添加key_frame_info.msg消息
新建.msg文件,內容填寫為:
# Cloud Info
Header header # cloud messages
sensor_msgs/PointCloud2 key_frame_cloud_ori
sensor_msgs/PointCloud2 key_frame_cloud_transed
sensor_msgs/PointCloud2 key_frame_poses
其中key_frame_cloud_ori為原始點云(需要包含行號ring),key_frame_cloud_transed 為利用SLAM轉換到統一坐標系后的點云.key_frame_poses為SLAM輸出的位姿.
把構建好的key_frame_info.msg文件放在msg文件夾下,隨后,在CMakeLists.txt文件中添加
add_message_files(FILESkey_frame_info.msg
)
并修改generate_messages,在generate_messages中添加sensor_msgs
generate_messages(DEPENDENCIESgeometry_msgssensor_msgs
)
編譯,會生成key_frame_info.h文件.
之后在common_lib.h文件中添加key_frame_info.h文件的引用,即可添加使用自定義的key_frame_info消息類型
#include <point_lio/key_frame_info.h>
添加自定義數據結構PointXYZIRPYT,并重命名為PointTypePose(用于存儲X,Y,Z,Roll,Pitch,Yaw)
找到preprocess.h頭文件,在velodyne_ros,hesai_ros,ouster_ros等一系列數據結構后面添加下述代碼:
/** A point cloud type that has 6D pose info ([x,y,z,roll,pitch,yaw] intensity is time stamp)*/
struct PointXYZIRPYT
{PCL_ADD_POINT4DPCL_ADD_INTENSITY; // preferred way of adding a XYZ+paddingfloat roll;float pitch;float yaw;double time;EIGEN_MAKE_ALIGNED_OPERATOR_NEW // make sure our new allocators are aligned
} EIGEN_ALIGN16; // enforce SSE padding for correct memory alignmentPOINT_CLOUD_REGISTER_POINT_STRUCT (PointXYZIRPYT,(float, x, x) (float, y, y)(float, z, z) (float, intensity, intensity)(float, roll, roll) (float, pitch, pitch) (float, yaw, yaw)(double, time, time))typedef PointXYZIRPYT PointTypePose;
添加額外的變量
注意:本文以ouster lidar為例,所以在變量命名過程中大多貼近Ouster
- ouster_buffer (存儲ouster原始點云類型指針),ouster_undistort (存儲ouster單幀原始點云數據,從ouster_buffer提取數據),key_frame_poses_data (存儲PointLIO計算的關鍵幀位姿,點類型為前述定義的PointTypePose)
在li_initialization.h頭文件中添加聲明:
// set the ouster data buffer
extern std::deque<pcl::PointCloud<ouster_ros::Point>::Ptr> ouster_buffer;
// set the ouster point cloud and the key frame pose
extern pcl::PointCloud<ouster_ros::Point>::Ptr ouster_undistort;
// set the key frame pose
extern pcl::PointCloud<PointTypePose>::Ptr key_frame_poses_data;
在li_initialization.cpp頭文件中添加定義:
// set the ouster data buffer
std::deque<pcl::PointCloud<ouster_ros::Point>::Ptr> ouster_buffer;
// set the ouster point cloud and the key frame pose
pcl::PointCloud<ouster_ros::Point>::Ptr ouster_undistort(new pcl::PointCloud<ouster_ros::Point>());
// set the key frame pose
pcl::PointCloud<PointTypePose>::Ptr key_frame_poses_data(new pcl::PointCloud<PointTypePose>());
上述兩部分均放在了lidar_buffer, time_buffer, imu_deque等變量之后.
2. pubKeyFrameInfo變量,以發布關鍵幀相關信息
在laserMapping.cpp文件中添加,定義如下:
ros::Publisher pubKeyFrameInfo = nh.advertise<point_lio::key_frame_info> ("/point_lio/key_frame_info", 100000);
即發布"/point_lio/key_frame_info"消息,存儲關鍵幀位置的原始點云,轉換到world坐標系的點云,關鍵幀位姿等信息.
