How to pass publisher to callback

edit

How to pass publisher to callback, as far as I can see this should work but keep getting errors: The two param case works without the publisher being passed.

 ImageGrabber igb(&SLAM);
ros::NodeHandle nh; 
ros::Publisher pub = nh.advertise<sensor_msgs::Image>("/camera/depth-converted/image_raw", 1);

message_filters::Subscriber<sensor_msgs::Image> rgb_sub(nh, "/camera/rgb/image_raw", 100);
message_filters::Subscriber<sensor_msgs::Image> depth_sub(nh, "camera/depth_registered/image_raw", 100);
typedef message_filters::sync_policies::ApproximateTime<sensor_msgs::Image, sensor_msgs::Image> sync_pol;
message_filters::Synchronizer<sync_pol> sync(sync_pol(10), rgb_sub, depth_sub, &pub);
sync.registerCallback(boost::bind(&ImageGrabber::GrabRGBD, &igb, _1, _3));

call back def:

void ImageGrabber::GrabRGBD(const sensor_msgs::ImageConstPtr& msgRGB,const sensor_msgs::ImageConstPtr& msgD, const ros::Publisher *pub)

error:

error: no matching function for call to ‘message_filters::Synchronizer<message_filters::sync_policies::ApproximateTime<sensor_msgs::Image_<std::allocator<void> >, sensor_msgs::Image_<std::allocator<void> > > >::Synchronizer(sync_pol, message_filters::Subscriber<sensor_msgs::Image_<std::allocator<void> > >&, message_filters::Subscriber<sensor_msgs::Image_<std::allocator<void> > >&, const ros::Publisher*)’
     message_filters::Synchronizer<sync_pol> sync(sync_pol(10), rgb_sub, depth_sub, &pub);