Get outliers from PCL sample consensus - c++

Question

I am using the functionality for SampleConsensus provided by PCL as per the example here: http://pointclouds.org/documentation/tutorials/random_sample_consensus.php#random-sample-consensus
The question is, the implementation allows for the retrieval of ransac inliers through the use of getInliers this can then be easily transferred into a point cloud using the common function copyPointCloud(in, inliers, out). I am interested in looking at the outliers. There doesnt seem to be functionality to return a list of outliers. If the inlier list is sorted then I could loop through the point list and check against the current inlier as so:
for i in point cloud
if i == currentInlier
currentInlier++
else
add point cloud (i) to new outlier cloud
But I am not sure that the inlier list is guaranteed to be sorted even though it seems like it would be created that way?
Also surely there is a native way to do this in PCL?

Answer 1

You almost certainly want pcl::ExtractIndices. It is documented here:
http://docs.pointclouds.org/1.7.0/classpcl_1_1_extract_indices.html
You can see how it is used here:
http://pointclouds.org/documentation/tutorials/extract_indices.php#extract-indices
See in particular:
pcl::ExtractIndices<pcl::PointXYZ> extract;
...
extract.setInputCloud (cloud_filtered);
extract.setIndices (inliers);
...
extract.setNegative (true);
extract.filter (*cloud_f);