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To reduce Laserscan points

Thu, 08/12/2010 - 12:16 — donghwan

I succeeded to Real-time SLAM.

But, I have some troubles to implement ICP-SLAM.

My UTM-30LX has 1081 points about 270 degree!

I think It works bad because points are too many.

It troubles between threshold and minICPgoodnessToAccept.

So! I want to know how do I cut back some points.

thanks, always.

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Thu, 08/12/2010 - 13:25 — jlblanco
jlblanco's picture

Hi, There're two things to do

Hi,

There're two things to do to optimize it regarding the settings of the points map where all the scans are fused (which in the end should be the bottleneck...).
Take a look at the section [MappingApplication_pointsMap_00_insertOpts] in http://browse-code.mrpt.org/stable/share/mrpt/config_files/icp-slam/icp-....

The two parameters to play with are:

minDistBetweenLaserPoints -> If set to 0.10 for example, only 1 point each 10cm will be inserted in the map, even if that discards 100 ranges from the Hokuyo.

fuseWithExisting -> Set to false and insertions in the map will be faster. The bad part is that with time, there will be much more points, but it can be mitigated a bit with the other param above.

Also you can increase the values of:

localizationLinDistance	= 0.2	// The distance threshold for correcting odometry with ICP (meters)  
localizationAngDistance	= 5	// The distance threshold for correcting odometry with ICP (degrees)

if you have odometry, and in all cases you can increase:

insertionLinDistance	= 1.2	// The distance threshold for inserting observations in the map (meters)
insertionAngDistance	= 45.0	// The distance threshold for inserting observations in the map (degrees)

not to insert in the map too many scans.

JL

Tue, 08/17/2010 - 07:43 — donghwan
donghwan's picture

Thanks! but,

Thanks! but, It's not a solution for bad works. Map cracking!

I think it's well first.

But, when a vehicle goes by dint thing like door, the map is cracked and the vehicle's odometry is initialized.

I try to control some parameter in configuration files, but not a solution too.

I suppose it's cracked because its 270 degree. but, I don't know.

I have been reading papers for ICP-SLAM and I'm trying to solve it.
Please give me any advises for it.

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