点云可视化-点击显示点坐标

Posted 2023-04-30

参考技术A 1、点云可视化

基于点云库PCL1.8.1

1.1包含头文件

#include

#include

#include

#include

using namespace pcl;

typedef pcl:: PointXYZ PointT ;

typedef pcl:: PointCloud PointCloudT ;

// Mutex: //进程锁

boost:: mutex cloud_mutex;

//用于给回调函数的结构体定义

struct callback_args



PointCloudT :: Ptr clicked_points_3d;

pcl::visualization:: PCLVisualizer :: Ptr viewerPtr;

;

//回调函数

//按住shift，鼠标右键点一下点云，会显示出点的距离

void pp_callback( const pcl::visualization:: PointPickingEvent & event , void * args )



struct callback_args * data = ( struct callback_args *) args ;

if ( event .getPointIndex() == -1)

return ;

PointT current_point;

event .getPoint(current_point.x, current_point.y, current_point.z);

//TODO

data->clicked_points_3d -> clear(); //将上次选的点清空

data->clicked_points_3d -> points.push_back(current_point); //添加新选择的点

// Draw clicked points in red:将选中点用红色标记

pcl::visualization:: PointCloudColorHandlerCustom red(data->clicked_points_3d, 255, 0, 0);

data->viewerPtr -> removePointCloud( "clicked_points" );

data->viewerPtr -> addPointCloud(data->clicked_points_3d, red, "clicked_points" );

data->viewerPtr -> setPointCloudRenderingProperties(pcl::visualization:: PCL_VISUALIZER_POINT_SIZE , 10, "clicked_points" );

std::cout

PCL实现选框裁剪点云

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)

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