点云库PCL学习笔记 -- 点云滤波Filtering -- 7. CropHull 任意多边形内部点云提取

1. CropHull 任意多边形内部点云提取代码

CropHull 任意多边形内部点云提取代码crophull.cpp

#include <pcl/visualization/cloud_viewer.h>
#include <iostream>
#include <pcl/io/io.h>
#include <pcl/io/pcd_io.h>
#include <vector>
#include <pcl/point_cloud.h>
#include <pcl/point_types.h>
#include <pcl/io/pcd_io.h>
#include <pcl/filters/crop_hull.h>
#include <pcl/surface/concave_hull.h>

int main(int argc, char** argv)
{
    //定义并实例化一个PointCloud指针对象，并用输入参数文件进行相关赋值
	pcl::PointCloud<pcl::PointXYZ>::Ptr cloud (new pcl::PointCloud<pcl::PointXYZ>);
	pcl::PCDReader reader;
	reader.read(argv[1],*cloud);	//输入滤波对象点云

	//输入 2D 平面点云
	pcl::PointCloud<pcl::PointXYZ>::Ptr boundingbox_ptr (new pcl::PointCloud<pcl::PointXYZ>);
	boundingbox_ptr->push_back(pcl::PointXYZ(0.1, 0.1, 0));
	boundingbox_ptr->push_back(pcl::PointXYZ(0.1, -0.1,0 ));
	boundingbox_ptr->push_back(pcl::PointXYZ(-0.1, 0.1,0 ));
	boundingbox_ptr->push_back(pcl::PointXYZ(-0.1, -0.1,0 ));
	boundingbox_ptr->push_back(pcl::PointXYZ(0.15, 0.1,0 ));

	pcl::ConvexHull<pcl::PointXYZ> hull;	//创建凸包对象
	hull.setInputCloud(boundingbox_ptr);	//设置输入点云
	hull.setDimension(2);					//设置凸包维度
	std::vector<pcl::Vertices> polygons;	//设置 pcl::Vertice 类型的向量，用于保存凸包顶点
	
	//该点云用于描述凸包形状
	pcl::PointCloud<pcl::PointXYZ>::Ptr surface_hull (new pcl::PointCloud<pcl::PointXYZ>);
	hull.reconstruct(*surface_hull, polygons);		//计算 2D 凸包结果

	pcl::PointCloud<pcl::PointXYZ>::Ptr objects (new pcl::PointCloud<pcl::PointXYZ>);
	pcl::CropHull<pcl::PointXYZ> bb_filter;		//创建 CropHull 对象
	bb_filter.setDim(2);						//设置维度
	bb_filter.setInputCloud(cloud);				//设置输入需要滤波的点云
	bb_filter.setHullIndices(polygons);			//输入封闭多边形的顶点
	bb_filter.setHullCloud(surface_hull);		//输入封闭多边形的形状
	bb_filter.filter(*objects);					//执行 CropHull 滤波，结果存储到 objects
	
	std::cout << objects->size() << std::endl;		//打印输出滤波后的点云数量信息

	//可视化视窗界面
	boost::shared_ptr<pcl::visualization::PCLVisualizer> for_visualizer_v (new pcl::visualization::PCLVisualizer ("crophull display"));
	for_visualizer_v->setBackgroundColor(255,255,255);

	//界面视窗1：用于显示输入的点云图像 cloud
	int v1(0);
	for_visualizer_v->createViewPort (0.0, 0.0, 0.33, 1, v1);
	for_visualizer_v->setBackgroundColor (255, 255, 255, v1);
	for_visualizer_v->addPointCloud (cloud,"cloud",v1);
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_COLOR,255,0,0,"cloud");
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE,3,"cloud");
	for_visualizer_v->addPolygon<pcl::PointXYZ>(surface_hull,0,.069*255,0.2*255,"backview_hull_polyline1",v1);

	//界面视窗2：用于封闭多边形的点云 surface_hull
	int v2(0);
	for_visualizer_v->createViewPort (0.33, 0.0, 0.66, 1, v2);	
	for_visualizer_v->setBackgroundColor (255, 255, 255, v2);
	for_visualizer_v->addPointCloud (surface_hull,"surface_hull",v2);
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_COLOR,255,0,0,"surface_hull");
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE,8,"surface_hull");
	for_visualizer_v->addPolygon<pcl::PointXYZ>(surface_hull,0,.069*255,0.2*255,"backview_hull_polyline",v2);

	//界面视窗3：用于经过滤波后的点云 objects
	int v3(0);
	for_visualizer_v->createViewPort (0.66, 0.0, 1, 1, v3);
	for_visualizer_v->setBackgroundColor (255, 255, 255, v3);
	for_visualizer_v->addPointCloud (objects,"objects",v3);
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_COLOR,255,0,0,"objects");
	for_visualizer_v->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE,3,"objects");

	while (!for_visualizer_v->wasStopped())
	{

		for_visualizer_v->spinOnce(1000);
	}
	system("pause");
}

2. 编译文件

设置编译文件CMakeLists.txt

cmake_minimum_required(VERSION 2.8 FATAL_ERROR)

project(crophull)
find_package(PCL 1.7 REQUIRED)
include_directories(${PCL_INCLUDE_DIRS})
link_directories(${PCL_LIBRARY_DIRS})
add_definitions(${PCL_DEFINITIONS})

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

mkdir build
cd build/
cmake ..
make

3. 测试

执行程序

cd ..
./build/crophull pig.pcd

结果如下：

使用pcl_viewer -fc 0,200,200 pig.pcd查看pig.pcd文件，如下
（-fc 0,200,200）是设置点云颜色的相关参数：颜色参数为（0,200,200）

• 开始执行程序后
  可以清楚的看到多边形对原始点云进行相关的点云信息的提取。