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PCL: RGB-D图像转换成点云数据+点云融合

2020-05-18  本文已影响0人  AI秘籍

1. 题目

已经给定3帧(不连续)RGB-D相机拍摄的 RGB + depth 图像,以及他们之间的变换矩阵(以第一帧为参考帧),请将上述3帧RGB-D图像分别生成点云并融合出最终的点云输出。
数据如下:


rgb0.png
rgb1.png
rgb2.png
depth0.png
depth1.png
depth2.png

相机位姿文件:
cameraTrajectory.txt内容如下:
//# tx ty tz qx qy qz qw
0.000000000 0.000000000 0.000000000 0.000000000 0.000000000 0.000000000 1.000000000
-0.288952827 0.222811699 -0.252029210 0.054562528 -0.312418818 -0.288284063 0.903498590
-0.650643229 0.383824050 -0.501303971 -0.016285975 -0.159155473 -0.111743204 0.980774045


image.png

2.RGBD图像转点云数据+点云融合代码

// RDGD图像转点云数据
#include <pcl/point_types.h>
//点云文件IO(pcd文件和ply文件)
#include <pcl/io/pcd_io.h>
#include <pcl/io/ply_io.h>
//kd树
#include <pcl/kdtree/kdtree_flann.h>
//特征提取
#include <pcl/features/normal_3d_omp.h>
#include <pcl/features/normal_3d.h>
//重构
#include <pcl/surface/gp3.h>
#include <pcl/surface/poisson.h>
//可视化
#include <pcl/visualization/pcl_visualizer.h>
// 矩阵变换
#include <pcl/common/transforms.h>
//多线程
#include <boost/thread/thread.hpp>
#include <fstream>
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <string>
#include <opencv2/opencv.hpp>
#include <eigen3/Eigen/Dense>

using namespace std;
using namespace cv;

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

// camera instrinsic parameters相机内参
struct CAMERA_INTRINSIC_PARAMETERS
{
    double fx, fy, cx, cy, scale;
};

// RGBD图像转点云数据
PointCloud::Ptr image2PointCloud(
        Mat rgb,
        Mat depth,
        CAMERA_INTRINSIC_PARAMETERS camera)
{
    PointCloud::Ptr cloud(new PointCloud);
    for (int m = 0; m < depth.rows; m++)
        for (int n = 0; n < depth.cols; n++)
        {
            // 获取深度图中(m,n)处的值
            ushort d = depth.ptr<ushort>(m)[n];
            // d 可能没有值,若如此,跳过此点
            if (d == 0)
                continue;
            // d 存在值,则向点云增加一个点
            PointT p;
            // 计算这个点的空间坐标
            p.z = double(d) / camera.scale;
            p.x = (n - camera.cx) * p.z / camera.fx;
            p.y = (m - camera.cy) * p.z / camera.fy;

            // 从rgb图像中获取它的颜色
            p.b = rgb.ptr<uchar>(m)[n * 3];
            p.g = rgb.ptr<uchar>(m)[n * 3 + 1];
            p.r = rgb.ptr<uchar>(m)[n * 3 + 2];

            // 把p加入到点云中
            cloud->points.push_back(p);
        }
    // 设置并保存点云
    cloud->height = 1;
    cloud->width = cloud->points.size();
    cloud->is_dense = false;
    return cloud;
}

// 读取相机姿态CameraTrajectory
// # tx ty tz qx qy qz qw
void readCameraTrajectory(
        string camTransFile,
        vector<Eigen::Isometry3d> &poses)
{
    ifstream fcamTrans(camTransFile);
    if (!fcamTrans.is_open())
    {
        cerr << "trajectory is empty!" << endl;
        return;
    }
    else
    {
        string str;
        while ((getline(fcamTrans, str)))
        {
            Eigen::Quaterniond q; //四元数
            Eigen::Vector3d t;
            Eigen::Isometry3d T = Eigen::Isometry3d::Identity();
            // 第一行为注释
            if (str.at(0) == '#')
            {
                cout << "str" << str << endl;
                continue;
            }
            istringstream strdata(str);

            strdata >> t[0] >> t[1] >> t[2] >> q.x() >> q.y() >> q.z() >> q.w();
            T.rotate(q);
            T.pretranslate(t);
            poses.push_back(T);
        }
    }
}

