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messagefillter cannot callback. (multi subscribe /scan and /camera/depth/image_rect)

asked 2015-12-28 23:26:18 -0600

haryngod gravatar image

updated 2015-12-29 03:30:47 -0600

Hi guys.

I'm try to subscribe 2 topic from /scan (laser) and /camera/depth/image_rect (depth camera) for safe wandering program. So I searched and find timesyschronizer from here for subscribing both topic sametime. however, I try to implement using that sync, it seem to be cannot callback.

before runnig this node, I run first openni2 launch and rp_lidar launch to publish data. additionally, when I subscribe each topic using simple subscriber successfully. now I'm wandering, did I use it correct way or not.

this is piece of my source code.

void callback(const sensor_msgs::LaserScan::ConstPtr& laser_msg, const sensor_msgs::Image::ConstPtr& depth_msg){
    printf("%20s:%5d : void callback(const sensor_msgs::LaserScan::ConstPtr& laser_msg, const sensor_msgs::Image::ConstPtr& depth_msg){\n",__func__,__LINE__);
    uint8_t a[10* depth_msg->width];
    sensor_msgs::Image test_image;
    sensor_msgs::Image test_dis_image;

    int test_j = 0;

    test_image.header = depth_msg->header;
    test_image.height = 10;
    test_image.width = depth_msg->width;
    test_image.encoding = depth_msg->encoding;
    test_image.is_bigendian = depth_msg->is_bigendian;
    test_image.step = depth_msg->width; * 10);
    printf("%20s:%5d : * 10);\n",__func__,__LINE__);

    for ( int j =0; j < depth_msg->step; j++){
          cout << ReadDepthData(0,(int)(j/4),depth_msg) << ", " ;

    printf("%20s:%5d : image_publisher.publish(test_image);\n",__func__,__LINE__);

int main(int argc, char **argv){
    ros::init(argc, argv, "lidar_depth_wander");    
    ros::NodeHandle n;                      

    message_filters::Subscriber<LaserScan> laser_data_sub(n, "/scan", 10);
    message_filters::Subscriber<Image> image_sub(n, "/camera/depth/image_rect", 10);
    image_publisher  = n.advertise<sensor_msgs::Image>("/test_image_raw", 10);
    printf("%20s:%5d : image_publisher  = n.advertise<sensor_msgs::Image>\n",__func__,__LINE__);
    velocity_publisher = n.advertise<geometry_msgs::Twist>("/mobile_base/commands/velocity", 10); // for kobuki
    printf("%20s:%5d : velocity_publisher = n.advertise<geometry_msgs::Twist>; \n",__func__,__LINE__);

    TimeSynchronizer<LaserScan, Image> sync(laser_data_sub, image_sub, 10);
    printf("%20s:%5d : TimeSynchronizer<LaserScan, Image>\n",__func__,__LINE__);
    sync.registerCallback(boost::bind(&callback, _1, _2));
    printf("%20s:%5d : sync.registerCallback\n",__func__,__LINE__);     

    ros::Rate loop_rate(10);
    printf("%20s:%5d : ros::spin();\n",__func__,__LINE__);

    printf("%20s:%5d : ending program;\n",__func__,__LINE__);

    return 0;

then this is CMakeLists.txt

cmake_minimum_required(VERSION 2.8.3)
find_package(catkin REQUIRED COMPONENTS geometry_msgs message_generation roscpp rospy sensor_msgs std_msgs    message_filters)
  CATKIN_DEPENDS geometry_msgs message_runtime roscpp rospy sensor_msgs std_msgs message_filters
add_executable(lidar_depth_wander src/lidar_depth_wander.cpp)
target_link_libraries(lidar_depth_wander ${catkin_LIBRARIES})
add_dependencies(lidar_depth_wander ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

last my packge.xml

 <description>The lidar_test_project package</description>
 <maintainer email="kang@todo.todo">kang</maintainer>


</export> </package>

and program result was:

 main:  187 : image_publisher  = n.advertise<sensor_msgs::Image>
 main:  189 : velocity_publisher = n.advertise<geometry_msgs::Twist>; 
 main:  193 : TimeSynchronizer<LaserScan, Image>
 main:  195 : sync.registerCallback
 main:  201 : ros::spin();                                       <-- Ctrl+C
 main:  206 : ending program;

thanks guys.

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1 Answer

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answered 2015-12-29 03:35:47 -0600

gvdhoorn gravatar image

It's rather rare for two publishers to be exactly synchronised in time, so for normal cases I'd expect the ApproximateTime Policy to be a better choice.

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Oh! thanks to you!!! it is working well to me.:)

haryngod gravatar image haryngod  ( 2015-12-29 18:15:59 -0600 )edit

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Asked: 2015-12-28 23:26:18 -0600

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Last updated: Dec 29 '15