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Help with streaming AR.Drone camera images to openCV

asked 2013-09-14 02:42:34 -0500

MichaelJ gravatar image

updated 2014-01-28 17:17:57 -0500

ngrennan gravatar image

Hello all.

I am using the AR.Drone 2.0 and setup the ardrone_autonomy driver link:text and I also installed ROS from the official website (fuerte). I am using Ubuntu 12.0.4 also.

What I would like to do is be able to write a program that takes the camera stream from the AR.Drone 2.0 and sends them to openCV. openCV is installed with my ROS distribution inside the vision_opencv folder (it has cv_bridge and openCV2 which is what I would like to use).

I have played around with openCV2 from the openCV website for single images so openCV seems to work well. I am slightly confused on how to solve the above problem because I am new to ROS and openCV. I have followed the tutorials but they do not teach me how to deal with this problem as far as I understand.

I think there are two problems to what I want to do. 1) send camera images directly from the AR.Drone to ROS. 2) send images from ROS format to openCV and do this the other way around. I read that cv_bridge does this but slightly overwhelmed by it.

Ideally, I want a GUI with the images going into openCV but how will I know if the images are successfully going into openCV? openCV is just a package and doesnt seem to have an interface like MATLAB so I want to also understand what kind of output I should expect to know if the program is working correctly. Any help will be great!

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How are the images currently streamed? Can it be used as a sort of IP cam? OpenCV has support for IP cams.

davinci gravatar image davinci  ( 2013-09-15 04:40:36 -0500 )edit

Currently, the images stream using Qt from the code provided by the ardrone_tutorials. The ardrone sends the images through the generates an ad-Hoc wifi. What does IP stand for?

MichaelJ gravatar image MichaelJ  ( 2013-09-15 04:56:01 -0500 )edit

Do you want to get the stream from the AR.Drone in order to process it with OpenCV?

Pedro_85 gravatar image Pedro_85  ( 2013-10-30 06:36:23 -0500 )edit

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answered 2013-10-30 11:29:16 -0500

Pedro_85 gravatar image

The AR.Drone Autonomy package publishes the video captured by the cameras in the topic /ardrone/image_raw topic. I have prepared a simple code that works with opencv so that you get the idea:

#include <ros/ros.h>
#include <image_transport/image_transport.h>
#include <sensor_msgs/image_encodings.h>
#include <cv_bridge/cv_bridge.h>
#include <cv_bridge/CvBridge.h>
#include <opencv2/highgui/highgui.hpp>

using namespace std;
using namespace cv;

static const char WINDOW[]="RGB Image";
static const char WINDOW2[]="Gray Image";

void process(const sensor_msgs::ImageConstPtr& cam_image){
   sensor_msgs::CvBridge bridge; 
   Mat img_rgb = bridge.imgMsgToCv(cam_image,"bgr8"); 
   Mat img_gray;

   cvtColor(img_rgb,img_gray,CV_RGB2GRAY);

   imshow(WINDOW,img_rgb);
   imshow(WINDOW2,img_gray);
   cvWaitKey(1);
}

int main(int argc, char **argv){
  ros::init(argc,argv,"Display_Images");
  ros::NodeHandle n;
  image_transport::ImageTransport it(n);
  image_transport::Subscriber image_sub = it.subscribe("/ardrone/image_raw",1,process);

  cv::namedWindow(WINDOW);
  cv::namedWindow(WINDOW2);

  cv::destroyWindow(WINDOW);
  cv::destroyWindow(WINDOW2);

  ros::spin();
  return 0;
}

If you are interesed in switching between the front and bottom cameras you can use the command:

rosservice call /ardrone/togglecam

You can also subscribe to /ardrone/bottom/image_raw if you want to work only with the bottom camera.

I hope this helps.

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That helps so much, thank you! Out of curiosity, are you working with the ardrone_autonomy package? Have you been getting a nice stream output or does it produce blurry/double images?

MichaelJ gravatar image MichaelJ  ( 2013-10-30 11:38:57 -0500 )edit

Yes I'm working with the ardrone_autonomy package. The images are of good quality. Good luck!

Pedro_85 gravatar image Pedro_85  ( 2013-10-30 11:44:27 -0500 )edit

Thanks. So when you ran rosrun image_view image_view image :=/ardrone/front/image_raw, was the image quality good? Did you change any code in the ardrone autonomy or calibrate the camera?

MichaelJ gravatar image MichaelJ  ( 2013-10-30 13:26:23 -0500 )edit

Hello, I have the cv_bridge.h but not the CvBridge.h , my prog can't be run because of this include. How can I fix this? Thank you!

huevos gravatar image huevos  ( 2014-12-17 09:23:32 -0500 )edit

I have some probelm with huevos, if you dont mind please upload your CvBridge.h thanks

ffazlurr gravatar image ffazlurr  ( 2015-07-01 01:28:08 -0500 )edit

Hello! I`m new in ROS. What I have to do to run the code above? Do I have to compile? Thanks

renanchagas gravatar image renanchagas  ( 2015-08-24 20:24:00 -0500 )edit

I tried running this program, but I got this error when I built it even after I installeed the vision_opencv package

fatal error: cv_bridge/CvBridge.h: No such file or directory

compilation terminated. findtag/CMakeFiles/detect.dir/build.make:62: recipe for target 'findtag/CMakeFiles/detect.di

enthurzan gravatar image enthurzan  ( 2017-07-06 10:21:27 -0500 )edit
0

answered 2013-09-18 23:48:45 -0500

davinci gravatar image

Here is the image stream described: http://www.rosbridge.org/doku.php?id=tutorials:ardrone

You can import the mjpeg stream in OpenCV or in ROS through cv bridge. Here is an example for OpenCV: http://answers.opencv.org/question/133/how-do-i-access-an-ip-camera/

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Thanks for the reply. Is there any examples that use the AR.Drone 2.0 camera? The first link is for ardrone 1.0 and is just a browser to control the drone. I want to perform image processing on the images. The second link is too generic for me. Is the ardrone camera called an ip camera?

JP gravatar image JP  ( 2013-09-19 01:51:29 -0500 )edit

I think you can treat it as an ip camera (network camera) with an mpjeg image stream that you can process in OpenCV. How do you mean to generic? It is a start to read out the images and after that you can start processing.

davinci gravatar image davinci  ( 2013-09-19 02:30:48 -0500 )edit

I say it is too generic because there are no ardrone_autonomy imports that work specifically for the ardrone camera. I would have to modify the code to get it to work and that will cause more problems I think.

JP gravatar image JP  ( 2013-09-19 02:37:21 -0500 )edit

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Asked: 2013-09-14 02:42:34 -0500

Seen: 6,066 times

Last updated: Oct 30 '13