DBoW的编译和运行

本文主要分享了在Linux下DboW2和DBoW3的编译和示例运行。

安装依赖

1. 安装 OpenCV 3.4.13。

   OpenCV4因为安全性提升、解析器更复杂、兼容性增强等原因导致其读取*.yml文件的速度要远慢于OpenCV3。

2. 安装Boost库（DBoW2需要）：

   sudo apt-get update
   sudo apt-get install libboost-all-dev

3. 完成。

DboW3

1. 克隆代码：

   cd your_floder
   git clone https://github.com/rmsalinas/DBow3.git
   cd DBow3

2. （可选）在根目录的CMakeLists.txt中Line53 find_package(OpenCV REQUIRED) 前指定OpenCV的路径：

   set(OpenCV_DIR /usr/local/opencv/opencv3413/share/OpenCV) 

3. 编译代码：

   mkdir build
   cd build
   cmake .. -DBUILD_TESTS=ON
   make -j8

4. 运行示例：

   # 把in.yml转存为DBoW3支持的二进制格式out.dbow以加快词袋的读取速度。
   ./tests/test_iobinary in.yml out.dbow

5. 完成。

DBoW2

1. 克隆代码：

   git clone https://github.com/raulmur/ORB_SLAM2.git
   cd ORB_SLAM2
   git fetch origin pull/21/head:pr-21
   git checkout pr-21

   后面只需要Thirdparty/下的DBoW2文件夹。

   这里使用了ORB-SLAM2中pr-21的修改后的DBoW2，其中添加了加载和保存二进制词袋的功能。主要修改文件为Thirdparty/DBoW2/DBoW2/TemplatedVocabulary.h，添加的内容为：

   /**
      * Loads the vocabulary from a binary file
      * @param filename
      */
   bool loadFromBinaryFile(const std::string &filename);
   
   /**
      * Saves the vocabulary into a binary file
      * @param filename
      */
   void saveToBinaryFile(const std::string &filename) const; 
   
   template<class TDescriptor, class F>
   bool TemplatedVocabulary<TDescriptor,F>::loadFromBinaryFile(const std::string &filename) {
     fstream f;
     f.open(filename.c_str(), ios_base::in|ios::binary);
     unsigned int nb_nodes, size_node;
     f.read((char*)&nb_nodes, sizeof(nb_nodes));
     f.read((char*)&size_node, sizeof(size_node));
     f.read((char*)&m_k, sizeof(m_k));
     f.read((char*)&m_L, sizeof(m_L));
     f.read((char*)&m_scoring, sizeof(m_scoring));
     f.read((char*)&m_weighting, sizeof(m_weighting));
     createScoringObject();
   
     m_words.clear();
     m_words.reserve(pow((double)m_k, (double)m_L + 1));
     m_nodes.clear();
     m_nodes.resize(nb_nodes+1);
     m_nodes[0].id = 0;
     char buf[size_node]; int nid = 1;
     while (!f.eof()) {
   	f.read(buf, size_node);
   	m_nodes[nid].id = nid;
   	// FIXME
   	const int* ptr=(int*)buf;
   	m_nodes[nid].parent = *ptr;
   	//m_nodes[nid].parent = *(const int*)buf;
   	m_nodes[m_nodes[nid].parent].children.push_back(nid);
   	m_nodes[nid].descriptor = cv::Mat(1, F::L, CV_8U);
   	memcpy(m_nodes[nid].descriptor.data, buf+4, F::L);
   	m_nodes[nid].weight = *(float*)(buf+4+F::L);
   	if (buf[8+F::L]) { // is leaf
   	  int wid = m_words.size();
   	  m_words.resize(wid+1);
   	  m_nodes[nid].word_id = wid;
   	  m_words[wid] = &m_nodes[nid];
   	}
   	else
   	  m_nodes[nid].children.reserve(m_k);
   	nid+=1;
     }
     f.close();
     return true;
   }
   
