TimeSynchronizer (boost invalid initialization of reference)

edit

I have again a problem building the boost TimeSynchronizer Callback. I hope you can help me :)

void callback (const ImageConstPtr& right, ImageConstPtr& left) {

}


int main(int argc, char** argv) {
    ros::init(argc, argv, "stereo_vision");

    ros::NodeHandle nh;

    message_filters::Subscriber<Image> right_image(nh, "/stereo_camera/right/image_rect", 1);
    message_filters::Subscriber<Image> left_image(nh, "/stereo_camera/left/image_rect", 1);

    TimeSynchronizer<Image, Image> sync(right_image, left_image, 10);
    sync.registerCallback(boost::bind(&callback, _1, _2));


    ros::spin ();


    return 0;
}

The error msg:

error: invalid initialization of reference of type ‘boost::shared_ptr<const sensor_msgs::Image_<std::allocator<void> > >&’ from expression of type ‘const boost::shared_ptr<const sensor_msgs::Image_<std::allocator<void> > >’