写在前面：生成点云前提是已经安装好了libfreenect2和PCL，网上有许多这方面的大把教程，在这里就不多赘述了。
-->ubuntu16.04，pcl1.8<--

0，工件的点云展示

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1，实现步骤

• 先通过libfreenect2提供的getPointXYZRGB函数，得到图像中每个像素点的空间坐标xyz以及rgb值。
  

  

• 运用点云库PCL中点云可视化功能，将获取到的每个点的xyz和rgb显示出来。

点云显示关键代码：

1，pcl::visualization::CloudViewer viewer ("Viewer"); //创建一个显示点云的窗口，命名为Viewer。
2，PointCloud::Ptr cloud ( new PointCloud ); //使用智能指针，创建一个空点云。这种指针用完会自动释放。
这个空点云必须创建在while循环里面，否则最后显示出来的画面会无限叠加在窗口上，会变得很卡，之前写在了外面，找了好久才找到原来是这里写错了！
2，PointT p;//定义一个用于储存坐标信息的点
3，cloud->points.push_back( p );//将点P存入cloud
4，viewer.showCloud (cloud);//将cloud可视化

注意：将下列两个文件复制到同一个文件夹中，并在终端中依次执行cmake .，make,便会生成一个可执行文件main，输入./main，就可以显示点云，如果是一片漆黑，是因为我在代码中设置了点云的范围，将if语句去掉即可。

2，main.cpp

#include <iostream>
#include <stdio.h>
#include <iomanip>
#include <time.h>
#include <signal.h>
#include <opencv2/opencv.hpp>
#include <math.h>

#include <libfreenect2/libfreenect2.hpp>
#include <libfreenect2/frame_listener_impl.h>
#include <libfreenect2/registration.h>
#include <libfreenect2/packet_pipeline.h>
#include <libfreenect2/logger.h>
 

#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
#include <pcl/visualization/cloud_viewer.h>
#include <pcl/visualization/pcl_visualizer.h>
#include <pcl/point_cloud.h>

using namespace std;
using namespace cv;


typedef pcl::PointXYZRGBA PointT;
typedef pcl::PointCloud<PointT> PointCloud;



enum
{
    Processor_cl,
    Processor_gl,
    Processor_cpu
};
 
bool protonect_shutdown = false; // Whether the running application should shut down.
 
void sigint_handler(int s)
{
    protonect_shutdown = true;
}
 
int main()
{

//定义变量
    std::cout << "start!" << std::endl;
    libfreenect2::Freenect2 freenect2;
    libfreenect2::Freenect2Device *dev = 0;
    libfreenect2::PacketPipeline  *pipeline = 0;



//搜寻并初始化传感器
    if(freenect2.enumerateDevices() == 0)
    {
        std::cout << "no device connected!" << std::endl;
        return -1;
    }
    string serial = freenect2.getDefaultDeviceSerialNumber();
    std::cout << "SERIAL: " << serial << std::endl;

//配置传输格式
#if 1 // sean
    int depthProcessor = Processor_cl;
    if(depthProcessor == Processor_cpu)
    {
        if(!pipeline)
            //! [pipeline]
            pipeline = new libfreenect2::CpuPacketPipeline();
        //! [pipeline]
    }
    else if (depthProcessor == Processor_gl) // if support gl
    {
#ifdef LIBFREENECT2_WITH_OPENGL_SUPPORT
        if(!pipeline)
        {
            pipeline = new libfreenect2::OpenGLPacketPipeline();
        }
#else
        std::cout << "OpenGL pipeline is not supported!" << std::endl;
#endif
    }
    else if (depthProcessor == Processor_cl) // if support cl
    {
#ifdef LIBFREENECT2_WITH_OPENCL_SUPPORT
        if(!pipeline)
            pipeline = new libfreenect2::OpenCLPacketPipeline();
#else
        std::cout << "OpenCL pipeline is not supported!" << std::endl;
#endif
    }