添加自定義函數
- 在laserMapping.cpp文件中添加發布關鍵幀信息函數publish_key_frame_info:
/******* Publish Key Frame Info *******/
void publish_key_frame_info(const ros::Publisher pubKeyFrameInfo)
{// set the key frame infopoint_lio::key_frame_info keyframeInfo;keyframeInfo.header.stamp = ros::Time().fromSec(lidar_end_time);keyframeInfo.header.frame_id = "camera_init";pcl::PointCloud<ouster_ros::Point>::Ptr cloud(new pcl::PointCloud<ouster_ros::Point>);// transformed the ouster dataint size = ouster_undistort->points.size();pcl::PointCloud<ouster_ros::Point>::Ptr ousterCloudWorld(new pcl::PointCloud<ouster_ros::Point>(size,1));for (int i = 0; i < size; i++){pointBodyToWorld(&ouster_undistort->points[i], &ousterCloudWorld->points[i]);(&ouster_undistort->points[i], &ousterCloudWorld->points[i]);}// get the original Ouster datasensor_msgs::PointCloud2 ousterCloudOriMsg;pcl::toROSMsg(*ouster_undistort, ousterCloudOriMsg);ousterCloudOriMsg.header.stamp = ros::Time().fromSec(lidar_end_time);ousterCloudOriMsg.header.frame_id = "camera_init";// get the transformed Ouster datasensor_msgs::PointCloud2 ousterCloudWorldMsg;pcl::toROSMsg(*ousterCloudWorld, ousterCloudWorldMsg);ousterCloudWorldMsg.header.stamp = ros::Time().fromSec(lidar_end_time);ousterCloudWorldMsg.header.frame_id = "camera_init";// get current transtformationstd::vector<double> curr_pose = getKeyTransformation();// set the key frame Info msg data (include original data and tranformed to world)keyframeInfo.key_frame_cloud_ori = ousterCloudOriMsg;keyframeInfo.key_frame_cloud_transed = ousterCloudWorldMsg;/*** slected the keyframe at 1Hz ***/static int jjj = 0;if (jjj % 10 == 0) {// stack the pose at 1 HzPointTypePose pj;pj.x = curr_pose[0]; pj.y = curr_pose[1]; pj.z = curr_pose[2];pj.roll = curr_pose[3]; pj.pitch = curr_pose[4]; pj.yaw = curr_pose[5];key_frame_poses_data->push_back(pj);// convert the point cloud into sensor messagesensor_msgs::PointCloud2 keyFramePosesMsg;keyFramePosesMsg.header.stamp = ros::Time().fromSec(lidar_end_time);keyFramePosesMsg.header.frame_id = "camera_init";pcl::toROSMsg(*key_frame_poses_data, keyFramePosesMsg);// set the data of key frame infokeyframeInfo.key_frame_poses = keyFramePosesMsg;pubKeyFrameInfo.publish(keyframeInfo);}jjj++;
}
- 在Estimator.h頭文件中添加轉換點坐標系函數,專門針對Ouster類型進行處理:
// transform the ouster point from body to world
void pointBodyToWorld(ouster_ros::Point const * const pi, ouster_ros::Point * const po);
隨后在對應的Estimator.cpp頭文件中添加函數定義
// transform the ouster point from body to world
void pointBodyToWorld(ouster_ros::Point const * const pi, ouster_ros::Point * const po)
{if (pi == nullptr || po == nullptr) {std::cerr << "Error: Null pointer passed to RGBpointBodyToWorld!" << std::endl;return;}V3D p_body(pi->x, pi->y, pi->z);V3D p_global;if (extrinsic_est_en){ if (!use_imu_as_input){p_global = kf_output.x_.rot * (kf_output.x_.offset_R_L_I * p_body + kf_output.x_.offset_T_L_I) + kf_output.x_.pos;}else{p_global = kf_input.x_.rot * (kf_input.x_.offset_R_L_I * p_body + kf_input.x_.offset_T_L_I) + kf_input.x_.pos;}}else{if (!use_imu_as_input){p_global = kf_output.x_.rot * (Lidar_R_wrt_IMU * p_body + Lidar_T_wrt_IMU) + kf_output.x_.pos; // .normalized()}else{p_global = kf_input.x_.rot * (Lidar_R_wrt_IMU * p_body + Lidar_T_wrt_IMU) + kf_input.x_.pos; // .normalized()}}po->x = p_global(0);po->y = p_global(1);po->z = p_global(2);// copy pipo->intensity = pi->intensity;po->t = pi->t;po->reflectivity = pi->reflectivity;po->ring = pi->ring;po->ambient = pi->ambient;po->range = pi->range;}
- 在Estimator.h頭文件中添加獲取當前變換的函數,能夠獲取PointLIO系統當前處理的坐標系變換,輸出為X,Y,Z,Roll,Pitch,Yaw,并存儲在一個vector中:
聲明如下:
// get current key transformation data
std::vector<double> getKeyTransformation();
