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图像处理，大家都知道它有显著的优点和缺点。优点就是分辨率高，信息丰富。缺点就是，整个图像本身没有深度信息。过去在深度信息这部分，大家一般都倚重于激光雷达，但是激光雷达价格比较高，所以一般用的比较少。但是，现在随着3d camera、多线激光雷达的普及，特别是价格的大幅度下降，这样的话，我们不仅可以使用图像来作为数据输入的来源，还可以使用多线雷达的点云，这一点相比较以前就很方便了。
1、pcl点云库的安装
在树莓派4b上面安装点云库，还是很方便的，直接用sudo安装即可，
sudo apt-get install libpcl-dev2、准备CMakeLists.txt
为了验证pcl点云库是不是真的安装好了，我们有必要编写一个程序验证一下。在这之前，先准备一个cmake的编译脚本CMakeLists.txt，
cmake_minimum_required(VERSION 3.5 FATAL_ERROR)
project(pcd_write)
find_package(PCL 1.2 REQUIRED)
include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})
add_executable (pcd_write pcd_write.cpp)
target_link_libraries (pcd_write ${PCL_LIBRARIES})
3、准备pcd_write.cpp
准备好了编译脚本之后，接下来就是源代码文件，这部分可以复用我们之前写过的一个代码，命名为pcd_write.cpp。
#include <iostream>
#include <pcl/io/pcd_io.h>
#include <pcl/point_types.h>
int
main ()
{
pcl::PointCloud<pcl::PointXYZ> cloud;
// Fill in the cloud data
cloud.width = 5;
cloud.height = 1;
cloud.is_dense = false;
cloud.resize (cloud.width * cloud.height);
for (auto& point: cloud)
{
point.x = 1024 * rand () / (RAND_MAX + 1.0f);
point.y = 1024 * rand () / (RAND_MAX + 1.0f);
point.z = 1024 * rand () / (RAND_MAX + 1.0f);
}
pcl::io::savePCDFileASCII ("test_pcd.pcd", cloud);
std::cerr << "Saved " << cloud.size () << " data points to test_pcd.pcd." << std::endl;
for (const auto& point: cloud)
std::cerr << " " << point.x << " " << point.y << " " << point.z << std::endl;
return (0);
}
4、生成makefile并编译
有了CMakeLists.txt和cpp文件，下面就可以开始编译了。编译的方法有两步，即cmake . && make。如果在这过程中没有出现错误的话，就代表我们的编译时ok的。
5、执行
编译好了，只是第一步，第二步还需要跑起来看一下。如果跑起来也没问题，才能说明pcl安装是正确的。
feixiaoxing@raspberrypi:~/Desktop/pcl $ ./pcd_write
Saved 5 data points to test_pcd.pcd.
0.352222 -0.151883 -0.106395
-0.397406 -0.473106 0.292602
-0.731898 0.667105 0.441304
-0.734766 0.854581 -0.0361733
-0.4607 -0.277468 -0.916762
有兴趣的同学可以通过ldd看看pcd_write依赖于哪些动态库，这也是蛮有意思的，
feixiaoxing@raspberrypi:~/Desktop/pcl $ ldd pcd_write
linux-vdso.so.1 (0x0000007f8ea8f000)
libpcl_io.so.1.13 => /lib/aarch64-linux-gnu/libpcl_io.so.1.13 (0x0000007f8e760000)
libpcl_common.so.1.13 => /lib/aarch64-linux-gnu/libpcl_common.so.1.13 (0x0000007f8e690000)
libstdc++.so.6 => /lib/aarch64-linux-gnu/libstdc++.so.6 (0x0000007f8e470000)
libgcc_s.so.1 => /lib/aarch64-linux-gnu/libgcc_s.so.1 (0x0000007f8e430000)
libc.so.6 => /lib/aarch64-linux-gnu/libc.so.6 (0x0000007f8e280000)
libboost_filesystem.so.1.74.0 => /lib/aarch64-linux-gnu/libboost_filesystem.so.1.74.0 (0x0000007f8e240000)
libboost_iostreams.so.1.74.0 => /lib/aarch64-linux-gnu/libboost_iostreams.so.1.74.0 (0x0000007f8e200000)
libpcl_io_ply.so.1.13 => /lib/aarch64-linux-gnu/libpcl_io_ply.so.1.13 (0x0000007f8e190000)
libvtkIOGeometry-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkIOGeometry-9.1.so.1 (0x0000007f8e010000)
libvtkIOPLY-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkIOPLY-9.1.so.1 (0x0000007f8dfd0000)
libpng16.so.16 => /lib/aarch64-linux-gnu/libpng16.so.16 (0x0000007f8df70000)
libusb-1.0.so.0 => /lib/aarch64-linux-gnu/libusb-1.0.so.0 (0x0000007f8df40000)
libOpenNI2.so.0 => /lib/aarch64-linux-gnu/libOpenNI2.so.0 (0x0000007f8dec0000)
libOpenNI.so.0 => /lib/libOpenNI.so.0 (0x0000007f8de20000)
libpcap.so.0.8 => /lib/aarch64-linux-gnu/libpcap.so.0.8 (0x0000007f8ddb0000)
libgomp.so.1 => /lib/aarch64-linux-gnu/libgomp.so.1 (0x0000007f8dd40000)
libm.so.6 => /lib/aarch64-linux-gnu/libm.so.6 (0x0000007f8dca0000)
libvtkIOImage-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkIOImage-9.1.so.1 (0x0000007f8db30000)
libvtkIOLegacy-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkIOLegacy-9.1.so.1 (0x0000007f8da80000)
libvtkImagingCore-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkImagingCore-9.1.so.1 (0x0000007f8d8c0000)
libvtkIOCore-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkIOCore-9.1.so.1 (0x0000007f8d840000)
libvtkCommonExecutionModel-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonExecutionModel-9.1.so.1 (0x0000007f8d700000)
libvtkCommonDataModel-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonDataModel-9.1.so.1 (0x0000007f8d290000)
