看完回环检测的代码，我们重新回到主线程：

correctPoses()

void correctPoses(){
    	if (aLoopIsClosed == true){
            recentCornerCloudKeyFrames. clear();
            recentSurfCloudKeyFrames.   clear();
            recentOutlierCloudKeyFrames.clear();
            // update key poses
                int numPoses = isamCurrentEstimate.size();
            for (int i = 0; i < numPoses; ++i){
            cloudKeyPoses3D->points[i].x = isamCurrentEstimate.at<Pose3>(i).translation().y();
            cloudKeyPoses3D->points[i].y = isamCurrentEstimate.at<Pose3>(i).translation().z();
            cloudKeyPoses3D->points[i].z = isamCurrentEstimate.at<Pose3>(i).translation().x();

            cloudKeyPoses6D->points[i].x = cloudKeyPoses3D->points[i].x;
            cloudKeyPoses6D->points[i].y = cloudKeyPoses3D->points[i].y;
            cloudKeyPoses6D->points[i].z = cloudKeyPoses3D->points[i].z;
            cloudKeyPoses6D->points[i].roll  = isamCurrentEstimate.at<Pose3>(i).rotation().pitch();
            cloudKeyPoses6D->points[i].pitch = isamCurrentEstimate.at<Pose3>(i).rotation().yaw();
            cloudKeyPoses6D->points[i].yaw   = isamCurrentEstimate.at<Pose3>(i).rotation().roll();
            }

            aLoopIsClosed = false;
        }
    }

correctPoses()主要用来判断是否发生了回环检测，如果有回环就更新当前关键帧的位姿和位置。

publishTF()

void publishTF(){

        geometry_msgs::Quaternion geoQuat = tf::createQuaternionMsgFromRollPitchYaw
                                  (transformAftMapped[2], -transformAftMapped[0], -transformAftMapped[1]);

        odomAftMapped.header.stamp = ros::Time().fromSec(timeLaserOdometry);
        odomAftMapped.pose.pose.orientation.x = -geoQuat.y;
        odomAftMapped.pose.pose.orientation.y = -geoQuat.z;
        odomAftMapped.pose.pose.orientation.z = geoQuat.x;
        odomAftMapped.pose.pose.orientation.w = geoQuat.w;
        odomAftMapped.pose.pose.position.x = transformAftMapped[3];
        odomAftMapped.pose.pose.position.y = transformAftMapped[4];
        odomAftMapped.pose.pose.position.z = transformAftMapped[5];

将生成的四元数信息填充到 odomAftMapped.pose.pose.orientation。
将位置 transformAftMapped[3], [4], [5] 赋值给 odomAftMapped.pose.pose.position，代表的是更新后位姿的平移部分。

        odomAftMapped.twist.twist.angular.x = transformBefMapped[0];
        odomAftMapped.twist.twist.angular.y = transformBefMapped[1];
        odomAftMapped.twist.twist.angular.z = transformBefMapped[2];
        odomAftMapped.twist.twist.linear.x = transformBefMapped[3];
        odomAftMapped.twist.twist.linear.y = transformBefMapped[4];
        odomAftMapped.twist.twist.linear.z = transformBefMapped[5];

将 transformBefMapped 中的角速度和线速度信息发布到 odomAftMapped.twist.twist 中。
angular 表示旋转速度，linear 表示平移速度，这里直接从 transformBefMapped 获取数据。
transformBefMapped 是上一帧的transformSum!!!

        pubOdomAftMapped.publish(odomAftMapped);

        aftMappedTrans.stamp_ = ros::Time().fromSec(timeLaserOdometry);
        aftMappedTrans.setRotation(tf::Quaternion(-geoQuat.y, -geoQuat.z, geoQuat.x, geoQuat.w));
        aftMappedTrans.setOrigin(tf::Vector3(transformAftMapped[3], transformAftMapped[4], transformAftMapped[5]));
        tfBroadcaster.sendTransform(aftMappedTrans);
    }

 publishKeyPosesAndFrames()

void publishKeyPosesAndFrames(){

        if (pubKeyPoses.getNumSubscribers() != 0){
            sensor_msgs::PointCloud2 cloudMsgTemp;
            pcl::toROSMsg(*cloudKeyPoses3D, cloudMsgTemp);
            cloudMsgTemp.header.stamp = ros::Time().fromSec(timeLaserOdometry);
            cloudMsgTemp.header.frame_id = "camera_init";
            pubKeyPoses.publish(cloudMsgTemp);
        }

        if (pubRecentKeyFrames.getNumSubscribers() != 0){
            sensor_msgs::PointCloud2 cloudMsgTemp;
            pcl::toROSMsg(*laserCloudSurfFromMapDS, cloudMsgTemp);
            cloudMsgTemp.header.stamp = ros::Time().fromSec(timeLaserOdometry);
            cloudMsgTemp.header.frame_id = "camera_init";
            pubRecentKeyFrames.publish(cloudMsgTemp);
        }

        if (pubRegisteredCloud.getNumSubscribers() != 0){
            pcl::PointCloud<PointType>::Ptr cloudOut(new pcl::PointCloud<PointType>());
            PointTypePose thisPose6D = trans2PointTypePose(transformTobeMapped);
            *cloudOut += *transformPointCloud(laserCloudCornerLastDS,  &thisPose6D);
            *cloudOut += *transformPointCloud(laserCloudSurfTotalLast, &thisPose6D);
            
            sensor_msgs::PointCloud2 cloudMsgTemp;
            pcl::toROSMsg(*cloudOut, cloudMsgTemp);
            cloudMsgTemp.header.stamp = ros::Time().fromSec(timeLaserOdometry);
            cloudMsgTemp.header.frame_id = "camera_init";
            pubRegisteredCloud.publish(cloudMsgTemp);
        } 
    }

发布的数据有历史关键帧位置数据cloudKeyPoses3D，这就是rviz里面轨迹的那条线。

laserCloudSurfFromMapDS是子地图数据。

laserCloudCornerLastDS等是当前帧的角点经位姿变化到地图坐标系下的点云数据。

clearCloud()

void clearCloud(){
        laserCloudCornerFromMap->clear();
        laserCloudSurfFromMap->clear();  
        laserCloudCornerFromMapDS->clear();
        laserCloudSurfFromMapDS->clear();   
    }

至此，lego-loam主要的代码就都注释完啦！！！完结撒花，咱们lio-sam再见！！

ヾ(￣▽￣)Bye~Bye~