ORBSLAM输出的轨迹文件与TUM数据集真实轨迹进行空间对齐C++代码

以下是一个简单的C++代码片段，用于将ORBSLAM输出的轨迹文件与TUM数据集真实轨迹进行空间对齐：

#include <iostream>
#include <fstream>
#include <string>
#include <Eigen/Core>

using namespace std;
using namespace Eigen;

int main(int argc, char **argv) {
    if(argc != 4) {
        cerr << "Usage: align_traj <orbslam_traj> <tum_traj> <output_traj>" << endl;
        return 1;
    }

    // Load ORBSLAM trajectory file
    ifstream orbslam_file(argv[1]);
    if(!orbslam_file) {
        cerr << "Error: unable to open ORBSLAM trajectory file" << endl;
        return 1;
    }
    vector<Vector3d> orbslam_traj;
    while(!orbslam_file.eof()) {
        double timestamp, tx, ty, tz;
        orbslam_file >> timestamp >> tx >> ty >> tz;
        if(orbslam_file.fail()) break;
        orbslam_traj.push_back(Vector3d(tx, ty, tz));
    }
    orbslam_file.close();

    // Load TUM trajectory file
    ifstream tum_file(argv[2]);
    if(!tum_file) {
        cerr << "Error: unable to open TUM trajectory file" << endl;
        return 1;
    }
    vector<Vector3d> tum_traj;
    while(!tum_file.eof()) {
        double timestamp, tx, ty, tz, qx, qy, qz, qw;
        tum_file >> timestamp >> tx >> ty >> tz >> qx >> qy >> qz >> qw;
        if(tum_file.fail()) break;
        tum_traj.push_back(Vector3d(tx, ty, tz));
    }
    tum_file.close();

    // Compute transformation between ORBSLAM and TUM trajectories
    assert(orbslam_traj.size() == tum_traj.size());
    int num_poses = orbslam_traj.size();
    MatrixXd A(num_poses * 3, 6);
    VectorXd b(num_poses * 3);
    for(int i = 0; i < num_poses; i++) {
        Vector3d p1 = orbslam_traj[i];
        Vector3d p2 = tum_traj[i];
        A.block<3, 3>(i*3, 0) = Matrix3d::Identity();
        A.block<3, 3>(i*3, 3) = skew(p2);
        b.segment<3>(i*3) = p1 - p2;
    }
    VectorXd x = (A.transpose() * A).ldlt().solve(A.transpose() * b);
    Matrix4d T = Matrix4d::Identity();
    T.block<3, 3>(0, 0) = AngleAxisd(x[3], Vector3d::UnitX())
                          * AngleAxisd(x[4], Vector3d::UnitY())
                          * AngleAxisd(x[5], Vector3d::UnitZ()).toRotationMatrix();
    T.block<3, 1>(0, 3) = x.head<3>();

    // Transform ORBSLAM trajectory using computed transformation
    vector<Vector3d> aligned_traj;
    for(int i = 0; i < num_poses; i++) {
        Vector4d p(orbslam_traj[i].x(), orbslam_traj[i].y(), orbslam_traj[i].z(), 1);
        Vector4d p_aligned = T * p;
        aligned_traj.push_back(Vector3d(p_aligned.x(), p_aligned.y(), p_aligned.z()));
    }

    // Write aligned trajectory to output file
    ofstream output_file(argv[3]);
    if(!output_file) {
        cerr << "Error: unable to open output file" << endl;
        return 1;
    }
    for(int i = 0; i < num_poses; i++) {
        output_file << fixed << setprecision(6) << (i+1)*0.1;
        output_file << " " << aligned_traj[i].x();
        output_file << " " << aligned_traj[i].y();
        output_file << " " << aligned_traj[i].z() << endl;
    }
    output_file.close();

    return 0;
}

这段代码假定ORBSLAM输出的轨迹文件和TUM数据集真实轨迹文件都是简单的文本文件，每个位姿都包含时间戳和位姿矩阵（在ORBSLAM轨迹文件中，位姿矩阵只包含平移部分）。代码读取这两个文件，然后使用最小二乘法计算一个从ORBSLAM轨迹到TUM轨迹的刚性变换，最后将ORBSLAM轨迹变换到TUM轨迹的坐标系中，并将结果写入输出文件。