Camera calibration

Today I ran the cameracalibrator configuration file. I had to make some modifications to it due to the node I am using to communicate with the camera.


First, I verified that the camera's topics were being published.

$rostopic list


/usb_cam/camera_info
/usb_cam/image_raw


I then modified the node in the cameracalibrator.py file:

In line 128 instead of camera node we place usb_cam node:

        self.set_camera_info_service = rospy.ServiceProxy("%s/set_camera_info" % rospy.remap_name("camera"), sensor_msgs.srv.SetCameraInfo)

        self.set_camera_info_service = rospy.ServiceProxy("%s/set_camera_info" % rospy.remap_name("usb_cam"), sensor_msgs.srv.SetCameraInfo)





In line 100 as well:

            for svcname in ["camera", "left_camera", "right_camera"]:
            
            for svcname in ["usb_cam", "left_camera", "right_camera"]:


Now, in order to run the cameracalibrator node we must specify the topics we are using:


$rosrun camera_calibration cameracalibrator.py --size 6x4 --square 0.0508 image:=/usb_cam/image_raw camera:=/usb_cam

Here is a screenshot of the program's functionality:

 

Error message with Genius webcam

I was provided a new webcam to work with. It is a Genius Slim 1322AF. When trying to run usb_cam node (on dev/video1) I get the following error message:

VIDIOC_S_FMT error 22, Invalid argument


I have tested it on Ubuntu's Cheese Webcam Booth application and it works fine so I don't think the problem lays on the driver.

I am very tired... and haven't found any satisfying answer on linux forums so I'm just going to ask someone on ROS' mailing list.

Video

SLAM Mapping video

Running usb_cam node

I have created a launch file with the help from this guide: http://www.princeton.edu/~ctralie/Projects/DukeDusty2/Tutorial/

Note: /dev/video0 is the device of the integrated webcam of my laptop and /dev/video1 is the device of the Logitech Quickcam I am currently using.

When running this launch file with the /dev/video0 device I can successfully visualize video on rviz. However, a status error is displayed:

CameraInfo/P resuted in an invalid  position calculation (nans or infs)

According to ROS users, I should calibrate my camera in order to avoid this error. I had no idea on how to do so until I found this tutorial:

http://www.ros.org/wiki/camera_calibration/Tutorials/MonocularCalibration. I hope this does the trick.

Reconfiguring sicklms node

Well, after reinstalling everything in my computer and losing all my backup data (I dropped my external hard drive ¬¬), I have ROS running again.

I had some issues while configuring the sicklms node. I downloaded the original code from a ROS repository and the following error was being displayed:

A scan was probably missed. The last scan was 0.10704 seconds ago. sicklms.

I sent my inquiry to the mailing list and this was the answer.

"See https://code.ros.org/trac/ros-pkg/ticket/4673 for a ticket about that warning. How is your SICK connected to the computer? RS232 or RS422? With or without a USB->Serial adapter? At what rate should you be getting scans from the LIDAR as currently configured? 10Hz?

Is the SICK driver set to less than one degree of angular resolution? I only see this warning with my LMS291's when they are set to 0.5 degree angle increments. With 1 degree increments the warning is not output."

 

So I downloaded the code that the SSC Rovers team uses for the sicklms and it, i fact, had some differences with the degree angle increments. 

 

  }
  if (inverted) {
    scan_msg.angle_min = M_PI/2;
    scan_msg.angle_max = -M_PI/2;
  } else {
    scan_msg.angle_min = -M_PI/2;
    scan_msg.angle_max = M_PI/2;
  }
  scan_msg.angle_increment = (scan_msg.angle_max - scan_msg.angle_min) / (double)(num_values-1);
  scan_msg.scan_time = scan_time;
  scan_msg.time_increment = scan_time / (double)(num_values-1);
  scan_msg.range_min = 0;
  if (scale == 0.01) {
    scan_msg.range_max = 81;
  }
  else if (scale == 0.001) {
    scan_msg.range_max = 8.1;
  }