that it will take 1 point cloud from every 2 point clouds.

[ghost]

Thank you so much for your help.

On Tue, May 26, 2020 at 5:50 AM Haoyang Ye notifications@github.com wrote:

Hi @SoguMax https://github.com/SoguMax, thanks for your interest. For some of the parameters you may refer to #20 (comment) https://github.com/hyye/lio-mapping/issues/20#issuecomment-514591841. The odom_io is used to skip several frames. For example, odom_io: 2 means that it will take 1 point cloud from every 2 point clouds.

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[ghost]

Hi, @hyye

There seems to be a drift in the z direction when moving and capturing data through several floors in an indoor environment. What do you recommend? Moving the lidar and imu through a faster motion (The bag file is recorded with a slow walking pace) or just adjusting this odom_io parameter.

Thank you

[gisbi-kim]

@SoguMax similar issue. I'm testing in an outdoor environment also z drift occurs,
any advice.. ?

[hyye]

Hi @SoguMax and @kissb2, thanks for your interest. As I mentioned in https://github.com/hyye/lio-mapping/issues/18#issuecomment-513747567, this drift is inevitable if the path is long and of no local loop. Adding a loop detection module, e.g., segmap, and optimize the pose graph may help.