Getting the last n keyframes in real time

[IslamAAli]

Hello,

I am running ORB-SLAM3 in mono-inertial mode on EuroC dataset. For each frame processed, I want to get the last 20 keyframes.

What I do is that, I get the active map from Atlas and then extract the keyframes in that active map. The problem is that when I do this, I get only a few keyframes compared to the total number of keyframes shown in the visualization window. For example, usually, it is only 2 keyframes up to 9 or so.

The following is the code I use in a function that is called inside the euroc mono_inertial main

allPoses.clear();

// current pose info
vector<double> curr_pose;
curr_pose.reserve(8);

// get the active map (current map, since we are working in real time)
Map* pActiveMap = mpAtlas->GetCurrentMap();

if (pActiveMap == NULL)
{
    cout << "TEST: active map is null" << endl;
}

// get all keyframes and sort them using their ID
vector<KeyFrame*> vpKFs = pActiveMap->GetAllKeyFrames();
sort(vpKFs.begin(),vpKFs.end(),KeyFrame::lId);

// 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.
for(size_t i=0; i<vpKFs.size(); i++)
{
    curr_pose.clear();
    curr_pose.reserve(8);

    KeyFrame* pKF = vpKFs[i];

    // if keyframe is culled , go to the next one
    if(!pKF || pKF->isBad())
        continue;

    // else, get info of the current transform of the pose
    Sophus::SE3f T_base;
    Eigen::Quaternionf q;
    Eigen::Vector3f t;

    if (mSensor == IMU_MONOCULAR || mSensor == IMU_STEREO || mSensor==IMU_RGBD)
    {
        T_base = pKF->GetImuPose();   
    }
    else
    {
        T_base = pKF->GetPoseInverse();
    }
    q = T_base.unit_quaternion();
    t = T_base.translation();

    std::vector<double> currPose;

    // push all pose transform data to vector
    currPose.push_back(1e9*pKF->mTimeStamp);
    currPose.push_back(t(0));
    currPose.push_back(t(1));
    currPose.push_back(t(2));
    currPose.push_back(q.x());
    currPose.push_back(q.y());
    currPose.push_back(q.z());
    currPose.push_back(q.w());

    // submit this pose to poses repository
    allPoses.push_back(currPose);
}