//启动设备
    if(pipeline)
    {
        dev = freenect2.openDevice(serial, pipeline);
    }
    else
    {
        dev = freenect2.openDevice(serial);
    }
    if(dev == 0)
    {
        std::cout << "failure opening device!" << std::endl;
        return -1;
    }
    signal(SIGINT, sigint_handler);
    protonect_shutdown = false;
    libfreenect2::SyncMultiFrameListener listener(
            libfreenect2::Frame::Color |
            libfreenect2::Frame::Depth |
            libfreenect2::Frame::Ir);
    libfreenect2::FrameMap frames;
    dev->setColorFrameListener(&listener);
    dev->setIrAndDepthFrameListener(&listener);
 

//启动数据传输
    dev->start();
 
    std::cout << "device serial: " << dev->getSerialNumber() << std::endl;
    std::cout << "device firmware: " << dev->getFirmwareVersion() << std::endl;
 



//循环接收
    libfreenect2::Registration* registration = new libfreenect2::Registration(dev->getIrCameraParams(), dev->getColorCameraParams());
    libfreenect2::Frame undistorted(512, 424, 4), registered(512, 424, 4), depth2rgb(1920, 1080 + 2, 4);

 
    Mat rgbmat, depthmat, rgbd, dst;
    float x, y, z, color;

    pcl::visualization::CloudViewer viewer ("Viewer");  //创建一个显示点云的窗口



    while(!protonect_shutdown)
    {
        listener.waitForNewFrame(frames);
        libfreenect2::Frame *rgb = frames[libfreenect2::Frame::Color];
        libfreenect2::Frame *depth = frames[libfreenect2::Frame::Depth];
        registration->apply(rgb, depth, &undistorted, &registered, true, &depth2rgb);

        PointCloud::Ptr cloud ( new PointCloud ); //使用智能指针，创建一个空点云。这种指针用完会自动释放。
        for (int m = 0;  m < 512 ; m++)
        {
            for (int n = 0 ; n < 424 ; n++)
            {
                PointT p;
                registration->getPointXYZRGB(&undistorted, &registered, n, m, x, y, z, color);
                const uint8_t *c = reinterpret_cast<uint8_t*>(&color);
                uint8_t b = c[0];
                uint8_t g = c[1];
                uint8_t r = c[2];
                if (z<1.2 && y<0.2)  //暂时先通过限定xyz来除去不需要的点，点云分割还在学习中。。。
                {
                    p.z = -z;
                    p.x = x;
                    p.y = -y;
                    p.b = b;
                    p.g = g;
                    p.r = r;
                }
                cloud->points.push_back( p );
            }
        }
        viewer.showCloud (cloud);
        int key = cv::waitKey(1);
        protonect_shutdown = protonect_shutdown || (key > 0 && ((key & 0xFF) == 27)); // shutdown on escape
        listener.release(frames);
    }

    dev->stop();
    dev->close();
 
    delete registration;
 
#endif
 
    std::cout << "stop!" << std::endl;
    return 0;
}

---

3，CMakeLists.txt

cmake_minimum_required(VERSION 2.8)

project( main )
set(CMAKE_PREFIX_PATH ${CMAKE_PREFIX_PATH} $ENV{HOME}/freenect2/lib/cmake/freenect2)
find_package( OpenCV REQUIRED )
FIND_PACKAGE( PkgConfig REQUIRED )
FIND_PACKAGE( freenect2 REQUIRED )
find_package(PCL 1.2 REQUIRED)


include_directories("/usr/include/libusb-1.0/")
include_directories(${OpenCV_INCLUDE_DIRS})

include_directories( ${freenect2_INCLUDE_DIRS} )

include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})
list(REMOVE_ITEM PCL_LIBRARIES "vtkproj4")

add_executable( main main.cpp )
target_link_libraries( main  ${freenect2_LIBRARIES} ${OpenCV_LIBS} ${PCL_LIBRARIES} )