（1）學(xué)習(xí)如何連接兩個不同點云為一個點云，進行操作前要確保兩個數(shù)據(jù)集中字段的類型相同和維度相等，同時了解如何連接兩個不同點云的字段（例如顏色 法線）這種操作的強制約束條件是兩個數(shù)據(jù)集中點的數(shù)目必須一樣，例如：點云A是N個點XYZ點，點云B是N個點的RGB點，則連接兩個字段形成點云C是N個點xyzrgb類型

新建文件concatenate_clouds.cpp? CMakeLists.txt

concatenate_clouds.cpp ：

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#include <iostream>
#include <pcl/io/pcd_io.h>      //io模塊 
#include <pcl/point_types.h>   //數(shù)據(jù)類型intmain (int argc, char** argv)
{if (argc != 2) //提示如果執(zhí)行可執(zhí)行文件輸入兩個參數(shù) -f 或者-p
  {std::cerr << "please specify command line arg '-f' or '-p'" << std::endl;exit(0);}//申明三個pcl::PointXYZ點云數(shù)據(jù)類型，分別為cloud_a, cloud_b, cloud_cpcl::PointCloud<pcl::PointXYZ> cloud_a, cloud_b, cloud_c;//存儲進行連接時需要的Normal點云,Normal (float n_x, float n_y, float n_z)pcl::PointCloud<pcl::Normal> n_cloud_b;//存儲連接XYZ與normal后的點云pcl::PointCloud<pcl::PointNormal> p_n_cloud_c;// 創(chuàng)建點云數(shù)據(jù)//設(shè)置cloud_a的個數(shù)為5cloud_a.width  = 5;cloud_a.height = cloud_b.height = n_cloud_b.height = 1; //設(shè)置都為無序點云cloud_a.points.resize (cloud_a.width * cloud_a.height); //總數(shù)if (strcmp(argv[1], "-p") == 0)   //判斷是否為連接a+b=c(點云連接)
  {cloud_b.width  = 3;cloud_b.points.resize (cloud_b.width * cloud_b.height);}else{n_cloud_b.width = 5; //如果是連接XYZ與normal則生成5個法線（字段間連接）n_cloud_b.points.resize (n_cloud_b.width * n_cloud_b.height);}
//以下循環(huán)生成無序點云填充上面定義的兩種類型的點云數(shù)據(jù)for (size_t i = 0; i < cloud_a.points.size (); ++i){  //cloud_a產(chǎn)生三個點（每個點都有X Y Z 三個隨機填充的值）cloud_a.points[i].x = 1024 * rand () / (RAND_MAX + 1.0f);cloud_a.points[i].y = 1024 * rand () / (RAND_MAX + 1.0f);cloud_a.points[i].z = 1024 * rand () / (RAND_MAX + 1.0f);}if (strcmp(argv[1], "-p") == 0)for (size_t i = 0; i < cloud_b.points.size (); ++i){   //如果連接a+b=c，則cloud_b用三個點作為xyz的數(shù)據(jù)cloud_b.points[i].x = 1024 * rand () / (RAND_MAX + 1.0f);cloud_b.points[i].y = 1024 * rand () / (RAND_MAX + 1.0f);cloud_b.points[i].z = 1024 * rand () / (RAND_MAX + 1.0f);}elsefor (size_t i = 0; i < n_cloud_b.points.size (); ++i){  //如果連接xyz+normal=xyznormal則n_cloud_b用5個點作為normal數(shù)據(jù)n_cloud_b.points[i].normal[0] = 1024 * rand () / (RAND_MAX + 1.0f);n_cloud_b.points[i].normal[1] = 1024 * rand () / (RAND_MAX + 1.0f);n_cloud_b.points[i].normal[2] = 1024 * rand () / (RAND_MAX + 1.0f);}
/*******************************************************************
定義了連接點云會用到的5個點云對象：3個輸入（cloud_a cloud_b 和n_cloud_b）
兩個輸出（cloud_c  n_cloud_c）然后就是為兩個輸入點云cloud_a和 cloud_b或者cloud_a 和n_cloud_b填充數(shù)據(jù)  ********************************************************************/
//輸出Cloud Astd::cerr << "Cloud A: " << std::endl;for (size_t i = 0; i < cloud_a.points.size (); ++i)std::cerr << "    " << cloud_a.points[i].x << " " << cloud_a.points[i].y << " " << cloud_a.points[i].z << std::endl;
//輸出Cloud Bstd::cerr << "Cloud B: " << std::endl;if (strcmp(argv[1], "-p") == 0)for (size_t i = 0; i < cloud_b.points.size (); ++i)std::cerr << "    " << cloud_b.points[i].x << " " << cloud_b.points[i].y << " " << cloud_b.points[i].z << std::endl;else//輸出n_Cloud_bfor (size_t i = 0; i < n_cloud_b.points.size (); ++i)std::cerr << "    " << n_cloud_b.points[i].normal[0] << " " << n_cloud_b.points[i].normal[1] << " " << n_cloud_b.points[i].normal[2] << std::endl;// Copy the point cloud dataif (strcmp(argv[1], "-p") == 0){cloud_c  = cloud_a;cloud_c += cloud_b;//把cloud_a和cloud_b連接一起創(chuàng)建cloud_c  后輸出std::cerr << "Cloud C: " << std::endl;for (size_t i = 0; i < cloud_c.points.size (); ++i)std::cerr << "    " << cloud_c.points[i].x << " " << cloud_c.points[i].y << " " << cloud_c.points[i].z << " " << std::endl;}else{  //連接字段  把cloud_a和 n_cloud_b字段連接 一起創(chuàng)建 p_n_cloud_c)
    pcl::concatenateFields (cloud_a, n_cloud_b, p_n_cloud_c);std::cerr << "Cloud C: " << std::endl;for (size_t i = 0; i < p_n_cloud_c.points.size (); ++i)std::cerr << "    " <<p_n_cloud_c.points[i].x << " " << p_n_cloud_c.points[i].y << " " << p_n_cloud_c.points[i].z << " " <<p_n_cloud_c.points[i].normal[0] << " " << p_n_cloud_c.points[i].normal[1] << " " << p_n_cloud_c.points[i].normal[2] << std::endl;}return (0);
}

