I have a dataset published by NIST

<

https://www.nist.gov/pml/engineering-physics-division/dimensional-metrology/algorithm-testing>

(reference datset) to compare the least square algorithms with their

reference dataset for verification purposes. PCL does not have least square

but it has RANSAC which removes the outliers and then compute the least

square. To compare the results of PCL with NIST dataset, I set a high

threshold, so RANSAC would consider all data points as inliner which

bascially turns RANSAC to a least square algorithm. The results of this

comparision is pretty interesting. For some datset PCL reports exactly the

same results that I expect from NIST dataset, but for some other dataset (I

uploaded them here), the results are very different. Can anybody explain to me why

they are different ? Iuse pcl::SACMODEL_CIRCLE3D as my model and

pcl::SAC_RANSAC as my method. cir3.ds

<

http://www.pcl-users.org/file/t499024/cir3.ds> cir3.fit

<

http://www.pcl-users.org/file/t499024/cir3.fit>

instructionsfornist-l2-reference-pairs.pdf

<

http://www.pcl-users.org/file/t499024/instructionsfornist-l2-reference-pairs.pdf>

I attach the reference dataset to this post. The file with .DS extension

includes X, Y, Z of the 400 points, and the file with .FIT includes the

result of fitting. The last number in the .FIT file is the diameter of the

least square fit circle. For this dataset that I uploaded, PCL computes the

diameter = 356.697

and NIST diameter = 361.80966768000886515

Can anybody explain to me why they are so different?

It would be great if someone can fit a circle to their dataset using PCL and let us know their results.

Thank you

--

Sent from:

http://www.pcl-users.org/_______________________________________________

PCL-users@pointclouds.org /

http://pointclouds.orghttp://pointclouds.org/mailman/listinfo/pcl-users