ROS-268-min-valid-cols-lidar-scan

[Samahu]

Related Issues & PRs

• Related Param min packets in cloud #268

Summary of Changes

• Skip the lidar_scan based on a predefined percentage of the minimum number of valid columns in scan

Validation

• Launch a node as usual but enable the new min_scan_valid_columns_ratio parameter (set a high value)

roslaunch ouster_ros driver.launch sensor_hostname:=... min_scan_valid_columns_ratio:=0.9

• Observe the warning messages whenever the number of valid columns drops below the set amount:

[ WARN] [1738283732.021510354]: number of valid columns per scan 160 which is below the ratio 90%% SKIPPING SCAN
[ WARN] [1738283732.080962740]: number of valid columns per scan 304 which is below the ratio 90%% SKIPPING SCAN

[ovaag]

Yep, that's cleaner! Thanks for taking the time to look into this.

If we now wanted to publish this on a rostopic, I guess we could return a std::optional<size_t> from the lidar_packet_handler? Since valid_cols will only be relevant if result = true in lidar_packet_accumlator.

A /ouster/statistics topic sounds good.

Is this something you would be interested in having upstream?

Another options is of course to have the publisher directly in the LidarPacketHandler, but that might differ a bit from how the rest of ros pubs/subs are done?

[Samahu]

If we now wanted to publish this on a rostopic, I guess we could return a std::optional<size_t> from the lidar_packet_handler? Since valid_cols will only be relevant if result = true in lidar_packet_accumlator.

I assume you are talking about publishing valid_cols value to a separate topic

A /ouster/statistics topic sounds good.

If we are moving in this direction, I would say probably /ouster/scan_stats seems more appropriate (unless we can think of something else).

Is this something you would be interested in having upstream?

yeah, I think it makes sense to me to add the param to filter LidarScan based on this PR, I am not sure yet about adding a scan stats or statistics topic yet.

An alternative approach would be to publish the LidarScan to a topic as is, and the let subscribed nodes do the PointCloud2 scan decoding on their own, this would be a major work that I can not take on in the near term.

[matthew-lidar]

One small thing about the warning print, otherwise looks good!