callback for two topics at the same time

edit

Hi everyone,

I would like to save an image from a depthcamera and a webcam at the same time as a mouse click. So I subscribed to the depth image and in this callback I used

 webcam_image = ros::topic::waitForMessage<Image>("/logitech_usb_webcam/image_raw");

but it seems that the wait for message skips the first message and uses the second one instead...

So I went on and tried another solution. Therefore, I used the registerCallback function from the message_filter package but it doesn't behave like I want it because the callback gets never triggered (both topics are published).

My code looks like this

#include <ros/ros.h>
#include <std_msgs/String.h>
#include <message_filters/subscriber.h>
#include <message_filters/time_synchronizer.h>
#include <sensor_msgs/Image.h>


using namespace sensor_msgs;
using namespace message_filters;


void sync_callback(const ImageConstPtr& depth_image, const ImageConstPtr&  webcam_image){

        ROS_INFO("syncro callback");
}



int main(int argc, char **argv){

        ros::init(argc, argv, "listener");
        ros::NodeHandle nh;

        message_filters::Subscriber<Image> depth_sub(nh, "/camera/depth/image", 1);
        message_filters::Subscriber<Image> webcam_sub(nh, "/logitech_usb_webcam/image_raw", 1);
        TimeSynchronizer<Image, Image> sync(depth_sub, webcam_sub, 50);
        sync.registerCallback(boost::bind(&sync_callback, _1, _2));



        ros::spin();
        return 0;
}

Would be great to get your help to get this working.