PCL Remove Outliers

 #include <pcl/filters/statistical_outlier_removal.h>  
 #include <pcl/filters/extract_indices.h>  
 inline void RemoveOutliers(std::vector<std::vector<double> > pts, std::vector<std::vector<double> >& pts_out, std::vector<int >& indices)  
 {  
  pcl::PointCloud<pcl::PointXYZ>::Ptr cloud(new pcl::PointCloud<pcl::PointXYZ>);  
  cloud->width=pts.size();  
  cloud->height=1;  
  cloud->points.resize(cloud->width*cloud->height);  
  for(int i=0;i<cloud->points.size();i++)  
  {  
   cloud->points[i].x=pts[i][0];  
   cloud->points[i].y=pts[i][1];  
   cloud->points[i].z=pts[i][2];  
  }  
  pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_filtered (new pcl::PointCloud<pcl::PointXYZ>);  
  pcl::StatisticalOutlierRemoval<pcl::PointXYZ> sor(true);  
  sor.setInputCloud (cloud);  
  sor.setMeanK (50);  
  sor.setStddevMulThresh (1.0);  
  sor.filter (*cloud_filtered);  
  pts_out.resize(cloud_filtered->points.size());  
  for(int i=0;i<cloud_filtered->points.size();i++)  
  {  
     pts_out[i].resize(3);  
     pts_out[i][0]=cloud_filtered->points[i].x;  
     pts_out[i][1]=cloud_filtered->points[i].y;  
     pts_out[i][2]=cloud_filtered->points[i].z;  
  }  
  pcl::IndicesConstPtr ind=sor.getRemovedIndices();  
  pcl::PointIndices::Ptr removed_indices (new pcl::PointIndices());  
  removed_indices->indices = *ind;  
  indices.resize(removed_indices->indices.size());  
  for(int i=0;i<removed_indices->indices.size();i++)  
  {  
   indices[i]=removed_indices->indices[i];  
  }  
 }  

3D rotation matrix composition and decomposition

Decomposition

theta_x=atan2(mat(3,2),mat(3,3));
theta_y=atan2(-mat(3,1),sqrt(mat(3,2)*mat(3,3)));
theta_z=atan2(mat(2,1),mat(1,1));
param=[theta_x,theta_y,theta_z,mat(1,4),mat(2,4),mat(3,4)];

Composition:

T1=cos(y)*cos(z);
T2=cos(z)*sin(x)*sin(y)-cos(x)*sin(z);
T3=cos(x)*cos(z)*sin(y)+sin(x)*sin(z);
T5=cos(y)*sin(z);
T6=cos(x)*cos(z)+sin(x)*sin(y)*sin(z);
T7=-cos(z)*sin(x)+cos(x)*sin(y)*sin(z);
T9=-sin(y);
T10=cos(y)*sin(x);
T11=cos(x)*cos(y);

All in matlab code.

matlab loop through folder

 function [ flag ] = CropAll( folder_name,h )  
 files=dir(strcat(folder_name,'/*.png'));  
 for i=1:numel(files)  
   file_name=files(i).name;  
   img=imread([folder_name,'/',file_name]);  
   img2=img(1:h,:,:);  
   imwrite(img2,[folder_name,'/',file_name]);  
 end  
 flag=1;  
 end  

Some matlab expressions (updating)

1.  remove columns with all zeros

src(:,all(src==0,1))=[];

2. matlab options:

 option=optimset('MaxFunEvals',5000);

Some Latex Exceptions

Recently I want to put some manuscript of mine in arXiv. But it only accepts latex versions.  So I have to re-compile the latex, and there are some errors when I do this, as I was running it on a clean Linux:


1. 

IEEEtran.cls:366: leading text: \normalfont
IEEEtran.cls:724: Font OT1/ptm/m/n/5=ptmr7t at 5.0pt not loadable: Metric (TFM)

install the recommended fonts to fix the problem:

§ sudo apt-get install texlive-fonts-recommended

2. 

Algortihm.sty not found.

Solution: add various algorithm packages by running: sudo apt-get install texlive-science. 

Long Equations in Latex

I recently need to solve some nonlinear least square system, and the equations soon become very complex for an A4 page to display.

Of course you can solve it using eqnarray and show it in multiple lines, but it won't work if the equation cannot be separated, such as it is a long fraction.

I resolve this by adding \small before the equations, and add \normalsize after the equations. Actually, there is something else you can use:

1. \tiny
2. \scriptsize
3. \footnotesize
4. \small
5. \normalsize
6. \large
7. \Large
8. \LARGE
9. \huge
10. \Huge