ROS_CAMERA_INFOPUBLISHER

Question

I have a problem, that maybe I can solve here.

I created a model of cameras in gazebo and I need the cameras to generate a topical to get the information from the generated images. But I don't know how to make the camera generate the camera_info.

Answer 1

Camera info is part of the so called image_pipeline. You should use the image_publisher to fulfill the interface.

The most straight forward way would be to implement / use an image publisher in your node. Check out the API to see whats the interface. You can see a lot of examples checking available drivers. A very good example / reference impmenentation is this implementation (full file):

/** Publish camera stream topics
*
*  @pre image_ contains latest camera frame
*/
void publish()
{
    image_.header.frame_id = config_.frame_id;

    // get current CameraInfo data
    cam_info_ = cinfo_->getCameraInfo();

    //ROS_INFO_STREAM ("cam: " << cam_info_.width << " x " << cam_info_.height << ", image: " << image_.width << " x " << image_.height);
    if (cam_info_.height != image_.height || cam_info_.width != image_.width)
    {
        // image size does not match: publish a matching uncalibrated
        // CameraInfo instead
        if (calibration_matches_)
        {
            // warn user once
            calibration_matches_ = false;
            ROS_WARN_STREAM("[" << camera_name_
                                 << "] camera_info_url: " << config_.camera_info_url);
            ROS_WARN_STREAM("[" << camera_name_
                            << "] calibration (" << cam_info_.width << "x" << cam_info_.height << ") does not match video mode (" << image_.width << "x" << image_.height << ") "
                            << "(publishing uncalibrated data)");
        }
        cam_info_ = sensor_msgs::CameraInfo();
        cam_info_.height = image_.height;
        cam_info_.width = image_.width;
    }
    else if (!calibration_matches_)
    {
        // calibration OK now
        calibration_matches_ = true;
        ROS_INFO_STREAM("[" << camera_name_
                        << "] calibration matches video mode now");
    }

    cam_info_.header.frame_id = config_.frame_id;
    cam_info_.header.stamp = image_.header.stamp;

    // @todo log a warning if (filtered) time since last published
    // image is not reasonably close to configured frame_rate

    // Publish via image_transport
    image_pub_.publish(image_, cam_info_);
}