teaser and loop closure in MULLS

[chengwei0427]

hi, @YuePanEdward ,thanks for your hardwork!
I didn't find the loop closure in your code ,Is it not finished yet? Or maybe I didn't find!
I want to know how your loop closure detects works , is it work likes the mulls_reg(scan-to-scan) moudle, use teaser to get coarse registration, then use lls to get the refine result?

Thanks!

[YuePanEdward]

Thank you a lot for the feedback.
The loop closure module has already been invloved in MULLS.
The processing unit is submap. It works as the submap-to-submap registration. TEASER provides the initial guess and then LLS refine the result. TEASER is quite fast (10-20ms) and certificable. If TEASER fails, the loop closure edge would be rejected.
You can enable the loop closure by setting --loop_closure_detection_on=true in the config file. The prerequisite is that TEASER is properly installed.

[chengwei0427]

sorry for taking your time.
I'm trying to run the mulls_reg now ,however,when the program run into "creg.mm_llu_icp", there will be an error as follows:
Segmentation fault (core dumped)

the debug core

the test data
data.zip

[YuePanEdward]

Thanks for your feedback.
I've tried mulls_reg on your data and it works from my side.

feature points extracted from target (left) and source (right) point cloud

Point cloud before (left) and after (right) mulls_icp registration

For your issue, It's a bit strange that a segfault occur after the output of final transformation matrix. It seems that there's some problem of the automatic free up of the smart pointer.
So maybe you can add the following lines in the end of mm_lls_icp and see if it would work.

	        LOG(INFO) << "Final tran. matrix:\n"
				  << registration_cons.Trans1_2;
        
		//free mannually
		corrs_ground.reset(new pcl::Correspondences);
		corrs_pillar.reset(new pcl::Correspondences);
		corrs_beam.reset(new pcl::Correspondences);
		corrs_facade.reset(new pcl::Correspondences);
		corrs_roof.reset(new pcl::Correspondences);
		corrs_vertex.reset(new pcl::Correspondences);

		return process_code;

[chengwei0427]

I'm sorry to reply you so late, I'm debugging the core dumped problem.
I want you to know that ,the problem disappeared after re-build Eigen(3.3.9) and pcl(1.9.1),now I can run your program in my pc.
Thank you very much.