   template<class TDescriptor, class F>
   void TemplatedVocabulary<TDescriptor,F>::saveToBinaryFile(const std::string &filename) const {
     fstream f;
     f.open(filename.c_str(), ios_base::out|ios::binary);
   f.open ( filename.c_str (),ios_base::out|ios::binary);
     unsigned int nb_nodes = m_nodes.size();
     float _weight;
     unsigned int size_node = sizeof(m_nodes[0].parent) + F::L*sizeof(char) + sizeof(_weight) + sizeof(bool);
     f.write((char*)&nb_nodes, sizeof(nb_nodes));
     f.write((char*)&size_node, sizeof(size_node));
     f.write((char*)&m_k, sizeof(m_k));
     f.write((char*)&m_L, sizeof(m_L));
     f.write((char*)&m_scoring, sizeof(m_scoring));
     f.write((char*)&m_weighting, sizeof(m_weighting));
     for(size_t i=1; i<nb_nodes;i++) {
   	const Node& node = m_nodes[i];
   	f.write((char*)&node.parent, sizeof(node.parent));
   	f.write((char*)node.descriptor.data, F::L);
   	_weight = node.weight; f.write((char*)&_weight, sizeof(_weight));
   	bool is_leaf = node.isLeaf(); f.write((char*)&is_leaf, sizeof(is_leaf)); // i put this one at the end for alignement....
     }
     f.close();
   }

2. 在DBoW2/DBoW2/里添加demo.cpp文件，文件内容为：

   /**
    * File: Demo.cpp
    * Date: November 2011
    * Author: Dorian Galvez-Lopez
    * Description: demo application of DBoW2
    * License: see the LICENSE.txt file
    */
   
   #include <iostream>
   #include <vector>
   #include <string>
   
   // DBoW2
   #include "FORB.h"
   #include "TemplatedVocabulary.h"
   
   // OpenCV
   #include <opencv2/core.hpp>
   #include <opencv2/highgui.hpp>
   #include <opencv2/features2d.hpp>
   
   
   using namespace DBoW2;
   using namespace std;
   
   //command line parser
   class CmdLineParser{int argc; char **argv; public: CmdLineParser(int _argc,char **_argv):argc(_argc),argv(_argv){}  bool operator[] ( string param ) {int idx=-1;  for ( int i=0; i<argc && idx==-1; i++ ) if ( string ( argv[i] ) ==param ) idx=i;    return ( idx!=-1 ) ;    } string operator()(string param,string defvalue="-1"){int idx=-1;    for ( int i=0; i<argc && idx==-1; i++ ) if ( string ( argv[i] ) ==param ) idx=i; if ( idx==-1 ) return defvalue;   else  return ( argv[  idx+1] ); }};
   
   bool has_suffix(const std::string &str, const std::string &suffix) {
       std::size_t index = str.find(suffix, str.size() - suffix.size());
       return (index != std::string::npos);
   }
   
   int main(int argc,char **argv)
   {
       try{
           CmdLineParser cml(argc,argv);
           if (cml["-h"] || argc!=3){
               cerr<<"Usage:  in.yml out.bin"<<endl;
               return -1;
           }
           DBoW2::TemplatedVocabulary<DBoW2::FORB::TDescriptor, DBoW2::FORB> voc;
           if (has_suffix(argv[1], ".txt")) {
             voc.loadFromTextFile(argv[1]);
             cout<<"loaded"<<endl;
             voc.saveToBinaryFile(argv[2]);
             cout<<"saved"<<endl;
           } else if (has_suffix(argv[1], ".yml")) {
             voc.load(argv[1]);
             cout<<"loaded"<<endl;
             voc.saveToBinaryFile(argv[2]);
             cout<<"saved"<<endl;
           } else {
             voc.loadFromBinaryFile(argv[1]);
             cout<<"loaded"<<endl;
           }
       }catch(std::exception &ex){
           cerr<<ex.what()<<endl;
       }
   
       return 0;
   }

3. 修改根目录DBoW2/的CMakeLists.txt文件：

   # 在Line27 `find_package(OpenCV 3.0 QUIET)` 前指定OpenCV的路径：
   set(OpenCV_DIR /usr/local/opencv/opencv3413/share/OpenCV) 
   
   # 在最后一行添加：
   add_executable(demo DBoW2/demo.cpp)
   target_link_libraries(demo DBoW2 ${OpenCV_LIBS})
   MESSAGE( STATUS "OPENCV_DIR= ${OpenCV_DIR} VERSION=${OpenCV_VERSION}" )

4. 编译代码：

   cd DBoW2
   mkdir build
   cd build
   cmake .. 
   make -j8

5. 运行示例：

   ./demo in.yml out.bin

6. 完成。