PCL实现选框裁剪点云
Posted Leslie X徐
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PCL实现选框裁剪点云
需求：在屏幕上点击画出多边形，裁剪对应框内的点云。
实现：按"x" 绘制多边形 再按"x"裁剪
实现算法来自 PCL裁剪之多边形裁剪
一、实现屏幕画线
1.实现屏幕坐标转换至世界坐标
/**
* @brief getScreentPos 屏幕坐标转换至世界坐标
* @param displayPos 输入：屏幕坐标
* @param world 输出：世界坐标
* @param viewer_void 输入：pclViewer
*/
void getScreentPos(double* displayPos, double* world,void* viewer_void)
pcl::visualization::PCLVisualizer* viewer = static_cast<pcl::visualization::PCLVisualizer*> (viewer_void);
vtkRenderer* rendererviewer->getRendererCollection()->GetFirstRenderer();
// First compute the equivalent of this display point on the focal plane
double fp[4], tmp1[4], eventFPpos[4];
renderer->GetActiveCamera()->GetFocalPoint(fp);
fp[3] = 0.0;
renderer->SetWorldPoint(fp);
renderer->WorldToDisplay();
renderer->GetDisplayPoint(tmp1);
tmp1[0] = displayPos[0];
tmp1[1] = displayPos[1];
renderer->SetDisplayPoint(tmp1);
renderer->DisplayToWorld();
renderer->GetWorldPoint(eventFPpos);
// Copy the result
for (int i=0; i<3; i++)
world[i] = eventFPpos[i];
2.绑定鼠标
void mouseEventOccurred(const pcl::visualization::MouseEvent& event,void* viewer_void)
pcl::visualization::PCLVisualizer* viewer = static_cast<pcl::visualization::PCLVisualizer*> (viewer_void);
if (event.getButton() == pcl::visualization::MouseEvent::LeftButton &&
event.getType() == pcl::visualization::MouseEvent::MouseButtonRelease)
std::cout << "Left mouse button released at position (" << event.getX() << ", " << event.getY() << ")" << std::endl;
if(isPickingMode)
double world_point[3];
double displayPos[2];
displayPos[0]=double(event.getX()),displayPos[1]=double(event.getY());
getScreentPos(displayPos, world_point,viewer_void);
std::cout<<endl<<world_point[0]<<','<<world_point[1]<<','<<world_point[2]<<endl;
curP=pcl::PointXYZ(world_point[0], world_point[1], world_point[2]);
if(!flag)flag=true;
else
char str1[512];
sprintf(str1, "line#%03d", line_id++);//名字不能重复
viewer->addLine(lastP,curP,str1);
lastP=curP;
//切割点云添加
cloud_polygon->push_back(curP);
二、实现裁剪算法
1.计算某点与多边形的边的关系，判断是否在内
/**
* @brief inOrNot1
* @param poly_sides 平面上绘制多边形的顶点数
* @param poly_X 顶点的x坐标数组
* @param poly_Y 顶点的y坐标数组
* @param x 目标点云的x坐标
* @param y 目标点云的y坐标
* @return
*/
int inOrNot1(int poly_sides, double *poly_X, double *poly_Y, double x, double y)
int i, j;
j = poly_sides - 1;
int res = 0;
//对每一条边进行遍历，该边的两个端点，有一个必须在待检测点(x,y)的左边，且两个点中，有一个点的y左边比p.y小，另一个点的y比p.y大。
for (i = 0; i < poly_sides; i++)
if (( (poly_Y[i] < y && poly_Y[j] >= y) || (poly_Y[j] < y && poly_Y[i] >= y) ) && (poly_X[i] <= x || poly_X[j] <= x))
//用水平的直线与该边相交，求交点的x坐标。
res ^= ((poly_X[i] + (y - poly_Y[i]) / (poly_Y[j] - poly_Y[i]) *(poly_X[j] - poly_X[i])) < x);
j = i;
return res;
2.实现裁剪
思路：将点云和多边形投影在一个平面上过滤出在多边形内的点的索引
void projectInliers(void* viewer_void)
pcl::visualization::PCLVisualizer* viewer = static_cast<pcl::visualization::PCLVisualizer*> (viewer_void);
//获取相机焦点和位置信息
double focal[3]=0; double pos[3] = 0;
vtkRenderer* rendererviewer->getRendererCollection()->GetFirstRenderer();
renderer->GetActiveCamera()->GetFocalPoint(focal);
renderer->GetActiveCamera()->GetPosition(pos);
std::cout<<"focal: "<<focal[0]<<','<<focal[1]<<','<<focal[2]<<endl;
std::cout<<"pos: "<<pos[0]<<','<<pos[1]<<','<<pos[2]<<endl;
//获取焦点单位向量
pcl::PointXYZ eyeLine1 = pcl::PointXYZ(focal[0] - pos[0], focal[1] - pos[1], focal[2] - pos[2]);
float mochang = sqrt(pow(eyeLine1.x, 2) + pow(eyeLine1.y, 2) + pow(eyeLine1.z, 2));//模长
pcl::PointXYZ eyeLine = pcl::PointXYZ(eyeLine1.x / mochang, eyeLine1.y / mochang, eyeLine1.z / mochang);//单位向量 法向量
//根据法向量创建一个平面
pcl::ModelCoefficients::Ptr coefficients(new pcl::ModelCoefficients());//ax+by+cz+d=0
coefficients->values.resize(4);
coefficients->values[0] = eyeLine.x;
coefficients->values[1] = eyeLine.y;
coefficients->values[2] = eyeLine.z;
coefficients->values[3] = 0;
//创建保存结果投影的点云
pcl::PointCloud<pcl::PointXYZ>::Ptr cloudIn_Prj(new pcl::PointCloud<pcl::PointXYZ>);//过滤输入的点云
pcl::PointCloud<pcl::PointXYZ>::Ptr cloudCiecle_result(new pcl::PointCloud<pcl::PointXYZ>);//过滤绘制的多边形的点云
// 创建滤波器对象
