Configure Iterative Closest Point PCL - android-ndk

Question

I am having trouble configuring ICP in PCL 1.6(I use Android) and I believe that is the cause of an incorrect transformation matrix. What I've tried so far is this;
Downsample the point clouds I use in ICP with the following code:
pcl::VoxelGrid <pcl::PointXYZ> grid;
grid.setLeafSize(6, 6, 6);
grid.setInputCloud(output);
grid.filter(*tgt);
grid.setInputCloud(cloud_src);
grid.filter(*src);
Try to align the two point clouds with the following code :
pcl::IterativeClosestPoint<pcl::PointXYZ, pcl::PointXYZ> icp;
icp.setInputCloud(tgt);
icp.setInputTarget(src);
pcl::PointCloud<pcl::PointXYZ> Final;
pcl::PointCloud<pcl::PointXYZ> transformedCloud;
icp.setMaxCorrespondenceDistance(0.08);
icp.setMaximumIterations(500);
//icp.setTransformationEpsilon (0.000000000000000000001);
icp.setTransformationEpsilon(1e-12);
icp.setEuclideanFitnessEpsilon(1e-12);
icp.setRANSACIterations(2000);
icp.setRANSACOutlierRejectionThreshold(0.6);
I have tried all kinds of values in the options of ICP but with no success.
The code I use to create the point cloud:
int density = 1;
for (int y = 0; y < depthFrame.getHeight(); y = y + density) {
for (int x = 0; x < depthFrame.getWidth(); x = x + density) {
short z = pDepthRow[y * depthVideoMode.getResolutionX() + x];
if (z > 0 && z < depthStream.getMaxPixelValue()) {
cloud_src->points[counter].x = x;
cloud_src->points[counter].y = y;
cloud_src->points[counter].z = z;
}
}
}
Any chance somebody can help me out configuring ICP?

Answer 1

From what I know, PCL uses meters as a unit of measurement. so, is it intended that leaf size for downsampling is 6*6*6 !? I think it's huge !!
Try with some lower values and if it didn't work either, try ICP with the most simple configuration as follows :
pcl::IterativeClosestPoint<pcl::PointXYZ, pcl::PointXYZ> icp;
icp.setInputCloud(tgt);
icp.setInputTarget(src);
pcl::PointCloud<pcl::PointXYZ> Final;
icp.align(Final);
once, you got this working (and it should be), then start tuning the other parameters and it shouldn't be that hard to do.
Hope that helps, Cheers!