// 简单点云叠加融合
PointCloud::Ptr pointCloudFusion( 
    PointCloud::Ptr &original, 
    cv::Mat curr_rgb_im,
    cv::Mat curr_depth_im, 
    Eigen::Isometry3d T, 
    CAMERA_INTRINSIC_PARAMETERS camera )
{
    // ---------- 开始你的代码  ------------- -//
    PointCloud::Ptr newCloud(new PointCloud()),transCloud(new PointCloud());
    newCloud=image2PointCloud(curr_rgb_im,curr_depth_im,camera);
    pcl::transformPointCloud(*newCloud,*transCloud,T.matrix());
    *original+=*transCloud;
    return original;
    // ---------- 结束你的代码  ------------- -//
}

// 显示rgb点云
boost::shared_ptr<pcl::visualization::PCLVisualizer> rgbVis(
    pcl::PointCloud<pcl::PointXYZRGB>::ConstPtr cloud)
{
  // --------------------------------------------
  // -----Open 3D viewer and add point cloud-----
  // --------------------------------------------
  boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer(new pcl::visualization::PCLVisualizer("3D Viewer"));
  viewer->setBackgroundColor(0, 0, 0);
  pcl::visualization::PointCloudColorHandlerRGBField<pcl::PointXYZRGB> rgb(cloud);
  viewer->addPointCloud<pcl::PointXYZRGB>(cloud, rgb, "sample cloud");
  viewer->setPointCloudRenderingProperties(pcl::visualization::PCL_VISUALIZER_POINT_SIZE, 3, "sample cloud");
  viewer->addCoordinateSystem(1.0);
  viewer->initCameraParameters();
  return (viewer);
}

int main()
{
    // 相机内参
    CAMERA_INTRINSIC_PARAMETERS cameraParams{517.0, 516.0, 318.6, 255.3, 5000.0};

    int frameNum = 3;
    vector<Eigen::Isometry3d> poses;
    PointCloud::Ptr fusedCloud(new PointCloud());
    string color_im_path = "xxx/rgb/rgb";
    string depth_im_path = "xxx/depth/depth";
    string cameraPosePath = "xxx/cameraTrajectory.txt";
    readCameraTrajectory(cameraPosePath, poses);
    for (int idx = 0; idx < frameNum; idx++)
    {
        string rgbPath = color_im_path + to_string(idx) + ".png";
        string depthPath = depth_im_path + to_string(idx) + ".png";
        cv::Mat color_im = cv::imread(rgbPath);
        if (color_im.empty())
        {
            cerr << "Fail to load rgb image!" << endl;
        }
        cv::Mat depth_im = cv::imread(depthPath, -1);
        if (depth_im.empty())
        {
            cerr << "Fail to load depth image!" << endl;
        }

        if (idx == 0)
        {
            fusedCloud = image2PointCloud(color_im, depth_im, cameraParams);
            boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer1;
            viewer1 = rgbVis(fusedCloud);
        }
        else
        {
            fusedCloud = pointCloudFusion(fusedCloud, color_im,depth_im, poses[idx], cameraParams);
        }
    }

    boost::shared_ptr<pcl::visualization::PCLVisualizer> viewer;
    viewer = rgbVis(fusedCloud);
    while (!viewer->wasStopped())
  {
    viewer->spinOnce(100);
    boost::this_thread::sleep(boost::posix_time::microseconds(100000));
  }
    pcl::io::savePCDFile( "fusedCloud.pcd", *fusedCloud );
    return 0;
}

第一帧点云


image.png

3帧点云融合


image.png

参考:

  1. https://mp.weixin.qq.com/s?__biz=MzIxOTczOTM4NA==&mid=2247486281&idx=1&sn=1b36bcfd9f492dabc44ae2f10562e040&chksm=97d7eedea0a067c89eb9b1e71f7cf5dd12410c8c81d43dc2a21f9c6f28babd7add017ad14705&scene=21#wechat_redirect
  2. https://blog.csdn.net/weixin_42905141/article/details/100765920
  3. 公众号:计算机视觉life
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