ORB-slam2代码分析3

    bool System::MapChanged()//检查地图变化
    {
    static int n=0;
    int curn = mpMap->GetLastBigChangeIdx();
    if(n<curn)
    {
        n=curn;
        return true;
    }
    else
        return false;
    }
    
    void System::Reset()//系统重置
    {
    unique_lock<mutex> lock(mMutexReset);
    mbReset = true;
    }
    
    void System::Shutdown()//关闭系统
    {
    mpLocalMapper->RequestFinish();//关闭地图
    mpLoopCloser->RequestFinish();//关闭回环
    if(mpViewer)//关闭观测
    {
        mpViewer->RequestFinish();
        while(!mpViewer->isFinished())
            usleep(5000);
    }
    
    // Wait until all thread have effectively stopped
    while(!mpLocalMapper->isFinished() || !mpLoopCloser->isFinished() || mpLoopCloser->isRunningGBA())
    {
        usleep(5000);
    }
    
    if(mpViewer)
        pangolin::BindToContext("ORB-SLAM2: Map Viewer");
    }

    void System::SaveTrajectoryTUM(const string &filename)//保存轨迹
    {
    cout << endl << "Saving camera trajectory to " << filename << " ..." << endl;
    if(mSensor==MONOCULAR)
    {
        cerr << "ERROR: SaveTrajectoryTUM cannot be used for monocular." << endl;
        return;
    }
    
    vector<KeyFrame*> vpKFs = mpMap->GetAllKeyFrames();
    sort(vpKFs.begin(),vpKFs.end(),KeyFrame::lId);//给关键帧排序
    
    // Transform all keyframes so that the first keyframe is at the origin.
    //转换所有关键帧以至于这个第一帧处于起始位置
    // After a loop closure the first keyframe might not be at the origin.
    //在一次回环之后，第一帧或许不在起始位置了
    cv::Mat Two = vpKFs[0]->GetPoseInverse();
    
    ofstream f;
    f.open(filename.c_str());
    f << fixed;
    
    // Frame pose is stored relative to its reference keyframe (which is optimized by BA and pose graph).
    //帧的姿态是相对于它的参考关键帧储存的（这是由BA和姿态图优化）
    // We need to get first the keyframe pose and then concatenate the relative transformation.
    //我们需要首先得到参考帧位姿并且然后链接相应的转换
    // Frames not localized (tracking failure) are not saved.
    //追踪失败不被保存
    // For each frame we have a reference keyframe (lRit), the timestamp (lT) and a flag
    //对于每一帧我们有一个参考帧，这个时间标记和一个标志
    // which is true when tracking failed (lbL).
    //如果追踪失败了，ibl值为true
    list<ORB_SLAM2::KeyFrame*>::iterator lRit = mpTracker->mlpReferences.begin();//当前帧
    list<double>::iterator lT = mpTracker->mlFrameTimes.begin();//时间标记
    list<bool>::iterator lbL = mpTracker->mlbLost.begin();//flag
    for(list<cv::Mat>::iterator lit=mpTracker->mlRelativeFramePoses.begin(),
        lend=mpTracker->mlRelativeFramePoses.end();lit!=lend;lit++, lRit++, lT++, lbL++)
    {
        if(*lbL)
            continue;
    
        KeyFrame* pKF = *lRit;
    
        cv::Mat Trw = cv::Mat::eye(4,4,CV_32F);
    
        // If the reference keyframe was culled, traverse the spanning tree to get a suitable keyframe.
        //如果关键帧被剔除了，遍历生成树去得到一个适合的关键帧
        while(pKF->isBad())
        {
            Trw = Trw*pKF->mTcp;
            pKF = pKF->GetParent();
        }
    
        Trw = Trw*pKF->GetPose()*Two;
    
        cv::Mat Tcw = (*lit)*Trw;
        cv::Mat Rwc = Tcw.rowRange(0,3).colRange(0,3).t();
        cv::Mat twc = -Rwc*Tcw.rowRange(0,3).col(3);
    
        vector<float> q = Converter::toQuaternion(Rwc);
    
        f << setprecision(6) << *lT << " " <<  setprecision(9) << twc.at<float>(0) << " " << twc.at<float>(1) << " " << twc.at<float>(2) << " " << q[0] << " " << q[1] << " " << q[2] << " " << q[3] << endl;
    }
    f.close();
    cout << endl << "trajectory saved!" << endl;
    }
    
    
    void System::SaveKeyFrameTrajectoryTUM(const string &filename)//保存关键帧轨迹 ros_rgbd.cc调用的
    {
    cout << endl << "Saving keyframe trajectory to " << filename << " ..." << endl;
    
    vector<KeyFrame*> vpKFs = mpMap->GetAllKeyFrames();//关键帧
    sort(vpKFs.begin(),vpKFs.end(),KeyFrame::lId);//排序
    
    // Transform all keyframes so that the first keyframe is at the origin.
    // After a loop closure the first keyframe might not be at the origin.
    //cv::Mat Two = vpKFs[0]->GetPoseInverse();
    
    ofstream f;
    f.open(filename.c_str());
    f << fixed;
    
    for(size_t i=0; i<vpKFs.size(); i++)
    {
        KeyFrame* pKF = vpKFs[i];
    
       // pKF->SetPose(pKF->GetPose()*Two);
    
        if(pKF->isBad())
            continue;
        //得到R，t
        cv::Mat R = pKF->GetRotation().t();
        vector<float> q = Converter::toQuaternion(R);
        cv::Mat t = pKF->GetCameraCenter();
        f << setprecision(6) << pKF->mTimeStamp << setprecision(7) << " " << t.at<float>(0) << " " << t.at<float>(1) << " " << t.at<float>(2)
          << " " << q[0] << " " << q[1] << " " << q[2] << " " << q[3] << endl;//保存
    
    }
    
    f.close();
    cout << endl << "trajectory saved!" << endl;
    }