PCL点云文件生成与读取

提要

     PCL中创造了一种用于描述空间点集的文件  -  PCD.关于PCD的简介，可以参考这里 - http://pointclouds.org/documentation/tutorials/pcd_file_format.php

今天要做的是最简单的事情 - PCD文件的生产与读取。

环境：Win7 64bit VS2010 PCL1.7

PCL编译参考这里 - Window7下手动编译最新版的PCL库

PCD文件生成

     官网推荐的是用cmake来管理工程，在windows中，我们可以通过Cmakegui来生成VS2010的工程，然后导入。这样就免去了在VS中各种添加lib，头文件之苦了 ^^

     首先创建主程序 pcd_write.cpp ，随便找个记事本写一下就可以了，代码如下：

 #include
 #include
 #include
 #include
 #include
 using namespace std;


 int main (int argc, char** argv)
 {
   pcl::PointCloud cloud;
   // Fill in the cloud data
   cloud.width    = 5;
   cloud.height   = 1;
   cloud.is_dense = false;
   cloud.points.resize (cloud.width * cloud.height);

   for (size_t i = 0; i < cloud.points.size (); ++i)
   {
     cloud.points[i].x = 1024 * rand () / (RAND_MAX + 1.0f);
     cloud.points[i].y = 1024 * rand () / (RAND_MAX + 1.0f);
     cloud.points[i].z = 1024 * rand () / (RAND_MAX + 1.0f);
   }

   pcl::io::savePCDFileASCII ("test_pcd.pcd", cloud);
   std::cerr << "Saved " << cloud.points.size () << " data points to test_pcd.pcd." << std::endl;

   for (size_t i = 0; i < cloud.points.size (); ++i)
     std::cerr << "    " << cloud.points[i].x << " " << cloud.points[i].y << " " << cloud.points[i].z << std::endl;

   getchar();
   return (0);
 }

再创建CMakeLists.txt

 cmake_minimum_required(VERSION 2.6 FATAL_ERROR)
 project(MY_GRAND_PROJECT)
 find_package(PCL 1.3 REQUIRED COMPONENTS common io)
 include_directories(${PCL_INCLUDE_DIRS})
 link_directories(${PCL_LIBRARY_DIRS})
 add_definitions(${PCL_DEFINITIONS})
 add_executable(pcd_write_test pcd_write.cpp)
 target_link_libraries(pcd_write_test ${PCL_COMMON_LIBRARIES} ${PCL_IO_LIBRARIES})

在工程目录下创建一个build文件夹，接下来打开CMake-gui，将CMakeList.txt托进去，Configure->Generate.如果环境是配置好的话，结果就像这样：

如果报错了，基本是你环境没配置好，检查一下该装的东西是否都安装好了，环境变量是否设置好。

成功时候在build文件夹下就生成了对应的vs2010工程了，直接双击打开 MY_GRAND_PROJECT.sln

导入后在cloud_view上 右击->Set as StartUp Project,如下图：

直接运行，效果如下：

工程目录下就生成了一个 test_pcd.pcd 点云文件。

点云文件的读取

套路和上面的一样，贴一下代码就好。

cloud_viewer.cpp

 #include
 #include
 #include
 #include

 int user_data;

 void
 viewerOneOff (pcl::visualization::PCLVisualizer& viewer)
 {
     viewer.setBackgroundColor (0.0, 0.0, 0.0);
     pcl::PointXYZ o;
     o.x = 1.0;
     o.y = 0;
     o.z = 0;
     viewer.addSphere (o, 0.25, "sphere", 0);
     std::cout << "i only run once" << std::endl;

 }

 void
 viewerPsycho (pcl::visualization::PCLVisualizer& viewer)
 {
     static unsigned count = 0;
     std::stringstream ss;
     ss << "Once per viewer loop: " << count++;
     viewer.removeShape ("text", 0);
     viewer.addText (ss.str(), 200, 300, "text", 0);

     //FIXME: possible race condition here:
     user_data++;
 }

 int
 main ()
 {
     pcl::PointCloud::Ptr cloud (new pcl::PointCloud);
     pcl::io::loadPCDFile ("bunny.pcd", *cloud);

     pcl::visualization::CloudViewer viewer("Cloud Viewer");

     //blocks until the cloud is actually rendered
     viewer.showCloud(cloud);

     //use the following functions to get access to the underlying more advanced/powerful
     //PCLVisualizer

     //This will only get called once
     viewer.runOnVisualizationThreadOnce (viewerOneOff);

     //This will get called once per visualization iteration
     viewer.runOnVisualizationThread (viewerPsycho);
     while (!viewer.wasStopped ())
     {
     //you can also do cool processing here
     //FIXME: Note that this is running in a separate thread from viewerPsycho
     //and you should guard against race conditions yourself...
     user_data++;
     }
     return 0;
 }

CMakeLists.txt

 cmake_minimum_required(VERSION 2.8 FATAL_ERROR)

 project(cloud_viewer)

 find_package(PCL 1.2 REQUIRED)

 include_directories(${PCL_INCLUDE_DIRS})
 link_directories(${PCL_LIBRARY_DIRS})
 add_definitions(${PCL_DEFINITIONS})

 add_executable (cloud_viewer cloud_viewer.cpp)
 target_link_libraries (cloud_viewer ${PCL_LIBRARIES})

将刚才生成的pcd文件拷贝过来，运行的结果如下：

由于之前生成的pcd里面仅有一些离散的点，看的不是很明显，加载一个Stanford bunny 的点云（PCL目录下有）来看看。

参考

Using PCL in your own project - http://pointclouds.org/documentation/tutorials/using_pcl_pcl_config.PHP#using-pcl-pcl-config

讀取 pcd 檔並顯示三維影像 - http://coldnew.github.io/blog/2013/04/12_64cf9.html

The CloudViewer - http://pointclouds.org/documentation/tutorials/cloud_viewer.php#cloud-viewer