pcl::ProjectInliers<pcl::PointXYZ> proj;//建立投影对象
proj.setModelType(pcl::SACMODEL_PLANE);//设置投影类型
proj.setInputCloud(cloud_polygon);//设置输入点云
proj.setModelCoefficients(coefficients);//加载投影参数
proj.filter(*cloudCiecle_result);//执行程序，并将结果保存
// 创建滤波器对象
pcl::ProjectInliers<pcl::PointXYZ> projCloudIn;//建立投影对象
projCloudIn.setModelType(pcl::SACMODEL_PLANE);//设置投影类型
projCloudIn.setInputCloud(cloud_in);//设置输入点云
projCloudIn.setModelCoefficients(coefficients);//加载投影参数
projCloudIn.filter(*cloudIn_Prj);//执行程序，并将结果保存
int ret=-1;
double *PloyXarr = new double[cloudCiecle_result->points.size()];
double *PloyYarr = new double[cloudCiecle_result->points.size()];
for (int i = 0; i < cloudCiecle_result->points.size(); i++)
PloyXarr[i] = cloudCiecle_result->points[i].x;
PloyYarr[i] = cloudCiecle_result->points[i].y;
cloud_cliped->clear();
for (int i = 0; i < cloudIn_Prj->points.size(); i++)
//判断
ret = inOrNot1(cloud_polygon->points.size(), PloyXarr, PloyYarr, cloudIn_Prj->points[i].x, cloudIn_Prj->points[i].y);
if (1 == ret)//表示在里面
cloud_cliped->points.push_back(cloud_in->points[i]);
//表示在外面
viewer->removeAllPointClouds();
viewer->addPointCloud(cloud_cliped,"aftercut");
cloud_in->clear();
pcl::copyPointCloud(*cloud_cliped,*cloud_in);
viewer->getRenderWindow()->Render();
三、绑定鼠标键盘事件
1.静态函数回调
boost::shared_ptr<pcl::visualization::PCLVisualizer> interactionCustomizationVis()
boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer("3D Viewer"));
viewer->setBackgroundColor(0, 0, 0);
viewer->addCoordinateSystem(1.0);
viewer->setWindowName("鼠标键盘事件");
viewer->addPointCloud(cloud_polygon,"polyline");
viewer->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_COLOR,1,0,0,"polyline");
viewer->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE,8,"polyline");
viewer->registerKeyboardCallback(keyboardEventOccurred, (void*)viewer.get());
viewer->registerMouseCallback(mouseEventOccurred, (void*)viewer.get());
return (viewer);
2.当回调函数为类成员
//绑定鼠标键盘事件
std::function<void(const pcl::visualization::KeyboardEvent&)> keyfun =
std::bind(&PointCloudDlg::keyboardEventOccurred, this, std::placeholders::_1);//std::placeholders 占位符 _1为第一个参数
std::function<void(const pcl::visualization::MouseEvent&)> mousefun =
std::bind(&PointCloudDlg::mouseEventOccurred, this, std::placeholders::_1);
viewer->registerKeyboardCallback(keyfun);
viewer->registerMouseCallback(mousefun);
四、加载和保存
1.加载
void load()
boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer);
pcl::PCDReader reader;
reader.read("in.pcd",*cloud_in);
viewer->addPointCloud(cloud_in,"cloud_in");
2.保存
注意：如果保存发生错误，可能是无法确认点云大小引起，需要设置height和width
void save()
//对于无序点云hight默认是1
cloud_cliped->height = 1;
//点云文件中push_back了j个点，故width=j
cloud_cliped->width = cloud_cliped->points.size();
pcl::io::savePCDFileASCII("out.pcd",*cloud_cliped);
五、源代码
#include <iostream>
#include <boost/thread/thread.hpp>
#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/visualization/mouse_event.h> //鼠标事件
#include <pcl/visualization/keyboard_event.h>//键盘事件
#include <pcl/filters/project_inliers.h>
#include <pcl/ModelCoefficients.h>
#include "vtkCamera.h"
#include <vtkRenderWindow.h>
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_in (new pcl::PointCloud<pcl::PointXYZ>);
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_polygon (new pcl::PointCloud<pcl::PointXYZ>);
pcl::PointCloud<pcl::PointXYZ>::Ptr cloud_cliped (new pcl::PointCloud<pcl::PointXYZ>);
pcl::PointXYZ curP,lastP;
bool flag=false;//判断是不是第一次点击
bool isPickingMode = false;
unsigned int line_id = 0;
boost::shared_ptr<pcl::visualization::PCLVisualizer> interactionCustomizationVis();
void getScreentPos(double* displayPos, double* world,void* viewer_void);
void keyboardEventOccurred(const pcl::visualization::KeyboardEvent& event,void* viewer_void);
void mouseEventOccurred(const pcl::visualization::MouseEvent& event,void* viewer_void);
int inOrNot1(int poly_sides, double *poly_X, double *poly_Y, double x, double y);
void projectInliers(void*);
int main(int argc, char** argv)
boost::shared_ptr<pcl::visualization::PCLVisualizer> viewerPCL实现选框裁剪点云