libvtkCommonCore-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonCore-9.1.so.1 (0x0000007f8c940000)
/lib/ld-linux-aarch64.so.1 (0x0000007f8ea52000)
libz.so.1 => /lib/aarch64-linux-gnu/libz.so.1 (0x0000007f8c900000)
libbz2.so.1.0 => /lib/aarch64-linux-gnu/libbz2.so.1.0 (0x0000007f8c8d0000)
liblzma.so.5 => /lib/aarch64-linux-gnu/liblzma.so.5 (0x0000007f8c880000)
libzstd.so.1 => /lib/aarch64-linux-gnu/libzstd.so.1 (0x0000007f8c7c0000)
libvtkFiltersHybrid-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkFiltersHybrid-9.1.so.1 (0x0000007f8c6e0000)
libvtkRenderingCore-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkRenderingCore-9.1.so.1 (0x0000007f8c4e0000)
libjsoncpp.so.25 => /lib/aarch64-linux-gnu/libjsoncpp.so.25 (0x0000007f8c490000)
libvtkFiltersGeneral-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkFiltersGeneral-9.1.so.1 (0x0000007f8c090000)
libvtkFiltersCore-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkFiltersCore-9.1.so.1 (0x0000007f8b990000)
libvtkCommonSystem-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonSystem-9.1.so.1 (0x0000007f8b930000)
libvtkCommonTransforms-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonTransforms-9.1.so.1 (0x0000007f8b8d0000)
libvtkCommonMath-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonMath-9.1.so.1 (0x0000007f8b890000)
libvtksys-9.1.so.1 => /lib/aarch64-linux-gnu/libvtksys-9.1.so.1 (0x0000007f8b820000)
libvtkCommonMisc-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonMisc-9.1.so.1 (0x0000007f8b440000)
libudev.so.1 => /lib/aarch64-linux-gnu/libudev.so.1 (0x0000007f8b3f0000)
libpthread.so.0 => /lib/aarch64-linux-gnu/libpthread.so.0 (0x0000007f8b3c0000)
libjpeg.so.62 => /lib/aarch64-linux-gnu/libjpeg.so.62 (0x0000007f8b340000)
libtinyxml.so.2.6.2 => /lib/aarch64-linux-gnu/libtinyxml.so.2.6.2 (0x0000007f8b300000)
libdbus-1.so.3 => /lib/aarch64-linux-gnu/libdbus-1.so.3 (0x0000007f8b280000)
libvtkDICOMParser-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkDICOMParser-9.1.so.1 (0x0000007f8b240000)
libvtkmetaio-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkmetaio-9.1.so.1 (0x0000007f8b190000)
libvtkpugixml-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkpugixml-9.1.so.1 (0x0000007f8b130000)
libtiff.so.6 => /lib/aarch64-linux-gnu/libtiff.so.6 (0x0000007f8b090000)
libtbb.so.12 => /lib/aarch64-linux-gnu/libtbb.so.12 (0x0000007f8b030000)
libdouble-conversion.so.3 => /lib/aarch64-linux-gnu/libdouble-conversion.so.3 (0x0000007f8aff0000)
liblz4.so.1 => /lib/aarch64-linux-gnu/liblz4.so.1 (0x0000007f8afa0000)
libvtkloguru-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkloguru-9.1.so.1 (0x0000007f8af50000)
libvtkImagingSources-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkImagingSources-9.1.so.1 (0x0000007f8af00000)
libvtkFiltersGeometry-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkFiltersGeometry-9.1.so.1 (0x0000007f8ae20000)
libvtkCommonColor-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonColor-9.1.so.1 (0x0000007f8ade0000)
libvtkFiltersSources-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkFiltersSources-9.1.so.1 (0x0000007f8ad20000)
libvtkCommonComputationalGeometry-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkCommonComputationalGeometry-9.1.so.1 (0x0000007f8acd0000)
libvtkfmt-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkfmt-9.1.so.1 (0x0000007f8ac90000)
libvtkkissfft-9.1.so.1 => /lib/aarch64-linux-gnu/libvtkkissfft-9.1.so.1 (0x0000007f8ac60000)
libsystemd.so.0 => /lib/aarch64-linux-gnu/libsystemd.so.0 (0x0000007f8ab70000)
libwebp.so.7 => /lib/aarch64-linux-gnu/libwebp.so.7 (0x0000007f8aaf0000)
libLerc.so.4 => /lib/aarch64-linux-gnu/libLerc.so.4 (0x0000007f8aa40000)
libjbig.so.0 => /lib/aarch64-linux-gnu/libjbig.so.0 (0x0000007f8aa10000)
libdeflate.so.0 => /lib/aarch64-linux-gnu/libdeflate.so.0 (0x0000007f8a9d0000)
libcap.so.2 => /lib/aarch64-linux-gnu/libcap.so.2 (0x0000007f8a9a0000)
libgcrypt.so.20 => /lib/aarch64-linux-gnu/libgcrypt.so.20 (0x0000007f8a890000)
libgpg-error.so.0 => /lib/aarch64-linux-gnu/libgpg-error.so.0 (0x0000007f8a840000)