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CMakeLists.txt：

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)project(ch2_2)find_package(PCL 1.2 REQUIRED)include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})add_executable (concatenate_clouds concatenate_clouds.cpp)
target_link_libraries (concatenate_clouds ${PCL_LIBRARIES})

編譯執(zhí)行后的結(jié)果，仔細研究看一下就可以看出點云連接和字段間連接的區(qū)別，字段間連接是在行的基礎(chǔ)后連接，而點云連接是在列的下方連接，最重要的就是要考慮維度問題，同時每個點云都有XYZ三個數(shù)據(jù)值

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字段間連接：

?點云連接

（2）對于獲取傳感器的深度信息可以使用OpenNI Grabber類，（其中涉及到如何安裝傳感器的驅(qū)動等問題，比如我使用的是kinect 1.0 可能會遇到一些安裝問題，但是網(wǎng)上還是有很多的解決辦法的，在這里不對于敘述）

新建文件openni_grabber.cpp

#include <pcl/point_cloud.h>   //點云類定義頭文件
#include <pcl/point_types.h>    //點 類型定義頭文件
#include <pcl/io/openni_grabber.h>  //OpenNI數(shù)據(jù)流獲取頭文件
#include <pcl/common/time.h>         //時間頭文件//類SimpleOpenNIProcessor  的回調(diào)函數(shù)，作為在獲取數(shù)據(jù)時，對數(shù)據(jù)進行處理的回調(diào)函數(shù)的封裝，在本例中并沒有什么處理，只是實時的在標準輸出設(shè)備打印處信息。
class SimpleOpenNIProcessor
{
public:void cloud_cb_ (const pcl::PointCloud<pcl::PointXYZRGBA>::ConstPtr &cloud){static unsigned count = 0;static double last = pcl::getTime ();  //獲取當前時間if (++count == 30)      //每30ms一次輸出
    {double now = pcl::getTime ();//  >>右移std::cout << "distance of center pixel :" << cloud->points [(cloud->width >> 1) * (cloud->height + 1)].z << " mm. Average framerate: " << double(count)/double(now - last) << " Hz" <<  std::endl;count = 0;last = now;}}void run (){pcl::Grabber* interface = new pcl::OpenNIGrabber();  //創(chuàng)建OpenNI采集對象// 定義回調(diào)函數(shù)boost::function<void (const pcl::PointCloud<pcl::PointXYZRGBA>::ConstPtr&)> f =boost::bind (&SimpleOpenNIProcessor::cloud_cb_, this, _1);boost::signals2::connection c = interface->registerCallback (f);//注冊回調(diào)函數(shù)interface->start ();   //開始接受點云數(shù)據(jù)//直到用戶按下Ctrl -cwhile (true)boost::this_thread::sleep (boost::posix_time::seconds (1));//   停止采集interface->stop ();}
};int main ()
{SimpleOpenNIProcessor v;v.run ();return (0);
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)project(openni_grabber)find_package(PCL 1.2 REQUIRED)include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})add_executable (openni_grabber openni_grabber.cpp)
target_link_libraries (openni_grabber ${PCL_LIBRARIES})

編譯后執(zhí)行可執(zhí)行文件的結(jié)果如下

微信公眾號號可掃描二維碼一起共同學(xué)習(xí)交流

未完待續(xù)*******************************************8

總結(jié)

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