Method DetectCandidates

src/KeyFrameDatabase.cc:228–466

}

void KeyFrameDatabase::DetectCandidates(KeyFrame* pKF, float minScore,vector<KeyFrame*>& vpLoopCand, vector<KeyFrame*>& vpMergeCand)
{
    set<KeyFrame*> spConnectedKeyFrames = pKF->GetConnectedKeyFrames();
    list<KeyFrame*> lKFsSharingWordsLoop,lKFsSharingWordsMerge;

    // Search all keyframes that share a word with current keyframes
    // Discard keyframes connected to the query keyframe
    {
        unique_lock<mutex> lock(mMutex);

        for(DBoW2::BowVector::const_iterator vit=pKF->mBowVec.begin(), vend=pKF->mBowVec.end(); vit != vend; vit++)
        {
            list<KeyFrame*> &lKFs = mvInvertedFile[vit->first];

            for(list<KeyFrame*>::iterator lit=lKFs.begin(), lend= lKFs.end(); lit!=lend; lit++)
            {
                KeyFrame* pKFi=*lit;
                if(pKFi->GetMap()==pKF->GetMap()) // For consider a loop candidate it a candidate it must be in the same map
                {
                    if(pKFi->mnLoopQuery!=pKF->mnId)
                    {
                        pKFi->mnLoopWords=0;
                        if(!spConnectedKeyFrames.count(pKFi))
                        {
                            pKFi->mnLoopQuery=pKF->mnId;
                            lKFsSharingWordsLoop.push_back(pKFi);
                        }
                    }
                    pKFi->mnLoopWords++;
                }
                else if(!pKFi->GetMap()->IsBad())
                {
                    if(pKFi->mnMergeQuery!=pKF->mnId)
                    {
                        pKFi->mnMergeWords=0;
                        if(!spConnectedKeyFrames.count(pKFi))
                        {
                            pKFi->mnMergeQuery=pKF->mnId;
                            lKFsSharingWordsMerge.push_back(pKFi);
                        }
                    }
                    pKFi->mnMergeWords++;
                }
            }
        }
    }

    if(lKFsSharingWordsLoop.empty() && lKFsSharingWordsMerge.empty())
        return;

    if(!lKFsSharingWordsLoop.empty())
    {
        list<pair<float,KeyFrame*> > lScoreAndMatch;

        // Only compare against those keyframes that share enough words
        int maxCommonWords=0;
        for(list<KeyFrame*>::iterator lit=lKFsSharingWordsLoop.begin(), lend= lKFsSharingWordsLoop.end(); lit!=lend; lit++)
        {