因项目要求要跑ORB－SLAM3,在安装和测试的过程中遇到了很多问题，特此在这里记录一下：
一．硬件介绍：
硬件：Intel Realsense D455

二．编译：
关于Pangolin:
https://blog.csdn.net/Robert_Q/article/details/121690089

三．运行Example
目前只跑了Examples/Stereo,因此在这里主要记录这里面的问题

1. 修改配置文件
2. 修改Settings.cc
   在Settings.cc中存在一处逻辑错误，会导致在加载camera2参数时报Segmentation fault.
   修改前：

// 修改此方法ostream &operator<<(std::ostream& output, const Settings& settings){output << "SLAM settings: " << endl;......if(settings.sensor_ == System::STEREO || settings.sensor_ == System::IMU_STEREO){output << "\t-Camera 2 parameters (";if(settings.cameraType_ == Settings::PinHole || settings.cameraType_ ==  Settings::Rectified){cout<<"Pinhole"<size(); i++){cout<getParameter(i)<getParameter(i);}output << " ]" << endl;if(!settings.vPinHoleDistorsion2_.empty()){output << "\t-Camera 2 distortion parameters: [ ";for(float d : settings.vPinHoleDistorsion2_){output << " " << d;}output << " ]" << endl;}}

修改后：

    ostream &operator<<(std::ostream& output, const Settings& settings){output << "SLAM settings: " << endl;......if(settings.cameraType_ == Settings::PinHole){output << ")" << ": [";for(size_t i = 0; i < settings.originalCalib2_->size(); i++){output << " " << settings.originalCalib2_->getParameter(i);}output << " ]" << endl;}else if(settings.cameraType_ == Settings::Rectified){output << ")" << ": [";for(size_t i = 0; i < settings.originalCalib1_->size(); i++){output << " " << settings.originalCalib1_->getParameter(i);}output << " ]" << endl;}

参考自:参考此处

3. 修改System.cc
   问题１：在保存地图时，经常会出现Segmentation fault，导致地图无法保存，在debug了好久后，目前找到了可能的原因：
   在UI界面点击stop后，stereo_realsense_D435i.cc中的while (!SLAM.isShutDown())会返回mbShutDown这个flag的状态，而这个flag是在System::shutdown()中进行修改的．

void System::Shutdown()
{{unique_lock lock(mMutexReset);mbShutDown = true;}cout << "Shutdown" << endl;mpLocalMapper->RequestFinish();mpLoopCloser->RequestFinish();...

a. shutdown()是注册在界面端的函数．在界面点击stop()后， mbShutDown 立刻会被设置为 true;
b. 同时在./Examples/Stereo/stereo_realsense_D435i.cc中的while (!SLAM.isShutDown())会检查mbShutDown的值．当mbShutDown==true时，退出while循环. 推出while循环后，后面已无可执行的命令，整个程序退出，SLAM对象销毁．
c. 但是当地图文件很大时，注册在界面端的函数依旧在执行，最后在SaveAtlas()时，会访问SLAM对象中的一些成员，如mStrVocabularyFilePath变量,但此时SLAM已经被销毁，最后访问变量出错，导致Segmentation fault.

修改

void System::Shutdown()
{{unique_lock lock(mMutexReset);}cout << "Shutdown" << endl;mpLocalMapper->RequestFinish();mpLoopCloser->RequestFinish();...if(!mStrSaveAtlasToFile.empty()){Verbose::PrintMess("Atlas saving to file " + mStrSaveAtlasToFile, Verbose::VERBOSITY_NORMAL);SaveAtlas(FileType::BINARY_FILE);}/*if(mpViewer)pangolin::BindToContext("ORB-SLAM2: Map Viewer");*/
#ifdef REGISTER_TIMESmpTracker->PrintTimeStats();
#endifmbShutDown = true;
}

将mbShutDown = true;放在程序的最后，在执行完地图保存后，再修改flag.