在Estimator.cpp文件中的對應定義如下:
// get current key transformation data
std::vector<double> getKeyTransformation()
{SO3 ROT;vect3 TRANS;if (extrinsic_est_en){ if (!use_imu_as_input){ROT = kf_output.x_.rot * kf_output.x_.offset_R_L_I;TRANS = kf_output.x_.rot * kf_output.x_.offset_T_L_I + kf_output.x_.pos;// p_global = kf_output.x_.rot * (kf_output.x_.offset_R_L_I * p_body + kf_output.x_.offset_T_L_I) + kf_output.x_.pos;}else{ROT = kf_input.x_.rot * kf_input.x_.offset_R_L_I;TRANS = kf_input.x_.rot * kf_input.x_.offset_T_L_I + kf_input.x_.pos;// p_global = kf_input.x_.rot * (kf_input.x_.offset_R_L_I * p_body + kf_input.x_.offset_T_L_I) + kf_input.x_.pos;}}else{if (!use_imu_as_input){ROT = kf_output.x_.rot * Lidar_R_wrt_IMU;TRANS = kf_output.x_.rot * Lidar_T_wrt_IMU + kf_output.x_.pos;// p_global = kf_output.x_.rot * (Lidar_R_wrt_IMU * p_body + Lidar_T_wrt_IMU) + kf_output.x_.pos; // .normalized()}else{ROT = kf_input.x_.rot * Lidar_R_wrt_IMU;TRANS = kf_input.x_.rot * Lidar_T_wrt_IMU + kf_input.x_.pos;// p_global = kf_input.x_.rot * (Lidar_R_wrt_IMU * p_body + Lidar_T_wrt_IMU) + kf_input.x_.pos; // .normalized()}}// create an Affine variableEigen::Affine3d affine = Eigen::Affine3d::Identity();affine.linear() = ROT;affine.translation() = TRANS;// convert to the x y z roll pitch yaw variablesstd::vector<double> transformed_para;double x, y, z, roll, pitch, yaw;pcl::getTranslationAndEulerAngles(affine, x, y, z, roll, pitch, yaw);// return datatransformed_para.push_back(x); transformed_para.push_back(y); transformed_para.push_back(z);transformed_para.push_back(roll); transformed_para.push_back(pitch); transformed_para.push_back(yaw);return transformed_para;
}
添加處理流程
首先,要能夠用ouster_buffer 在standard_pcl_cbk回調函數中接收到ouster數據消息,修改如下:
// 修改前if (ptr->points.size() > 0){lidar_buffer.emplace_back(ptr);time_buffer.emplace_back(msg->header.stamp.toSec());}
// 修改后if (ptr->points.size() > 0){lidar_buffer.emplace_back(ptr);time_buffer.emplace_back(msg->header.stamp.toSec());// get the ouster datapcl::PointCloud<ouster_ros::Point>::Ptr ouster_data(new pcl::PointCloud<ouster_ros::Point>());pcl::fromROSMsg(*msg, *ouster_data);ouster_buffer.push_back(ouster_data);}
隨后,在sync_packages函數中,從ouster_buffer提取數據,到ouster_undistort變量:
// 修改前if (lidar_buffer.empty() || imu_deque.empty()){return false;}
// 修改后if (lidar_buffer.empty() || imu_deque.empty() || ouster_buffer.empty()){return false;}
隨后,提取數據:
/*** push a lidar scan ***/if(!lidar_pushed){lose_lid = false;meas.lidar = lidar_buffer.front();meas.lidar_beg_time = time_buffer.front();//在這個位置提取數據:ouster_undistort = ouster_buffer.front();
在函數的最后,把ouster_buffer變量的頭部數據pop掉:
lidar_buffer.pop_front();time_buffer.pop_front();// 添加代碼ouster_buffer.pop_front();lidar_pushed = false;imu_pushed = false;return true;
通過上述過程,我們能夠在pointlio系統運行過程中不斷獲取ouster_undistort原始點云,回到laserMapping.cpp主函數中,我們在發布消息的位置添加我們自定義的關鍵幀信息發布函數publish_key_frame_info.
添加如下:
/******* Publish points *******/if (path_en) publish_path(pubPath);if (scan_pub_en || pcd_save_en) publish_frame_world(pubLaserCloudFullRes);if (scan_pub_en && scan_body_pub_en) publish_frame_body(pubLaserCloudFullRes_body);// 添加自定義關鍵幀發布函數/******* Publish keyframe information *******/publish_key_frame_info(pubKeyFrameInfo);
-
在publish_key_frame_info函數中,我們定義了一個關鍵幀消息point_lio::key_frame_info
keyframeInfo; -
隨后,使用自定義的pointBodyToWorld函數,把原始ouster_undistort數據,轉換到了world坐標系,放到ousterCloudWorld變量中.
-
分別對ouster_undistort變量和ousterCloudWorld變量,轉換為ROS消息,放在keyframeInfo結構中.
-
使用getKeyTransformation函數獲取當前位姿,轉換為PointTypePose類型,接著放在key_frame_poses_data變量中,同樣轉換為ROS消息,放在keyframeInfo結構中,以1Hz的頻率發布.
我們的在線處理模塊,參數文件中接收對應的"/point_lio/key_frame_info"話題,即可收到關鍵幀數據,進行處理,在線進行單木屬性提取的工作.